NN Vol13 n1 DEF - Istituto Nazionale di Fisica Nuclearestatistics.roma2.infn.it/~notiziario/2008/pdf/vol13-n1_08.pdf · grammes at Risø starting in FP3 in 1991. By 1993 five other

Vol. 13 n. 1 January 2008

NOTIZIARIONeutroni e Luce di Sincrotrone

Rivista delConsiglio Nazionaledelle Ricerche

www.cnr.it/neutronielucedisincrotrone

EDITORIAL NEWSNeutrons and muons: how to succeed in FP7? .................. 2R. McGreevy

Fermi@Elettra: the new Free Electron Laserwill be operating in 2009. It will allow the studyof the dynamic properties of matter ................................................ 3L.B. Palatini

SCIENTIFIC REVIEWSARCS: a wide Angular-RangeChopper Spectrometer at the SNS ...................................................... 4D.L. Abernathy

Brillouin scattering of neutrons for the studyof the microscopic dynamics of fluids ........................................... 8U. Bafile, F. Barocchi, E. Guarini

Bose-Einstein Condensationand Supersolid Helium ................................................................................. 14J. Mayers

RESEARCH INFRASTRUCTURESISIS Second Target Station Project ................................................... 21M. Bull

Experiments underway at UK’s new synchrotron ..... 22S. Damerell, S. Fletcher

BaD ElPh: a new beamline for band dispersionand electron-phonon coupling studiesat ELETTRA ................................................................................................................. 25P. Vilmercati et al.

MUON & NEUTRON & SYNCHROTRON NEWSNews from ILL ......................................................................................................... 29

News from SNS ....................................................................................................... 33

SCHOOL AND MEETING REPORTS ................................................................................. 35

CALL FOR PROPOSALS .............................................................................................................. 36

CALENDAR .............................................................................................................................................. 38

FACILITIES ............................................................................................................................................... 41

S U M M A R YCover photo:Fermi@Elettra layout.

published by CNR in collaborationwith the Faculty of Sciences and thePhysics Department of the Universityof Rome “Tor Vergata”.

Vol. 13 n. 1 Gennaio 2008Autorizzazione del Tribunale diRoma n. 124/96 del 22-03-96

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NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 13 n. 1 January 2008

E uropean neutron and muon facilities havebeen successfully involved in EU FrameworkProgrammes since their earliest days. Con-struction of the ISIS muon facility started

with the help of EU funding from FP1 in 1985. KurtClausen ran one of the very first EU Access pro-grammes at Risø starting in FP3 in 1991.By 1993 five other neutron and muon facilities werealso offering EU funded access. Mike Johnson coordi-nated ENNI, the first neutron related research andtechnical development project in FP3, then XENNI inFP4 and TECHNI in FP5; there were six other RTDprojects in FP4 and five in FP5.The Neutron Round Table was one of the first to be es-tablished, coordinated by Charles de Novion in FP3and then Kurt Clausen in FP4 and FP5. In FP6 all ofthe neutron and muon facility related activities weregrouped into a single project - NMI3 - the IntegratedInfrastructure Initiative for Neutron Scattering andMuon Spectroscopy.NMI3 is the second largest I3 project, the synchrotronproject IA-SFS being the largest, and includes EU ac-cess to all European neutron/muon facilities apartfrom ILL, eight Joint Research Activities, and network-ing activities which replace the previous Round Table.Building on the very solid foundations of all the pro-jects in previous Framework Programmes, NMI3 hasestablished a very high profile and has been consid-ered a model for how European research infrastruc-tures can work effectively together. So what does thefuture hold?In FP7 the Research Infrastructures budget is not aslarge as had been hoped. With big new activities, suchas Preparatory Phase projects for the 35 potential facil-ities on the ESFRI Road Map and 29 potential targetedI3 projects related to the FP7 Thematic Priorities, therewill be significant pressure on the budgets for the “tra-ditional” I3.This is a great pity, since these I3 are seen to be one ofthe more generally successful areas of EU funding

when it comes to useful pan-European collaboration.EU funding to neutrons and muons has been of order5M€ per year since 2000.The total funding of European neutron and muon fa-cilities exceeds 200M€ per year, so the EU contribu-tion is only a small percentage. Of course all addition-al money is useful, particularly that coming from Ac-cess since it is a direct payment for a service delivered,with no strings attached.But there are significant opportunities for savingswithin normal development budgets if we collaboratemore, rather than compete. Despite the high level ofbureaucracy, and the emphasis on project manage-ment over scientific and technical excellence, organisa-tions actually appear to like the fact that the EU offersa defined collaboration framework, rather than havingto set it up for themselves. But it is time that we over-came this reluctance – otherwise FP7 may start to seeneutron and muon facilities moving apart for the firsttime in over 20 years.

R. McGreevy

FP6 NMI3 Coordinator

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Vol. 13 n. 1 January 2008 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

T he “seeded” free-electron laser project FER-MI@Elettra when completed will be a new 4th-Generation Synchortron Light Source. It willprovide time-synchronized ultrashort fem-

tosecond pulses and so will be used to explore topicssuch as ultrafast spectroscopies and microscopies. Assuch it will be one of the first Free-Electron Laser of itskind operating in the world for a broad user commu-nity covering the wavelength range from 100 nanome-ters to below 10 nanometres (from Vacuum-Ultravio-let to Soft X-Rays) with high peak-brightness, ultra-short length, and transverse and longitudinally coher-ent light pulses. The FERMI@Elettra project is locatedat the Elettra Laboratory, an international “open ac-cess” Laboratory whose mission is that of hosting re-searchers from any Country on the basis of quality-se-lected proposals. The flashes produced by FERMI willcover a time-span reaching below 100 femtoseconds.This will allow researchers to expand the boundariesfrom static observation of materials to the dynamicanalysis of their behaviour, and to follow the workingmechanism of different materials (ranging from phar-maceuticals to catalysts) by observing the evolution ofproperties on a time scale of atomic and electronicphenomena. The very high-peak light intensity will al-so allow researchers to excite atoms and create andstudy warm dense matter, a state of matter similar to aplasma but with very high density, that is the state ofmatter at the core of large planets. Thanks to the syn-chronization capability there will also be the possibili-ty to use “pump and probe” techniques, and followelectronic and chemical processes. The community ofsynchrotron light and lasers users has been continu-ously involved in defining the possible applicationsand therefore the fundamental source parameters andconfiguration of FERMI@Elettra. The main experi-mental programs have been selected to converge intothe following three core areas: Low-Density Matter(dedicated to cluster electronic structure, atomic andmolecular chemistry, and atomic and molecular

physics), Elastic and Inelastic Scattering (dedicated toanalyse excitation and structure of glasses and liquidsand structure of materials in extreme conditions), andDiffraction and Projection Imaging (dedicated to sin-gle-shot microscopy, single-shot diffraction and coher-ent imaging). Similarly the conceptual design studyfor FERMI@Elettra has been developed in collabora-tion with most other laboratories involved in similarprojects in the world, and in particular with the EU-ROFEL network in Europe and with the LawrenceBerkeley National Laboratory, the Massachussets In-stitute of Technology (MIT), and the Stanford LinearAccelerator Center (SLAC) in the USA. Jointly the var-ious European 4th generation light sources are beingdeveloped in a coordinated effort, and the variousprojects formed a joint Consortium (IRUVX) at theend of 2006. This consortium aims at making the bestuse of services by exploiting the possible complemen-tarities of the projects and the affiliated laboratories;furthermore, this approach is strongly endorsed andsupported by the European Union. The different facili-ties are able to cover different parameter ranges, thushelping to extend the use of FEL-generated light overa much wider range of scientific fields. The 124 mil-lion Euro project FERMI@Elettra is funded by the Ital-ian Government, the Friuli Venezia Giulia region andthe European Union, and the project-financing is com-pleted through an Italian government guaranteed loanfrom the European Investment Bank.

L.B. Palatini

Sincrotrone Trieste

Fermi@Elettra: the new Free ElectronLaser will be operating in 2009.It will allow the study of the dynamic properties of matter

Fermi@Elettra layout.

4

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AbstractARCS, a wide angular-range thermal to epithermal neutronspectrometer, is one of an extensive suite of inelastic instru-ments in operation or under construction at the SpallationNeutron Source (SNS) at Oak Ridge National Laboratory. Byproviding a high flux of neutrons with moderate resolutionand a large detector coverage, ARCS will enable studies of ex-citations from a few to several hundreds of meV in fields suchas lattice dynamics and quantum magnetism. The construc-tion phase of the ARCS project was completed in September2007 with several demonstration measurements. CurrentlyARCS is being commissioned, and will enter the SNS generaluser program in the fall of 2008.

IntroductionARCS is one of a suite of seven inelastic instruments atthe Spallation Neutron Source (SNS) at Oak Ridge Na-tional Laboratory (ORNL) which covers a wide range ofenergy transfer (Ω) and momentum transfer (Q) space.Furthermore, each spectrometer provides unique resolu-tion conditions for both Q and Ω, and the set comple-ments the existing triple-axis capabilities at the HighFlux Isotope Reactor (HFIR) at ORNL. [1,2]The inelastic instruments at the SNS are in variousstages of installation, commissioning and operations.The Backscattering Spectrometer (BASIS) is installed andis in the SNS general user program, with a demonstrated

ARCS: a wide Angular-Range Chopper Spectrometerat the SNSD.L. AbernathyNeutron Scattering Science Division,Oak Ridge National Laboratory, USA

Figure 1. Overview of ARCS with components labeled.

5

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energy resolution of 3 µeV. The ARCS wide Angular-Range Chopper Spectrometer, which initiated first oper-ations with neutrons in September 2007, and the ColdNeutron Chopper Spectrometer (CNCS) scheduled forcommissioning in 2008, provide moderate resolutionand the ability to trade resolution for flux. In additionboth instruments have detector coverage out to 140o toprovide a large Q range. SEQUOIA, a direct-geometryinstrument that has finer resolution in the thermal andepithermal energy range, will begin commissioning in2008. Following shortly will be the Neutron Spin-Echospectrometer (NSE), providing the finest energy resolu-tion of the inelastic suite. The HYSPEC spectrometer,available by 2011, will have polarized capabilities andoptimized flux in the thermal energy range. Finally, theVISION chemical spectrometer will use crystal analyzersto study energy transfers into the epithermal range willbe available by 2012.

ARCS instrument descriptionARCS, located at beamline 18 of the SNS, is optimized toprovide a high neutron flux at the sample and a large

solid angle of detector coverage. The spectrometer is ca-pable of selecting incident energies (Ei) over the full en-ergy spectrum of neutrons provided by the ambient wa-ter moderator, making it useful for studies of excitationsfrom a few to several hundred meV. Primary science ar-eas for the instrument include the study of lattice dy-namics, such as measuring the phonon density of statesof diverse materials, and applications to magnetic dy-namics in systems from high temperatures superconduc-tors to low dimensional quantum magnets. Guidance forthe scientific applications, development and initial use of

the instrument has come from an active Instrument De-velopment Team (IDT). Professor Brent Fultz from theCalifornia Institute of Technology is the Principal Inves-tigator for the United States Department of Energy (U.S.DOE) grant to build ARCS.An overview of the instrument is shown in Figure 1,with key components indicated on a cutaway view ofthe ARCS engineering model [3]. There are 8 meters ofhigh index (m= 3.6) elliptically-shaped supermirrorguide in the incident flight path, which boosts the per-formance up to an order of magnitude in the lower Ei

range. A cylindrical array of 115 modules of 8 one meterlong 3He linear position sensitive detectors (LPSDs) isinstalled within a combined sample and detector vacu-um chamber. This scattering chamber provides a win-dow-free final flight path and incorporates a large gatevalve to allow rapid sample change out.Figure 2 shows the view from the low angle area withinthe scattering chamber toward the neutron guide, sam-ple position and high angle detectors. ARCS has twoFermi choppers mounted on a translation stage in the in-cident shielding. These devices select the desired Ei, ro-

tating at speeds up to 600 Hz and phase locking to thesource pulse to better than 1 microsecond, and may beswapped in minutes to allow the instrument resolutionto be matched to the experimental requirements withoutthe need to remove heavy shielding blocks.Figure 3 shows the two Fermi choppers mounted in theincident beamline two meters before the sample posi-tion, as well as a variable aperture, beam monitor and re-movable and fixed neutron guides leading into the sam-ple chamber. ARCS has undertaken a number of techni-cal challenges during the project. To increase safety by

Figure 2. View from the low angles toward the sample and high angledetectors. The neutron guide enters the sample chamber at the left, tran-sporting neutrons to the sample position. A large semi-circular gate valve(open) can be raised to isolate the sample volume for rapid changes ofsample environment.

Figure 3. View from above of the neutron optics for ARCS just beforethe sample chamber. Neutrons come from the guide system at the top,pass through one of two Fermi choppers mounted on a translation ta-ble, a variable aperture, beam monitor, and removable and fixed neu-tron guides.

avoiding large, thin windows and to optimize space uti-lization, the 3He linear sensitive detectors together withtheir digitizing electronics operate inside the scatteringchamber vacuum.Novel B4C internal shielding uses no hydrogen in thebinder material to reduce instrument background andimprove vacuum performance. A new T0 neutron chop-per, which blocks the fast radiation from the sourcewhen the proton beam hits the target, is being developedin collaboration with the SNS instruments SEQUOIAand HYSPEC. It will not only block the prompt radiationfrom the source but also eliminate unwanted neutronsfrom the incident beam line by utilizing a vertical axisdesign inspired by the first choppers in the IntensePulsed Neutron Source spectrometers. This chopper will be available by mid-2008 and testedbefore general user operations in the Fall 2008. In addi-tion to the instrument hardware, the ARCS project in-cluded a significant effort for software development [4].A collaboration between software engineers and neutronscattering scientist led by the ARCS Principal Investiga-tor has produced robust data reduction and analysistools gathered into a version 1.0 release of the packageData Reduction for Chopper Spectometers (DRCS, ormore affectionately, “DrChops”). As of August 2008,DRCS supports reduction of data from the direct-geome-try, time-of-flight chopper spectrometers LRMECS,Pharos, and simulations of ARCS data sets.Modules are available for multiphonon corrections andfor direct manipulations of data objects with standardsoftware tools. This software is installed on a powerfulcomputer cluster installed next to the ARCS Data Acqui-sition System (DAS), and the procedures to provide realtime as well as post-experiment analysis will be commis-sioned as the instrument itself is.All software developments have been carefully coordi-nated with SNS initiatives to provide data storage andvisualization tools.

ARCS initial measurements and commissioning plansARCS took initial neutrons for first testing of the over-all instrument performance in September 2007. Due tothe source run schedule, only a few basic tests wereperformed in order to demonstrate that the neutron op-tics system was operating as expected, and that theoverall data collection and storage performed correctly.In addition to these tests, images of the beam at thesample location and at the beam exit from the scatter-ing chamber were taken using neutron-sensitive imageplates to confirm the correct positioning and homo-geneity of the beam.Figure 4 shows the counts per 10 µs time bin in the up-stream ARCS beam monitor during a run of approxi-mately 800 seconds at an SNS beam power of 125 kW

operating at 30 Hz. The monitor was calibrated by theSNS detector group and found to have an efficiency of1.0 ± 0.1 x 10-5 at a wavelength of 1.8 Å. The ARCS moni-tor does not provide reliable data at times less than ap-proximately 1 msec after the proton pulse on target dueto the high prompt radiation that is not currentlyblocked by a T0 chopper. The peak at moderate neutronenergies is clearly seen in the data, corresponding to thethermalized beam from the 25mm depth poisoned, de-coupled water moderator. The sharp spike at 33 msec isthe next prompt radiation pulse due to the 30 Hz protonon target operations. Also plotted in Figure 4 are the ab-solute intensities expected from the calibrated beammonitor based on the performance of the facility as cal-culated by the SNS neutronics group [5], taking into ac-count the beamline geometry and source power. Data

with and without the calculated guide gain from theARCS neutron guide system up to the monitor positionare shown. The source calculation and neutron guideperformance match the data collected on ARCS withinreasonable accuracy, demonstrating that the instrumentis performing as expected. In addition to the beammonitor data, powder diffraction data was collected ina subset of the ARCS detector array mounted in the in-strument detector chamber. Eight of the detector mod-ules were placed near 90° scattering angle and variousdata sets were collected. Figure 5 shows the results ofthe scattering from a silicon powder sample contained inan aluminum sample can. The data has been correctedfor the individual pixel scattering angles and final flight-paths and binned according to the measured crystal lat-tice plane (d) spacing. As can be seen from the plot, thediffraction lines may be seen above a large backgrounddue to air scattering. The positions of the expected linesare shown for some of the larger d-spacings in silicon

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Figure 4. ARCS beam monitor data compared to calculations from theSNS neutronics group with and without the calculated ARCS guide gain.

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and aluminum, and these correspond well with the ac-quired data using the geometry of the instrument as de-signed. Since these initial results, the integration of ad-ditional spectrometer components was resumed withthe goal of making detailed calibration and verificationmeasurements during the November 2007 to February2008 SNS run cycle.The installation and operation of up to 115 LPSD mod-ules consisting of 8 LPSDs each inside a vacuum cham-ber is a large challenge that is moving ahead smoothly.Additional shielding for background suppression, bothinside and outside of the scattering chamber, is also be-ing added. Once basic operation of the instrument is sat-isfactory, the IDT will be solicited for early experimentsto test the new spectrometer’s capabilities in a widerange of scientific applications.

ConclusionsARCS is the second spectrometer at the SNS to begin op-erations, joining the Backscattering Spectrometer andleading a strong contingent of new additions to follow.The commissioning phase for ARCS is well underway,and initial experiments to follow will explore a variety ofresearch opportunities in condensed matter physics.By combining the hardware developments with newsoftware, ARCS will be well positioned to take advan-tage of the rapid progress in source power and reliabilityat the SNS.

AcknowledgmentsThe ARCS project was only made possible by the sup-port of numerous colleagues at the SNS, Caltech and theIDT members. In particular, expert design work was pro-vided by K. Shaw and S. Howard, outstanding supportfor neutronic calculations by E. Iverson, and excellent in-stallation and operational support by M. Loguillo. ARCSwas supported by the U.S. DOE under grant DE-FG02-01ER45950. ORNL/SNS is managed by UT-Battelle,LLC, for the U.S. DOE under contract DE-AC05-00OR22725.

References1. G. Granroth, D. Abernathy, G. Ehlers, M. Hagen, K. Herwig,

E. Mamontov, M. Ohl, and C. Wildgruber, The Inelastic Instrument suiteat the SNS, Proceedings of the International Collaboration onAdvanced Neutron Sources XVIII (2007)

2. http://neutrons.ornl.gov/index.shtml

3. D.L. Abernathy and K.M. Shaw, Design Criteria Document for the wideAngular Range Chopper Spectrometer (ARCS), SNS Document ARCS18-00-DC0001-R01 (2004)

4. http://arcscluster.caltech.edu:5001/. Note that the ARCS softwaredevelopment has transitioned smoothly to a larger developmentproject called DANSE (Distributed Data Analysis for NeutronScattering Experiments). See:http://wiki.cacr.caltech.edu/danse/index.php/Main_Page

5. E.B. Iverson, P.D. Ferguson, F.X. Gallmeier and I.I. Popova, DetailedSNS neutronics calculations for scattering instrument design: SCTconfiguration, Technical Report SNS 110040300-DA0001-R00 (2002)

Figure 5. Diffraction data from a silicon powder in an aluminum can. The peaks due to the powder diffraction lines sit on top of a large background dueto air scattering. Some expected peak positions are shown by the symbols.

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Brillouin scattering of neutrons for the studyof the microscopic dynamics of fluidsU. Bafile1, F. Barocchi2, E. Guarini2

1 Consiglio Nazionale delle Ricerche,Istituto dei Sistemi Complessi, via Madonna del Piano 10,I-50019 Sesto Fiorentino, Italy

2 Dipartimento di Fisica, Università di Firenze,and CNR-INFM CRS-Soft, via G. Sansone 1,I-50019 Sesto Fiorentino, Italy

AbstractBrillouin scattering is the spectroscopic technique applied tothe probing of acoustic excitations in condensed matter.Significant advances in instrumentation have led to the devel-opment of various Brillouin spectroscopies in addition to thefirst exploited light scattering methods, extending the study ofsound propagation to a very wide range of excitation wave-lengths. The role of Brillouin scattering of neutrons is dis-cussed and a few examples are given of its potentiality for anin-depth investigation of microscopic dynamics and interac-tions in fluids.

Since the 60s of last century, the study of sound propaga-tion in the microscopic domain, and of the dampingprocesses that accompany it, has been a typical field ofspectroscopic application of laser sources with the mea-surements of Brillouin light scattering spectra.This experimental method, when applied to fluids, hasprovided a wealth of quantitative information on the dy-namics of a variety of gaseous and liquid systems at theatomic or molecular level. One main reason for such anexploitation of light Brillouin spectroscopy, besides therelatively low cost of the instrumental setups, is theavailability of an accurate theoretical framework able toaccount in detail for the observed dynamics.Indeed, in the wavevector range typically explored insuch experiments, the explicit formulation of the line-shape in terms of thermodynamic and transport prop-erties of the fluid under study is accurate enough tocarry out spectroscopic measurements of thermophysi-cal parameters from the spectral features.It is well known that the detected Rayleigh-Brillouin(RB) light spectrum closely reflects the dynamic struc-ture factor S(Q,ω) as obtained from linearized-hydrody-namics theory [1].The variables Q and ω are the wavevector and frequen-cy, to be identified, respectively, with the momentumand energy (in units of the Planck constant h- ) trans-ferred to the sample in the scattering process, andS(Q,ω) represents, at constant Q, the frequency spec-trum of the autocorrelation function of density fluctua-tions with wave vector magnitude Q, i.e. of the inter-mediate scattering function F(Q,t).The hydrodynamic line shape, in the simplest case of amonatomic liquid composed of atoms of mass m at a

number density n, is

(1)

Here, γ0 is the ratio of the constant-pressure (cp) to theconstant-volume (cv) specific heat, DT = λ/ncp is the ther-mal diffusivity with λ the thermal conductivity,Γs = [(γ0 - 1)DT + ν]/2 is the sound damping coefficient,ηs, ηb, and ν = [(4/3)ηs + ηb]/mn are the shear, bulk, andkinematic longitudinal viscosities, respectively,bs = [3(γ0 - 1)DT + ν]Q/(2cs) , and finally cs = 1/√nmχs andχs are the adiabatic sound speed and compressibility.The static structure factor S(Q) is the frequency integralof S(Q,ω). At constant Q, equation (1) represents a fre-quency spectrum composed by a triplet of lines, one(Rayleigh, quasielastic) centred at ω = 0 and two (Bril-louin, inelastic) symmetrically shifted at the positions ω= ± csQ determined by the acoustic excitation frequencywhich, then, follows a linear dispersion law. All lines areLorentzians with half widths at half maximum increas-ing quadratically with Q. Actually, the Brillouin lines aremodified by the presence of extra terms that introducean asymmetric distortion, but their effects is quite smalland often negligible. The Q values typically attained inBrillouin light scattering are of the order of 10-2 nm-1,where S(Q ) can be safely approximated by S(0) =nkBTχsγ0, where kB is the Boltzmann constant and T is thetemperature of the fluid. With a wavelength in the rangeof visibile radiation, the microscopic discreteness of mat-ter does not come into play and the fluid is probed as acontinuous medium, accordingly to the hydrodynamicassumption. If is a typical length scale related to thedistance within the particles, such a condition can be ex-pressed as Q « 1. The onset of non-hydrodynamicregime, where the fluid behaves as a discrete collectionof individual particles, is ruled by the increase of Q upto values of the order of unity. With light scattering, thisis possible by increasing towards values typical of di-lute gases, but non-hydrodynamic sound-like excitations

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have also been detected by neutron scattering in manydense liquids, including, for example, liquid metals, re-vealing the need for experimental techniques able todeal with Q ranges above the light scattering situationwhile keeping within the dense-fluid interparticle dis-tances. This goal has prompted several efforts aimed atdeveloping instrumentation for spectroscopic studiesoutside the hydrodynamic regime. Standard neutronscattering, however, typically applies for Q > 2 nm-1, andneeds to be extended down to at least one-order-of-mag-nitude lower Q values. This requirement of very low Qis to some extent in conflict with the need of an incidentneutron speed larger than the sound velocity in the ma-terial, a necessary condition to probe acoustic excita-tions. The better compromise is obtainable the lower isthe scattering angle, and, from an instrumental point ofview, neutron Brillouin scattering can indeed be seen asinelastic small-angle scattering. Thus, the first successfulattempt towards a specialized spectrometer was made,nearly twenty years ago, by modifying, though not per-manently, an existing one (namely, the time-of-flight,cold-neutron IN5 spectrometer of ILL) with the additionof a two-dimensional small-angle detector [2]. The stateof the art in this field is now represented by the fullydedicated thermal-neutron spectrometer BRISP, also atILL, very recently become operational [3].Although this paper is specifically concerned with neu-tron Brillouin scattering, it is appropriate to mention thatother spectroscopic techniques have also been recentlydeveloped to address the same scientific issues. For in-elastic x-ray scattering, the most stringent technical re-quirement is the resolution power, which must be largeenough to resolve energy separations of the order of1 meV with incident energies in the tens of keV range.Such high photon energies, on the other hand, removethe kinematical restrictions typical of neutron scattering.This technique is thus best suited to the study of high-frequency excitations.Though the concept of high-resolution inelastic x-rayspectrometry dates back to the years 80s [4], its system-atic application to the study of fluids dynamics beganaround the mid 90s at ESRF [5] and, later, at other syn-chrotron sources. Even more recently, Brillouin scatter-ing performed with synchrotron ultraviolet radiationwas also demonstrated to be able to cover the Q gap be-tween light scattering and the other methods [6]. All to-gether, the whole set of available experimental tech-niques can now cover continuously a very broad Qrange. This fact is especially important if one considersthat, as we will show later, the theoretical developmentsenabling a detailed description of the detected frequencydistributions are essentially the same in the wholewavevector range of interest for the study of collectiveacoustic excitations. As a consequence of this remarkable

progress of instrumental capabilities, a great amount ofexperimental work has been performed in the last abouttwenty years in the field of the microscopic collective dy-namics of various kind of fluids. Experimental resultsare usually analysed by fitting to constant-Q spectral da-ta a suitably parametrized model of the classical S(Q,ω),modified to account for detailed-balance asymmetry andinstrumental resolution broadening. By performing themodel fitting separately at each investigated Q value, anexperimental Q-dependence is obtained for each fit para-meter. Expression (1) typically describes a triplet ofsharp and well-separated lines, a well-known examplebeing the Brillouin spectrum of liquid argon in figure 3of Ref [7]. Instead, in the Q-range of neutron scattering,the acoustic excitations usually produce a much lessstructured spectral shape displaying, at most, weak sideshoulders. This fact makes the determination of the peakfrequencies a difficult task for which different criteriahave been applied. Analogously, the evaluation of the Q-range where collective excitations have a propagatingnature has also been based on various, sometimes quali-tative, criteria to decide whether the sound modes are tobe considered as under- or overdamped.In a recent paper [8] we showed how both the abovementioned problems can be solved rigorously. Reliabletools are thus nowadays available for a full characteriza-tion of the collective excitations in a large variety of flu-ids. On the contrary, much less work has been devotedso far to the more fundamental issue of the connectionbetween the emergence of such dynamical behavioursand the underlying interaction forces among particles.The way in which the details of the potential functionsaffect the Q dependence of the various relaxation mecha-nisms associated to collective motions has not been elu-cidated yet, not even qualitatively. The molecular-dy-namics (MD) simulation technique can play here an es-sential role, offering the possibility to study the micro-scopic motions for different model interaction potentials.We will discuss later an example of the joint applicationof neutron Brillouin scattering and MD simulation to thestudy of microscopic interactions. First, a short summaryof the results recently obtained for the description of col-lective sound modes is presented.At low enough Q, where acoustic excitations propagatein a fluid, the normalized dynamic structure factor canbe written in the form

(2)

Here the last two terms are the spectral signature of theacoustic modes (the subscript s stands for “sound”) andrepresent the Brillouin lines, having a Lorentzian shapecentred at ω = ±ωs with half width zs, and distorted bythe presence of the asymmetry parameter bs. The otherterms in the sum are also Lorentzian lines, symmetricand centred at ω = 0 , with half width -zj . The meaningof the quantities zj will be explained here below.Equation (2) is derived naturally from the memory func-tion approach customarily adopted for the theoreticaldescription of the collective dynamics of a fluid, andtreated in detail in standard textbooks on the subject [1].The basic idea behind this formulation is that the timeevolution of F(Q,t) can be described by a Langevin-likeequation modified by the introduction of a memoryfunction M(Q,t) that expresses the effect at a given time tof the past dynamics, thus allowing for non-locality intime. The actual dynamical behaviour then depends onthe choice of a suitable memory function, which howev-er cannot be determined from theoretical arguments.One appealing feature of the memory function approachis that very simple expressions of M(Q,t) produce quiterealistic models for the spectral distribution. Indeed, innearly all experimental works published on the subject,spectral data were accurately accounted for by memoryfunction models as simple as a sum of exponential de-cays. It was then shown in [8] that, in all such cases, (I)one obtains equation (2) with a number of quasielasticlines equal to the number of exponential terms in M(Q,t),(II) the Laplace transform of F(Q,t) can be written as a ra-tional function in the complex plane with a correspond-ing number of real, negative poles zj = zC,zD, ... plus twocomplex conjugate poles zA,B = -zs±iωs, and, finally, (III)the amplitudes Ij and Is of the various lines in (2) can beexplicitly calculated.The apparent similarity between the general line shape(2) and the hydrodynamic Rayleigh-Brillouin spectrum(1) is by no means coincidental, but simply reflects thefact that the development of the linearized-hydrody-namics treatment is equivalent to the assumption

(3)

where is the Q→0 limit of the

second frequency moment of the normalized spectrum

(4)

where the last equality is a well-known exact result [1].

If applied to the Q range of neutron or x-ray scattering,the RB triplet (1) does not correctly describe the experi-mental data. Such a failure is however to be expected, assoon as one remembers that (1) is derived under the hy-drodynamic assumption of very-long-wavelength excita-tions. The commonly adopted approach is then the for-mulation of different models for the memory functionthat may be able to account for the Q evolution of thecollective motions beyond hydrodynamics.As a first step, it appears quite natural to retain the samefunctional form for M(Q,t), but letting its parameters tovary freely with Q. This leads to the so-called “general-ized RB triplet” (GRB) lineshape [8], for which (2) stillhas the three-line structure of (1), but the various para-meters depend on Q differently from the hydrodynamiccase, and have to be determined by a best-fit procedure.The general parametrization of the line shape displayedin (2), common to all the most frequently used memoryfunction models, provides a full understanding of thedispersion curve of the sound excitations [8].The acoustic modes follow at each Q the dynamical be-haviour of a damped harmonic oscillator with character-istic frequency Ω = √zAzB and damping coefficientzs = -(zA + zB)/2. The actual oscillation frequency is thenωs = √(Ω2 - zs

2) as long as the oscillator finds itself in anunderdamped state, which occurs for Ω > zs. On the oth-er hand, if at some Q the condition is reversed (Ω < zs ),then an overdamping situation is obtained and thesound propagation is arrested. Such a condition is re-flected by the loss of oscillatory behaviour in the timedependence of F(Q,t), and by a modification of the spec-tral shape, where zA and zB become real and negativeand the Brillouin lines are transformed into Lorentziansof half widths -zA and -zB centred at zero frequency andsuperimposed onto the quasielastic lines.As examples of the application of the concepts just out-lined, we now briefly recall a few typical results for thecollective acoustic dynamics in very simple fluids.Argon is the prototype of a monatomic, classical, insulat-ing fluid, and it is an exceptionally convenient samplefor neutron studies due to the very large, totally coher-ent, scattering cross-section of the 36Ar isotope. A fullquantitative analysis of acoustic excitations in the liquidphase, carried out through fitting the GRB model for4 < Q / nm-1 < 38, was reported in the work of reference[9]. The resulting dispersion curve shows the so-called“propagation gap” of sound modes, that is the transitionfrom the under- to overdamping condition of the equiva-lent harmonic oscillator, shortly afterwards followed bya reverse transition restoring the propagating regime.Such a phenomenon may occur around Qp, i.e. the Q val-ue where the static structure factor displays a sharppeak, since S(Q) appears at the denominator in the ex-pression of Ω [8].

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This was the first observation of a propagation gap in areal fluid.Acoustic modes were also studied with neutron Bril-louin scattering in gaseous argon [10] at room tempera-ture and a pressure of 200 bar where, being the densitymuch lower, and therefore much higher, than in the liq-uid phase, low values of Q (in the range 0.1 ≤ Q ≤ 1)required the use of cold neutrons. At the lowest Q val-ues, the spectra agree with the RB line shape (1), butthey begin to deviate from it with increasing Q, reveal-ing the onset of non-hydrodynamic behaviour.In figure 1, the parameters Ω, zs and ωs of a GRB fit areplotted, both from the experiment and, for the sake ofcompleteness, from simulation results [11]. With respectto the predictions of RB theory, one can notice a slightlystronger upward curvature of Ω(Q) and a slightly small-er damping zs.

Then ωs = √(Ω2 - zs2) stays above the hydrodynamic dis-

persion curve, whose downward bending is effectivelycompensated, and a linear Q-dependence of the soundfrequency is found to persist beyond the strictly hydro-dynamic regime. Neutron Brillouin scattering has beenmostly applied to the study of monatomic systems suchas rare-gas fluids or liquid metals.Nonetheless, this technique can provide deep insight in-to the microscopic dynamics of molecular fluids too.Here we briefly recall some recent results obtained in thecase of liquid methane, in its deuterated form for neu-tron experimental convenience.In the range 2 < Q/nm-1 < 15, spectral data [12] wereanalysed by making use of the free-rotor approximation[13], so that it was possible to extract the centre-of-massdynamic structure factor. The parameters of the Brillouinlines were determined through the fitting of the GRB

model and successfully compared to those obtainedfrom a parallel analysis of MD simulations.However, the experimental data also served as a valida-tion of the potential function employed in the simula-tions, enabling a thorough study of the collective dy-namics in a much wider Q range, extending up to nearlyfour times the position Qp of the main peak of the staticstructure factor.This analysis of the carbon-carbon partial correlationspectra revealed new interesting features. Besides theGRB one, the so-called viscoelastic model line shapewas also employed for spectral fitting. This is definedby a memory function differing from the GRB one forthe presence of another exponential term replacing theδ-function, and leading to a line shape (2) with twoterms in the summation. This model, which thereforeprovides a spectrum with a central peak made of twoLorentzian lines, was shown to produce better fits forQ > 5 nm-1, revealing a transition from hydrodynamic-like to viscoelastic behaviour [8]. Moreover, it wasfound [14] that acoustic excitations persist up to high Q,though their contribution to the total spectral intensityis substantially reduced.Finally, the occurrence of a propagation gap in a narrowQ interval around Qp was again detected, for the firsttime in a molecular liquid, and a dispersion curve close-ly resembling that of liquid argon was found. It can thusbe concluded that, notwithstanding the obvious differ-ences between monatomic and molecular systems,methane behaves very similarly to the rare gases if thecentre-of-mass dynamics is considered.The CD4 experimental data provide, however, anotherkind of example of the application of neutron Brillouinspectroscopy to the investigation of fundamental prop-erties of condensed matter. In fact, without resorting tothe free-rotor approximation for the separation of thecentre-of-mass motions, a deep insight on the intermole-cular forces was obtained [15] through the comparisonof data and MD simulations at the level of the total dy-namic structure factor as probed by neutron scattering.This is related to the measured intensity via the double-differential cross-section

(5)

where the subscripts refer to which neutron scatteringlengths appear in each term. For the CD4 molecule, theincoherent contribution is

(6)

where Sα,self (Q,ω) is the self dynamic structure factor foratoms of species α = C or D.

Figure 1. GRB analysis of neutron (red, [10]) and MD (blue, [11]) data ongaseous 36Ar at 200 bar. Black lines are the corresponding calculationswith RB theory. Upper frame: Ω (dots) and zs (squares). Lower frame: ωs

(dots). In both frames, the straight green line csQ is also shown.

The coherent term

(7)

is expressed in terms of the (Ashcroft-Langreth [16]) par-tial dynamic structure factors, and contains contribu-tions from correlations of two different atoms, either onthe same or on different molecules. MD opens the accessto the direct evaluation of all S(Q,ω)’s involved, and tothe study of their dependence on the used potentialmodel.Four different potential models denoted by theacronyms TUT, SA, RP, and RMK [15], all defined assums of site-site interactions and therefore allowing, in

different ways, for a overall anisotropic intermolecularpair-interaction energy, were used in the simulations.Since the incoherent part (6) turned out to be little sen-sitive to the differences among the potentials, a reliableMD estimate of Sinc(Q,ω) was obtained and subtractedfrom the measured total S(Q,ω) to give an experimen-tal determination of the coherent part. This could becompared to the simulated ones, calculated through(7), with better sensitivity to the input potential (seefigure 2). The agreement is good in the whole Q and ωrange for the TUT case only, with SA and RP resultslooking similar to TUT ones at low and high Q only, re-spectively.The last model, RMK, provides poor agreement in allcases. If now the potential energy of specific configura-tions of the molecule pair is plotted as a function of thedistance rCC between the molecular centres, as done in

figure 3, one finds that the mutual orientation of themolecules where a vertex of one tetrahedron is opposedto a face of the other (“base-vertex”, bv) is such that theabove similarities in spectra correspond to close agree-ment between energy curves in either the medium-rangeattractive part or the repulsive hard-core region, mostlikely probed at smaller and larger Q values, respective-ly. This suggests that, on the time scale probed by the co-herent part of S(Q,ω), specific pair configurations can beshown to contribute with a larger weight to the observeddynamical behaviour.This kind of analysis reveals a higher sensitivity of dy-namical data to the potential function than what isfound from static structure measurements. Neutron Bril-louin scattering can then be used to carefully exploit thedirect access to microscopic interaction effects offered by

MD simulations. In conclusion, the investigation of col-lective dynamics in fluid systems is a very active researchfield, where many different kinds of liquids can now bestudied with the increased accuracy made possible bytechnical advances in spectroscopic instrumentation andcomputing power.Indeed, starting from the simplest systems such as rare-gas fluids and liquid metals, growing attention has beenshifted to molecular liquids, liquid alloys, metal vapours,molten salts and oxides, metals in solutions, and complexsystems.Fundamental dynamical properties such as the propaga-tion of sound modes, the characterization of dampingprocesses affecting both the quasielastic and the inelasticpart of the spectra, the wavevector dependence of relax-ation processes of either thermal or structural origin, andthe in-detail relationship of the whole dynamical behav-

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Figure 2. Coherent dynamic structure factor of liquid CD4 at selected Q values. Neutron data (black circles with error bars) are compared with the corre-sponding MD results for the SA (red line), RMK (green line), TUT (blue dots) and RP (pink line) potentials. In the right frame, the SA and RMK centralpeaks coincide.

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iour to the forces acting at the atomic level, are wide opento thorough investigations by means of radiation scatter-ing techniques, among which neutron Brillouin scatteringis promising to contribute in an essential way.

References1. U. Balucani, M. Zoppi, Dynamics of the Liquid State, Clarendon, Ox-

ford, 1994.2. P.A. Egelstaff, G. Kearley, J.-B. Suck, J.P.A. Youden, Europhys. Lett.

10, 37 (1989); J. Youden, P.A. Egelstaff, J. Mutka, J.-B. Suck, J. Phys.:Condens. Matter 4, 8945 (1992).

3. D. Aisa et al., Nucl. Instrum. Meth. Phys. Res. A, 544, 620 (2005).4. B. Dorner, H. Peisl, Nucl. Instrum. and Meth. 208, 587 (1983).5. F. Sette, G. Ruocco, M. Krisch, U. Bergmann, C. Masciovecchio, V.

Mazzacurati, G. Signorelli, R. Verbeni, Phys. Rev. Lett. 75, 850 (1995).6. C. Masciovecchio, A. Gessini, S.C. Santucci, J. Non-Cryst. Solids 352,

5126 (2006).7. P.A. Fleury, J.P. Boon, Phys. Rev. 186, 244 (1969).8. U. Bafile, E. Guarini, F. Barocchi, Phys. Rev. E 73, 061203 (2006).9. I.M. de Schepper, P. Verkerk, A.A. van Well, L.A. de Graaf, Phys. Rev.

Lett. 50, 974 (1983).

10. U. Bafile, P. Verkerk, F. Barocchi, L.A. de Graaf, J.-B. Suck, H. Mutka,Phys. Rev. Lett. 65, 2394 (1990).

11. U. Bafile, F. Barocchi, M. Neumann, P. Verkerk, J. Phys.: Condens.Matter 6, A107 (1994).

12. E. Guarini, U. Bafile, F. Barocchi, F. Demmel, F. Formisano, M. Sam-poli, G. Venturi, Europhys. Lett. 72, 969 (2005).

13. E. Guarini, J. Phys.: Condens. Matter 15, R775 (2003).14. M. Sampoli, U. Bafile, F. Barocchi, E. Guarini, G. Venturi, J. Phys.:

Condens. Matter, 2008, in press.15. E. Guarini, M. Sampoli, G. Venturi, U. Bafile, F. Barocchi, Phys. Rev.

Lett. 99, 167801 (2007).16. N.W. Ashcroft, D.C. Langreth, Phys. Rev. 156, 685 (1967).

Figure 3. Three significant configurations of methane dimers (sketched in the insets) and corresponding CD4-CD4 potential energy, in units of the Boltz-mann constant. Different curves refer to the RMK (green), TUT (blue), RP (pink), and SA (red) models, plotted as a function of the carbon-carbon (CC)distance. Positive energies above 100 K are plotted on a logarithmic scale.

AbstractThe experimental evidence for the presence of non-viscous flowin solid helium is described and compared with experiments onliquid helium. The physical origin of superfluid and possiblesupersolid flow is described. We outline the results of a recentneutron scattering experiment, searching for evidence of Bose-Einstein condensation in solid helium. No such evidence wasfound and it is inferred that supersolidity is not due to Bose-Einstein condensation in crystalline helium.

Experimental and theoretical work on liquid helium hasbeen responsible for the award of nearly 20 Nobel prizes.The fundamental interest in this system is due to its ma-nifestation of quantum mechanical effects over macro-scopic length scales. One remarkable property of super-fluid helium is that it has no viscous interaction withmacroscopic bodies, provided these are moved onlyslowly in the fluid. In a classic experiment Adronikash-villi [1] suspended a column of closely spaced disksfrom a fibre in a bath of liquid helium (fig 1a) and mea-sured the period of torsional oscillation as a function oftemperature T. He found that the period varied and in-ferred that below the superfluid transition a fraction ofthe atomic mass (the superfluid fraction ρS) does not ha-ve any viscous interaction with the fluid. In a fluid withnormal viscosity all the liquid between the disks is trap-ped and the mass of the torsional pendulum is the massof disk+fluid between disks. In the superfluid only afraction 1 - ρS(T) of the fluid is trapped – hence only this

fraction rotates as the disks rotate. The effective mass ofthe pendulum and the oscillation frequency therefore va-ries with T.By measuring the oscillation frequency Adronikashvilliwas able to determine ρS as a function of temperature(fig. 1b). Below about 1K the liquid is almost entirely su-perfluid. None of the fluid rotates with the disks and theperiod is the same as it would be in vacuum! In (2004)Kim and Chan [2,3,4] published the remarkable result

that if essentially the same experiment is performed onsolid helium, then a fraction of the helium mass similarlybehaves as a non-viscous fluid. In their measurement so-lid helium was frozen into an annular ring attached to aBe-Cu torsion rod (fig. 2a) and the resonant frequency ofoscillation was measured as a function of temperature.As in Adronikashvilli’s experiment, this frequency chan-ged with T. This was interpreted as being due to a su-persolid fraction of helium (also known as the “non-classical rotational inertia” fraction) which does not ro-tate when the container is rotated.At the lowest temperatures and smallest velocities ofoscillation (fig. 2b), this fraction is ~2%. These observa-tions have been confirmed by a number of independentgroups [5,6] although their theoretical explanation is stilluncertain. The possibility of flow without viscosity in so-lid helium was theoretically predicted more than 30years ago [7,8,9]. The latter predictions rely upon the oc-currence of Bose Einstein condensation (BEC) in the so-

Bose-Einstein Condensation and Supersolid HeliumJ. MayersRutherford Appleton Laboratory, Chilton, OX11 0QX, UK

Figure 1. (a) A column of closely spaced discs is suspended in a bath ofliquid helium from a torsional fibre. (b) From a measurement of the fre-quency of oscillation it is inferred that a fraction ρS of helium has no vis-cous interaction with the discs.

Figure 2. Experiment of Kim and Chan. (a) The resonant frequency of acell containing an annulus of solid helium is measured. (b) From the va-riation of this frequency with temperature it is inferred that a fraction ofthe mass of the frozen helium does not rotate with the container.

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lid and the aim of the neutron experiment described herewas to investigate whether BEC is also the cause of su-persolidity. When BEC occurs the momentum distribu-tion of the atoms develops a peak, centred at zero mo-mentum and with width ∆p~h- /L, where L is the lineardimension of the whole system (fig. 3).In liquid helium, neutron experiments show that theweight of this peak is ƒ = 0.07 ± 0.01 as T→0 [10,11]. Dueto the macroscopic size of typical samples (L~1cm), thecondensate peak in liquid helium is essentially a δ func-tion in momentum space.However its width is measurable in Bose condensedtrapped atomic clouds, for which L is typically a few mi-crons [12].The microscopic consequences of a momentum distribu-tion of the form shown in figure 3 can be understood by

consideration of the fundamental quantum-mechanicalexpression [13] for the momentum distribution of Nidentical particles. This is

(1)

where Ψ(r,s) is N particle wave function, r is the coordi-nate of one of the particles and s denotes the other N-1coordinates. Note that in a single particle system this ex-pression reduces to the well known expression for themomentum distribution in terms of the single particlewave function. It is a consequence of Fourier transformtheory that if n(p) contains a peak of width ∆p~h- /L, thenΨ(r,s) must be a “delocalised” function of r – that is non-zero over length scales ~L. This result is used in elemen-tary derivations of the uncertainty principle in single

particle quantum mechanics – the localisation in p spaceimplies a delocalisation in r space. It is also well knownin neutron scattering. The diffraction pattern is the squa-re of the modulus of the Fourier transform of the scatte-ring amplitude and the width of peaks in small-anglescattering or of Bragg peaks, is inversely related to thesizes of crystallites in powders or domain sizes in ma-gnetic materials. The physical nature of the delocalisa-tion of the wave function in a Bose condensed systemcan be illustrated using a simple model for the groundstate wave function of liquid 4He, introduced by Feyn-man [14] and used by Penrose and Onsager [15] for thefirst realistic calculation of the Bose condensate fractionin liquid helium.Liquid helium consists of impenetrablehard sphere atoms of diameter a = 2.56 Å with weak in-teractions between atoms.

Feynman modelled this behaviour by assuming that thewave function is zero if any two atoms havecoordinates|rn - rm|< a, but has the same value for allother configurations of atoms. The implied r dependenceof Ψ(r,s) for a given s is illustrated in fig. 4. Ψ(r,s) is zeroif r lies within a distance a of any of the other atoms(shown as black circles) and has the same value for allother values of r. It can be seen that Ψ(r,s) is indeed non-zero over length scales ~L, occupying the spacesbetween atoms in the liquid structure. The Feynman mo-del predicts that ƒ is equal to the fraction of the total vo-lume within which Ψ is non-zero. More generally it canbe shown that Ψ is non-zero within at least a fraction ƒof the total volume [16,17].A second fundamental property of the ground state isthat the phase of Ψ(r,s) is the same for all r. This is a fun-

Figure 3. Bose-Einstein condensation. A fractionf of the atoms occupy a central peak in the mo-mentum distribution, with a width ~h/L , whe-re L is the linear dimension of the entire system.

Figure 4. Illustrating the delocalisation of the wave function in Bose condensed liquid helium. Anytwo phase coherent points 1 and 2 must be connected by a path over which is non-zero (red line).This also implies the presence of connected macroscopic loops in a Bose condensed system, as illu-strated on the right

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damental result of quantum mechanics [18] – the phaseof the ground state wave function of any Bose systemhas no nodes and hence has a phase independent of bothr and s. In general phase coherence in the wave functionimplies connectivity. For example the phase of the wavefunction at point 1 in fig. 4a precisely determines thephase of the wave function at point 2. This implies that itmust be possible to trace a “connected” path through thefluid between these points- that is one over which Ψ(r,s)is always non-zero. This also implies that macroscopicconnected loops are possible as illustrated in fig. 4b. The delocalisation of the wave function has profoundconsequences for the macroscopic behaviour of Bosecondensed systems. Consider what happens if a fluiddescribed by such a wave function is stirred by a macro-scopic object such as the column of disks used byAdronikashvilli. In a normal viscous fluid this stirringwill create a macroscopic velocity field v(r). We considera particular arrangement s of particles and denote Ψ(r,s)as ψ(r) =|ψ(r)|exp[iφ(r)]. It follows from a Galilean tran-sformation that the creation of a macroscopic velocityfield v(r) will cause a phase change

φ(r) → φ0(r) + mv(r).r/h- (2)

The ground state phase φ0 is independent of and hencemust satisfy

(3)

If the wave function is to remain remains single valuedwhen the liquid is stirred – that is if BEC is maintained,its new phase must satisfy the equation

(4)

It follows from equations (2) to (4) that must satisfy

(5)

Since Ψ(r) is non-zero over macroscopic distances in thepresence of BEC, equation (5) must be satisfied over ma-croscopic loops. Macroscopic velocity fields set up bynormal viscous flow do not satisfy equation (5) – hencenormal viscous processes are not possible in the presen-ce of BEC. The only possibility for macroscopic flow isthe creation of quantised vortices.It follows from the classic argument of Landau [13] thatthere is a critical velocity vc = ε/p required for the crea-tion of any flow, where ε is the energy and p themomentum of the fluid flow. This critical velocity is zerofor normal viscous processes, but for the creation ofquantised vortices is typically a few cm/sec. Hence pro-vided the disks rotate slowly they cannot excite any ma-

croscopic flow in a Bose condensed system–the fluiddoes not move when the disks rotate and at T=0 there isno viscous interaction between the disks and the fluid.Hence the presence of BEC explains rather simply theresults of the Adronikashvilli experiment at low tempe-ratures. In solid helium the situation can in principle bequite similar. Figure 5 shows schematically a crystal con-taining many vacancies. Provided that there are suffi-cient vacancies, connected paths within the crystal canstill be present and the wave function can delocalisewithin the vacancies, allowing the presence of BEC.It is very counterintuitive for significant mass flow to oc-cur at all in a solid. To explain how this can occur withina Bose condensed solid we consider a simplified versionof an argument given by Leggett [9]. We consider solidhelium in its ground state contained in a thin ring of ra-

dius R. Assuming that the solid is connected in the sensejust discussed, the phase of the wave function can be in-tegrated around the entire ring. Since the phase of theground state is constant, equation (3) is satisfied whenthe ring is stationary. It is assumed that at sufficientlylow velocities of rotation, this condition is maintained. Itfollows from mathematical transformation of the Schrö-dinger equation that in a frame of reference rotating withthe ring (the “ring frame”) equation (3) is equivalent to

(6)

Figure 5. Schematic illustration of a crystal of helium, containing manyvacancies. Macroscopic loops over regions where Ψ(r,s) is non-zeroare possible.

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where φΩ is the phase in the ring frame and∆φR = (m/h- )(2πR)2Ω.For a very thin ring equation (6) reduces to the one di-mensional expression

(7)

where x is the distance around the ring. The flow in thering frame is given by standard quantum mechanics as

FR(x) = h

-_mψ(x)2 dφ

R/ dx = ψ(x)2 v

R(x) (8)

where vR(x) is the velocity of flow. Hence condition (3) inthe laboratory frame, which is necessary for BEC to bemaintained, implies that in the ring frame

(9)

In order to illustrate the basic principles of the argumentwe assume a simplified model for ψ(x) in which ψ(x) hasonly two values; √ρ1 over 50% of its domain and √ρ2 inthe other 50%. Since the solid is rigidly attached to thewalls one would expect that its structure in the framemoving with the ring is constant in time. If the structureis crystalline for example, the lattice sites will rotate withthe ring. However equation (9) implies that there is alsoa flow of mass in the ring frame. These two conditionsare compatible provided the flow in the ring framemaintains a constant distribution of mass density - thatis providing

ρ1v1 = ρ2v2 (10)

Equations (8)- (10) imply that

(11)

Consider the limiting forms of this expression: whenρ2 → 0, F → 0 , and there is no flow in the ring frame.This is “normal” behaviour - all the mass of the heliumrotates with the ring.This limit also demonstrates that supersolid flow can oc-cur only if the wave function is connected. In contrast ifρ1 = ρ2 the flow has a maximum value, corresponding tonone of the mass rotating with the ring and 100% super-solidity. A very important point is that the size of the su-persolid fraction is not related to the size of the condensa-te fraction. The supersolid fraction is determined by theminimum amplitude of ψ(x), whereas the condensatefraction is determined essentially by the volume of the re-

gions where ψ(x) has large amplitude. In the limit ρ2 → 0,the model gives a superfluid fraction of zero and a con-densate fraction of 50%!Although this model is idealised, its main implicationsapply to other wave function describing a Bose conden-sed solid. The value of the supersolid fraction is determi-ned by the bottlenecks to flow, where the wave functionhas small values.The fact that the measured supersolid fraction in solid he-lium is only ~2%, does not necessarily imply a small con-densate fraction. The condensate fraction is always smal-ler than the superfluid fraction in the liquid, but in thesolid, ƒ can be either smaller or greater than the superso-lid fraction.In fact the necessity for the wave function to be connec-ted suggests that there must be many vacancies – random

vacancies in a crystal structure provide a connectednetwork only at vacancy concentration 15-20%. Accor-ding to the Feynman model of the wave function thiswould imply a condensate fraction also 10-15%. In the li-quid it has been argued [19,20] that the spaces in the li-quid structure, necessary for the presence of BEC, deve-lop when BEC occurs.The development of these spacesis responsible for unique behaviour observed in super-fluid helium [21,22] – pair correlations decrease as thetemperature is lowered.Just as vacancies in a crystal structure remove intensityfrom Bragg peaks and add diffuse intensity, spaces in a li-quid structure remove intensity from the peaks in S(q) andadd intensity between peaks. This reduces the contrast inS(q) oscillations and hence measured pair correlations asthe temperature is lowered and spaces in the structure in-crease. The aim of the ISIS experiment was to try and de-termine whether BEC is the cause of supersolidity by sear-

21

21

ρρρρ

πφ

+

∆=

Rm

hF

Figure 6. Schematic diagram of ex-periment on the VESUVIO instru-ment at ISIS.

ching for these two signatures of BEC, observed in thefluid: (1) a drop of ~10% in the atomic kinetic energy; (2)an increase of ~10% in the vacancy concentration. Threedifferent samples were prepared to test the effects of cry-stal quality and 3He impurity concentration, which arethought to be important for the observation of supersoli-dity [3, 23]. Sample A was a single crystal prepared fromhigh purity (~0.3 ppm 3He) 4He gas.Sample B was a high purity polycrystal obtained byrapid cooling and sample C a polycrystal containing10 ppm of 3He. The experiment [24] was performed onthe VESUVIO spectrometer, illustrated schematically inFigure 6.VESUVIO is an inverse geometry spectrometer withenergy analysis performed using the filter difference te-chnique. Two measurements are performed; the first

with a thin gold foil placed between the sample and thedetectors and the second with the foil removed. The foilabsorbs neutrons strongly within a narrow window cen-tred at 4.9±0.1 eV. By taking the difference between thefoil in and foil out measurements (Figure 7) one effecti-vely detects only neutrons absorbed by the foil.The very large final energy allows time of flight measure-ments with energy transfers in the range 1-100 eV andwave vector transfers 40-150 Å-1. At such large energyand momentum transfers the impulse approximation(IA) [25, 26] can be used to interpret data.According to the IA, neutrons scatter from single nucleiwith conservation of momentum and kinetic energy ofthe neutron+nucleus. This implies that the energy tran-sfer h- ω is given by

h- ω = (p + h- q)2

– p2___

2M 2M (12)

Where q is the wave vector transfer in the measurement,p is the momentum of the struck atom before the colli-sion and M is the atomic mass. Rearranging this equa-tion gives

y = p.q = M__q ω -

h- q2___2M (13)

Thus by measuring ω and q, the component of the ato-mic momentum along the unit vector q (conventionallydenoted as y) can be determined for each individualscattering event.By measuring a very large number of such events, theprobability distribution J(y) of values can be determined.Figure 8 shows data from all detectors in a single run af-ter binning in the space corresponding to mass 4. After

subtraction of the background signal from the samplecontainer we obtain for the helium sample (Figure 8b).In an isotropic system the mean kinetic energy of theatoms can be calculated from

κ = 3h- 2___2M

y2 J(y) dy (14)

For a Gaussian J(y)

(15)

and κ = 3/2 h- 2σ2/M .The data was analysed by fitting equation (15) convolvedwith the instrument resolution function. The latter wasdetermined by fitting to liquid data collected at a tempe-

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Figure 7. Illustrates the filter difference technique employed onVESUVIO. Two measurements are taken; one with a gold filter be-tween the sample and detectors (blue line) and one with the foil re-moved (red line). The difference (black line) is the “raw” time offlight data analysed in the experiment.

Figure 8. (a) Shows summed time of flight data from all 92 detectors after bin-ning according to the value of y calculated for mass 4. The solid line is the sumof all fits to individual detectors. (b) Shows the data after subtraction of the con-tribution from the can+cryostat. The dotted line is the instrument resolutionfunction.

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rature of 2.5 K for which κ = 15.8 K [11]. The peak posi-tions are determined by the kinematics of the scatteringprocess via equation (12). Hence the fitting parametersare a Gaussian standard deviation and amplitude for ea-ch peak. In each run the Gaussian standard deviation σ ofthe He peak was determined for each of the 92 detectors.Figure 9 shows a typical data set with the individual σvalues shown as a function of scattering angle. A very re-laxed energy resolution (see Figure 8) was employed inorder to increase the statistical accuracy of the measure-ments. Despite the rather poor resolution, which rulesout any detailed line shape analysis, kinetic energies canbe obtained quite accurately by this procedure.A VESUVIO measurement on liquid helium [27] usingthe same technique showed a sharp change in the atomickinetic energy of ~10% at the superfluid transition and

quite accurately reproduced calculated and previouslymeasured values of κ. The σ values and the correspon-ding kinetic energies obtained in each run were obtainedby performing a weighted average over the κ values ob-tained from individual detectors.The results with statistical errors are shown in Figure 10and within error show no change through the tempera-ture range where the supersolid fraction develops. TheVESUVIO detectors allow the simultaneous collection ofdiffraction patterns from the sample. These were used todetermine the lattice spacings for the three samples.The results are given in table 1. The errors on the latticespacings were the standard deviations of the determina-tions from the Bragg peaks observed in different detec-tors. For sample A the (101) peak was observable only in2 detectors, the (100) peak in a single detector and (002)

Figure 9. Values of obtained from individual detectors for sample A at0.400K as a function of scattering angle.

Figure 10. Kinetic energies for different runs. The open circles are resultsfrom sample A. The cross from sample B and the solid square from sample C.

Sample (101) (002) (100) Atoms/nm3 Molar Volume (cm3)

A (0.115K) 2.759 (7) 3.1055 31.2 (3) 19.3 (2)

A (0.400K) 2.759 (7) 3.1055 31.2 (3) 19.3 (2)

A (0.150K) 2.758 (7) 3.1056 31.2 (3) 19.3 (2)

A (0.070K) 2.758 (7) 3.1055 31.2 (3) 19.3 (2)

B (0.075K) 2.758 (2) 2.934 (4) 3.131 (2) 30.6 (3) 19.7 (2)

C (0.075K) 2.757 (3) 2.940 (3) 3.128 (2) 30.6 (3) 19.7 (2)

Table 1. The three longest lattice spacings in Å observed in the different runs. Column 5 contains the calculated sample density and column 6 the corre-sponding molar volume.

was not observed at all. The absolute value of the d spa-cing of the (100) peak in sample A is uncertain to ~1%,due to the finite width of the detectors. To within 1 partin 2000 no change in the lattice parameters was observedas the temperature was changed in sample A. The datapresented here should be compared with similar data onsuperfluid helium. In the latter case experiment [10, 11]shows that the kinetic energy decreases by 11-12% as thetemperature is lowered through the superfluid transi-tion. This is associated with the development of a 7-8%Bose condensate fraction with zero kinetic energy. Neu-tron [21, 22] and X-ray [28] diffraction also show a signi-ficant change in structure as the liquid is cooled throughthe superfluid transition. The liquid becomes more di-sordered, consistent [16, 17] with the development of~10% more spaces in the liquid structure. In contrast themeasurements presented here imply that the vacancyconcentration does not change to within ~0.1% as the so-lid is cooled through the supersolid transition region.The sample was maintained at constant density and anygreater change in vacancy concentration would have gi-ven a measurable change in the lattice parameter. Inconclusion the measurements show that Bose-Einsteincondensation in crystalline solid helium is probably notresponsible for supersolidity.This conclusion is supported by recently published neu-tron measurements on the MARI spectrometer at ISIS,which show that the Bose condensate fraction in solidhelium is zero to within 1% [29]. The microscopic originof supersolidity is still unclear. Recent measurements[30] have shown that the supersolid fraction is signifi-cantly reduced by annealing and it has been suggestedthat supersolidity could be due to the presence of a glas-sy phase of solid helium, obtained by rapid cooling [31].In order to investigate this possibility we plan toperform an in-situ measurement of the supersolid frac-tion with an arrangement similar to that shown in Figure2a and accurately measure the helium neutron diffrac-tion pattern in the presence and absence of supersolidity.If successful this measurement would make a vital con-tribution towards the understanding of the puzzlingphenomenon of supersolidity.

References1. E.L. Andronikashvili, J. Phys. (USSR) 10, 201 (1946)

2. E. Kim and M.H.W. Chan, Nature (London) 427, 225 (2004)

3. E. Kim and M.H.W. Chan, Science 305, 1941 (2004)

4. E. Kim and H.W. Chan, Phys. Rev. Lett. 97, 1153025. A.S. Rittner and J.D. Reppy, cond-mat/06045286. K. Shirahama et al., http://online.kitp.ucsb.edu/online/smatter_m06/

shirahama/

7. A.F. Andreev and I.M. Lifshitz, Sov. Phys. JETP 29, 1107 (1969)8. G.V. Chester, Phys. Rev. A 2, 256 (1970)9. A.J. Leggett, Phys. Rev. Lett. 25, 1543 (1970)10. T.R. Sosnick, W.M. Snow and P.E. Sokol Phys. Europhys. Lett. 9, 707 (1989)11. R.T. Azuah, W.G. Stirling, H.R. Glyde, M. Boninsegni, P.E. Sokol,

S.M. Bennington, Phys Rev. B 56, 14620 (1997)12. J. Stenger et al., Phys. Rev. Lett. 82, 4569 (1999)13. L. Landau and E.M. Lifshitz, Statistical Physics, 3rd ed. (Pergamon,

New York, 1978), pp. 192–19714. R.P. Feynman, Phys. Rev. 91, 1291 (1953)15. O. Penrose and L. Onsager, Phys. Rev. 104, 576 (1956)16. J. Mayers, Phys. Rev. Lett. 84, 314 (2000)17. J. Mayers, Phys. Rev. B 64, 224521 (2001)18. K. Huang, Statistical Mechanics, 2cnd Edition, (John Wiley and Sons,

New York 1987), Appendix 1.19. J. Mayers, Phys. Rev. Lett. 92, 135302 (2004)20. J. Mayers, Phys. Rev. B 74, 014516 (2006)21. V.F. Sears and E.C. Svensson, Phys. Rev. Lett. 43, 2009 (1979)22. E.C. Svensson, V.F. Sears, A.D.B. Woods and P. Martel, Phys. Rev. B 21,

3638 (1980)23. S. Sasaki et al., Science 313, 1098 (1997)24. M.A. Adams, J. Mayers, O. Kirichek and R.B.E. Down, Phys. Rev. Lett.

98, 085301 (2007)25. See H.R. Glyde, Phys. Rev. B 50, 6726 (1994) for a recent review of the

literature on the validity of the IA26. J. Mayers, Phys. Rev. B 41, 41 (1990) gives a very simple derivation of

the IA27. J. Mayers, F. Albergamo and D. Timms, Physica B 276, 811-813 (2000)28. H.N. Robkoff, D.A. Ewen and R.B. Hallock, Phys. Rev. Lett. 43, 2006

(1979)29. S.O. Diallo, J.V. Pearce, R.T. Azuah, O. Kirichek, J.W. Taylor and

H.R. Glyde30. A.S. Ritner and J.D. Reppy, Phys. Rev. Lett 98, 205301 (2007)31. A.V. Balatsky, Z. Nussinov, M. Graf and S. Trugman, Phys. Rev. B 75,

094201, (2007)

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Protons on target!The ISIS Second Target Station Project at the UK Ruther-ford Appleton Laboratory in Oxfordshire achieved a ma-jor milestone on Friday 14 December, at the first attemptand two days ahead of schedule. Protons were successful-ly extracted into the new proton transfer beamline fromthe existing ISIS accelerator and delivered to the new tar-get station. During the test, bunches of protons travellingat 84% of the speed of light were transferred from the cir-cular ISIS synchrotron accelerator into the 143m long pro-ton beamline. They were guided by a sequence of 57steering and focusing magnets onto a graphite test targetlocated inside the new target station. The arrival of theprotons was detected by measuring the electrical currentinduced in the target and the beam profiles along thelength of the beam line were checked. “This is a fantasticachievement and a major milestone towards realising thesuccessful operation of the second target station andopening up new possibilities for science research in theUK,” said ISIS Director Dr. Andrew Taylor. “Following afive year construction schedule, the project continues tobe on time and on budget and we are expecting our firstneutrons in June 2008.” The £140 million ISIS Second Tar-get Station will double the capacity of the world-leadingISIS research centre and significantly increase its capabili-ty for nanoscience applications. As part of the muchneeded expansion of facilities at the Rutherford AppletonLaboratory to meet modern research challenges, the newtarget station will keep European scientists at the fore-front of materials research. It will enable breakthroughs

to be made that will underpin the next generation of su-per-fast computers, data storage, sensors, pharmaceuticaland medical applications, materials processing, catalysis,biotechnology and clean energy technology.

Getting ready for neutronsThe pace of progress in building the Second Target Sta-tion during 2007 has been impressive. Substantial quanti-ties of equipment have been installed and commissionedin preparation for the ISIS target station to generate itsfirst neutrons for initial experiments in Spring 2008. Dur-ing the summer months, several major milestones wereachieved by the project. The 6000 tonne steel and concretemonolith structure to house the neutron target was com-pleted, and the proton beamline stretching from the syn-chrotron to the target station was installed. Cryogeniccooling systems for the neutron target assembly passedtheir performance tests in France and were delivered tothe site. The beryllium reflector to surround the targetand increase neutron yield was delivered from the UnitedStates. Instrument shielding rooms have been constructedand the large vacuum tank for the Sans2d instrument is inposition. Components for the Offspec reflectometer de-veloped in collaboration with the Technical University ofDelft have been successfully tested with neutrons. In De-cember 2007, the first lengths of supermirror neutronguide for the Wish diffractometer were installed. The ex-perimental programme on the seven new neutron instru-ments will begin in Autumn 2008 and the new neutronsource is expected to operate for at least 20 years.

ISIS Second Target Station ProjectM. BullISIS Spectroscopy & Support Div., Rutherford Appleton Lab.

All Image Credits: Stephen Kill for ISIS, Science and Technology Facilities Council.

Friday 14 December 2007 14:57: Members of the ISIS Sec-ond Target Station Project celebrate the successful deliveryof protons along the new proton transfer beamline.

A 6000 tonne steel and concrete structuresurrounds the new neutron source. Highenergy protons strike a tungsten target atthe centre to release neutrons for experi-ments.

Proton bunches travel at 84% of thespeed of light along the proton beamlineto the new target station.

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Diamond Light Source is the UK’s new 3rd Generation3GeV synchrotron, with high brightness and low emit-tance (2.54 nmrad). The facility, which began operatingin January 2007, is co-funded in a joint venture by theUK Government (86%) via the Science and TechnologyFacilities Council, and the Wellcome Trust (14%), one ofthe largest biomedical charities in the world. Followingthe first two calls for proposals from the user communi-ty, Diamond received in excess of 300 applications forbeamtime, of which just over 100 have been allocated ex-perimental time at the facility.

Machine parametersThe machine’s linac gives the electrons an energy of100MeV. Diamond’s booster synchrotron is 158m in cir-cumference and here the electrons are accelerated to3GeV before being injected into the storage ring which is561.6m in circumference.The main parameters of Diamond’s accelerators areshown below:

In January 2007, the first seven Phase I beamlines be-came operational. These beamlines all operate with In-sertion Devices as the source. These were installed be-fore 3 GeV commissioning began in September 2006 andan eighth device (I22) was installed in the Dec./Jan.shutdown. Six of these are in-vacuum devices, one is anAPPLE-II helical undulator and one is a multipole su-perconducting wiggler. The following table summarisesthe main properties of these devices. All of the insertiondevices have been commissioned and are in routine use;the in-vacuum devices are currently operating down tothe initial minimum gap of 7 mm. Trim coils are set au-tomatically as a function of ID gap (and phase in the caseof the HU64 device) and keep the closed orbit within 1-2µm rms. Other effects of the devices on the beam aresmall, and so far do not need correction. No effects onlifetime have been observed.

Phase I BeamlinesThree of the first phase of beamlines are for Macromolec-ular Crystallography, and provide state-of-the-art facili-ties for X-ray data collection on biological macromole-cules with emphasis on precision, accuracy, automationand high throughput. These beamlines are tunable overthe wavelength range 0.5 - 2.5 Å, to enable Multiwave-length Anomalous Diffraction (MAD) experiments to becarried out. All three beamlines are optimised for per-formance around 0.98 Å to enable MAD experiments atthe Se K-edge at 0.979 Å. Robotic systems for automatedsample handling and crystal centring, and software al-lowing automated data collection mean these beamlines

Experiments underway at UK’s new synchrotronS. Damerell and S. FletcherDiamond Light Source

Linac

Energy 100 MeV

Repetition rate 5 Hz

Booster

Circumference 158.4 m

Energy (injection, extraction) 100 MeV, 3 GeV

Emittance 141 nm rad

Repetition rate 5 Hz

Storage Ring

Energy 3.0 GeV

Circumference 561.6 m

No. of cells 24

Free straight lenghts for IDs 18x5 m, 4x8 m

Electron beam current 300 mA (500 mA planned)

Minimum beam lifetime 10 hours (top-up planned)

Emittance (horizontal, vetical) 2.7 nm rad, 0.03 nm rad

Table 1. Main parameters of Diamond’s accelerators

Figure 1. Diamond Light Source

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are highly efficient. Facilities for remote monitoring andbeamline operation further enhances performance, andthe implementation of biological containment at catego-ry 3 level on beamline I03 will allow category 3pathogens to be studied. The Nanoscience beamline is amicrofocus soft-X-ray beamline for X-ray photoelectronmicroscopy, exploiting the brightest region in Diamond’sspectrum. It combines microfocused soft X-rays withvariable linear and circular polarization and X-ray pho-toelectron emission microscopy (PEEM) to provide spec-troscopic data on nanometre length scales. The intensepolarised beam can be focused to a spot several micronsin diameter, allowing the PEEM to probe nanomagnet-ism and nanostructures. It is possible to perform photoe-mission and absorption measurements at nanometrespatial resolution, with an energy resolution of less than300 meV. The Extreme Conditions beamline provides bothwhite and monochromatic high-energy X-rays in bothfocused and unfocused mode into the 100 keV range fordiffraction experiments. The intense very high-energy X-rays can penetrate into complex sample assemblies, andcan be collimated to a few µm, permitting detailed map-ping of structural order or disorder, chemical finger-print, or single crystal structure determination. A dia-mond anvil cell enables precision control of pressures in-

to the 100 GPa regime. Similarly cryogenic cooling, resis-tive heating and heating with IR lasers allow controlledtemperature environments from a few Kelvin to up to5000 K. The Materials and Magnetism beamline is auniquely versatile X-ray diffraction and scattering facili-ty. The intense, low-divergence undulator beam is fo-cused to a spot less than 100 x 400 µm, with an energyrange that is continuously tuneable from 3.4 keV (just

below the uranium M-edges) to around 20 keV. Easily re-movable focusing optics enable the beamline to meet thedisparate requirements for small focal spots and veryhigh resolution diffraction and coherence. A set of re-motely interchangeable crystals in the monochromatorenable the beam parameters to be matched to the samplequality and a diamond crystal phase retarder is used toselect the required polarisation state (circular, linear orelliptical). The Microfocus Spectroscopy beamline useshigh-brightness sub-micron X-ray beams for the study ofcomplex inhomogenous materials and systems under re-alistic conditions.The combination of the brilliance of the third generationsynchrotron source, and optics able to focus the beam toa micron sized spot, allows compositional, temporal andspatial information to be gathered at high resolution.It provides a total energy range of 2-20 keV with a coreenergy range of 5 - 13 keV, and allows scanning EXAFSto k > 12 A. It has a spatial resolution of 1 µm2 with aspectral resolution of 10-4.

Phase II BeamlinesIn addition to the Phase I beamlines, Diamond has fund-ing in place to construct fifteen Phase II beamlines, thefirst of which, the Non-crystalline Diffraction beamline,

has been built and welcomed its first users in August2007. The remaining fourteen will go into operation atthe rate of around four each year.The Phase II investment will also exploit the high bril-liance of the source for imaging and determining thestructures of larger biological structures, such as viruses,and will include the first UK beamlines exploiting coher-ence of the X-ray source. It will also establish support

Table 2. Details of Diamond’s first beamlines and insertion devices

Beamline Source Period No. Field[mm] of Periods gap= gap=

5mm 7mm

Macromolecular Crystallography (I02) In vacuum 2m U23 undulator 23 85 0.92 0.70



Nanoscience 2 x APPLE-II HU64 helical undulators 64 2 x 33 0.94T (15 mm)

Extreme conditions 3.5T superconducting multipole wiggler 60 24 3.5T

Materials & Magnetism In vacuum 2m U27 undulator 27 73 1.0 0.8

Microfocus Spectroscopy In vacuum 2m U27 undulator 27 73 1.0 0.8

Non-crystalline Diffraction In vacuum 2m U25 undulator 25 79 0.97 0.75


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labs, adjacent to the beamlines – bringing a holistic viewto an overall scientific facility. Phase II also provides fora detector development programme to ensure that thebrilliance of Diamond is fully exploited. This detectorprogramme will also have a significant benefit for theoperation of some of the Phase I beamlines by extendingtheir capability and deliver a greater return on the initialinvestment. The Phase II beamlines will use a mixture ofInsertion Devices and Bending Magnets as their source.

To keep up to date with developments at the DiamondLight Source, please visit: www.diamond.ac.uk A research expertise booklet has just been published toenable outside researchers to identify science expertise atDiamond, download at:www.diamond.ac.uk/Publications/SciencePubs

Figure 1. In addition to the Phase I beamlines, Diamond has funding in place to construct fifteen Phase II beamlines, the first of which, the Non-crystal-line Diffraction beamline, has been built and welcomed its first users in August 2007. The remaining fourteen will go into operation at the rate of aroundfour each year.

Figure 2. Storage Ring

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AbstractThe BaD ElPh (Band Dispersion and Electron-Phonon cou-pling) beamline has been commissioned at the ELETTRA syn-chrotron radiation laboratory. It is the branch-line of the IUVSbeamline and exploits the same Figure-8 undulator. The beam-line is based on a normal incidence monochromator and coversthe photon energy range 4.7-40 eV with three gratings. Thebeamline is combined with an end-station for high-resolutionangle-resolved photoemission spectroscopy. The system is inparticular well suited for measurements of the electronic bandstructure, electron-phonon interaction, and thermally (or dop-ing) driven phase transitions in low dimensional systemscharacterized by large (≥ 7 Å) unit cell parameters.

From the late 1980s, Angular Resolved PhotoemissionSpectroscopy (ARPES) has been intensively applied toprobe the quasiparticle and the electronic structure belowthe Fermi level in solid materials. Thanks to the improve-ment in the energy and angular resolution of the electronspectrometers in the last decade, ARPES has been provedto be a powerful technique to reveal more subtle detailsin the spectral function of complex solids, like for in-stance superconductors, colossal magnetoresistive oxides,non-linear optical crystals, charge density wave com-pounds, metal-insulator transition systems, etc. [1-3]. Inthis paper we present a new undulator-based synchrotronradiation beamline at the ELETTRA storage ring nowavailable to the users community. The BaD ElPh beamlineis dedicated to high-resolution photoemission experimentin the low photon energy regime (4.7-40 eV). In such con-dition the best sensitivity to k-vector of photoemittedelectrons and high energy resolution is available. Samples

with very large Brillouin zone are welcome. Moreover,the inelastic electron mean free path is expected to in-crease drastically in the kinetic energy range < 10 eV al-lowing “bulk” sensitive measurements. The radiationsource of the BaD ElPh beamline is a Figure-8 undulator[4,5] shared with the IUVS beamline.This undulator is made of six periodic magnetic arrays:the central rows generate a vertical field with spatial peri-od λ, while the side blocks create a horizontal field withtwice that periodicity (2λ). The resultant electron trajecto-ry follows a figure-of-eight pattern when projected on thetransverse plane. Due to the opposite helicity in any twoconsecutive periods, the net polarization of the emitted

photons is linear at any observation angle. However, theradiation spectrum is composed of two sets of harmonics,conventionally defined by integer (i=1,2,3,…) and half-in-teger (i=1/2,3/2,5/2,…) indices and having alternativelyhorizontal (i=1,2,3,...) and vertical polarization direction.This undulator has 32 periods of NdFeB magnets with a140 mm period length and it provides the maximum pho-ton flux in the range 5 to 10 eV (about 1015 photon/s) [6].A schematic layout of the beamline is shown in Figure 1.The beamline is based on a 4-m-long Normal IncidenceMonochromator (NIM) with a constant included angleof 5°. NIMs offer the highest resolving power [7] but thephoton energy range is restricted to a maximum of about40 eV. The beamline consists of a silicon switching mir-ror to transfer the photon beam in the BaD ElPh or IUVSbeamline, a spherical pre-focusing mirror which focusesthe beam into an entrance slit, a NIM, a moveable exitslit, and a gold coated toroidal mirror which re-focuses

BaD ElPh: a new beamline for band dispersion andelectron-phonon coupling studies at ELETTRAP. Vilmercati, M. Barnaba, L. Petaccia, A. Bianco,D. Cocco, C. Masciovecchio, A. Goldoni

ELETTRA Synchrotron Light Laboratory, Sincrotrone TriesteS.C.p.A., S.S. 14 Km 163.5, 34012 Trieste, Italy

Figure 1. Layout of the BaD ElPh beamline. See text for details.


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the beam onto the sample. The monochromator has twointerchangeable spherical gratings with laminar profileto cover energy ranges of 4.7-11 eV (1500 l/mm, AlMgF2

coated) and 10-22 eV (3000 l/mm, SiC) at 2.0 GeV ofelectron ring energy. A third spherical grating to provide

photons in the energy range 20-40 eV (3000 l/mm,blazed profile, Pt coated) has been ordered and will beinstalled in the first semester of 2008. When ELETTRAoperates at 2.4 GeV the lowest photon energy availableis 6.7 eV. The pre-focusing mirror has two different coat-ings: Si for the 4.7-11 eV energy range and Pt for higherphoton energies.The entrance slit to grating distance is 3820 mm whilethe lowest exit slit to grating distance is 4070 mm. Theexit slit can be moved by 120 mm in order to keep the slitin focus over the energy ranges of the three gratings. Theaperture of both slits can be set in the 10-500 µm range.The groove profile of the gratings were designed to opti-

mize the first order diffraction efficiency and optimumsecond order suppression. The calculated absolute effi-ciency and total resolving power (E/∆E) of the BaD ElPhnormal incidence spherical grating monochromator areshown in Figure 2.The flux through the beamline was estimated using anAXUV-100 photodiode, which can be inserted into thebeam after the toroidal re-focusing mirror. The calculat-ed typical quantum efficiency of the photodiode hasbeen taken into account. With a pinhole angular accep-tance of 0.6×0.6 mrad2, an entrance slit aperture of 300µm, and with 200 mA accumulated in the storage ring(see Fig. 3a) the maximum photon flux, reached between7.5 and 9.5 eV in first harmonic, is about 3×1012 pho-tons/s on the sample with the exit slit open at 150 µm,while at 5 and 10.5 eV it decreases at about 2×1012 pho-tons/s. For the medium-energy grating the maximumflux is reached at 19 eV: the photon flux is 7×1011 pho-ton/s with the exit slit open at 300 µm. In the above con-ditions the calculated total resolving power of the beam-line is about 3000 at 8 eV and 2000 at 19 eV of photon en-ergy. Photoemission measurements suggest that the sec-ond order flux from the medium-energy grating is rela-tive high in the 12-15 eV range. Indeed, a later atomicforce microscopy (AFM) characterization has shown thatthis grating has not the optimum profile. We are nowconsidering to replace this grating with a new one froma different company, Carl Zeiss GmbH. The experimen-tal end station consists of two independent ultra-highvacuum (UHV) chambers and a simple load-lock cham-ber. The preparation chamber is equipped with an ionsputter gun and with several free flanges to mount theneeded tools for UHV in-situ growth of thin films. Inthis chamber a XPS apparatus (x-ray source and 100 mmhemispherical electron energy analyzer) is present too, inorder to perform chemical analysis of the sample. Themain experimental chamber is made in mu-metal formagnetic shielding and houses the electron energy ana-lyzer, a low-energy electron diffraction optics (Omicron,SpectaLEED), a high intensity vacuum ultraviolet source(Omicron, HIS 13), and a residual gas analyzer (StanfordResearch Systems, RGA 200). The manipulator has 4 de-gree of freedom (three translations and the polar angle).The sample holder can be transferred and is mounted ona cryostat (Advanced Research Systems, Helitran LT-3M)that reaches with liquid helium a temperature lowerthan 10 K. The sample temperature can be measured bya K-type thermocouple or by a chromel-AuFe thermo-couple connected to a Lake Shore 311S-T2 temperaturecontroller. To improve the reliability of the readings atlow temperatures we have used a silicon diode to cali-brate both the thermocouples. To perform ARPES experi-ments, the actual electron energy analyzer in the mainexperimental chamber is a Scienta SES 50 (courtesy of R.

Figure 2. Calculated (a) absolute efficiency and (b) total resolvingpower of the BaD ElPh normal incidence spherical grating monochro-mator. The total resolving power was calculated for three different slitapertures.

Claessen, University of Wuerzburg, Germany) mountedon a two axis goniometer in the vacuum chamber itself.Using a small analyzer necessarily means making sacri-fices in terms of overall flux. However, with this kind ofset-up, the k||-vector of the outgoing electrons can be se-

lected by moving the analyzer or the sample angles andit is possible to determine the polarization dependenceof certain photoemission features by changing both thesample and the spectrometer angles such that the anglebetween the incoming light and outgoing electrons ischanged, keeping constant the emission angle of theelectrons with respect to the sample normal. The totalexperimental energy resolutions, obtained by measuringthe Fermi edge of a molybdenum polycrystal at various

temperatures, are shown in Figure 3b. The best energyresolution reached is 5.9 meV with the pass-energy (PE)of the analyzer sets to 1 eV. The maximum angular ac-ceptance of this analyzer is about ±3° and the angularresolution is ≈0.1°. As all the Scienta analyzers, the SES50 is forced to work at PE KE, where KE is the kineticenergy of the photoelectrons, in order to avoid distortionof the angular and energy dispersions on the two-di-mensional (2D) detector. However, to satisfy this condi-tion, the spectrum acquisition time can become verylong especially working with low energy photons at lowKE of the photoelectrons. In order to improve the dataacquisition, now limited by the low transmission of theSES 50, and to extend the maximum angular acceptanceof the analyzer we have decided to employ an alterna-tive and most common set-up for ARPES: a large hemi-spherical electron energy analyzer mounted in a fixedgeometry on the experimental chamber. The large di-mension of the analyzer enables the achievement of hightransmission and resolution simultaneously.In the beginning of 2008 a new electron energy spec-trometer, a SPECS Phoibos 150 with a 2D CCD detectorsystem, is scheduled to be installed on a new main ex-perimental chamber of the BaD ElPh end-station to pro-vide better performances and a lower data acquisitiontime. For this new analyzer a “wide angle mode” lensoperation has been specifically designed for ARPESmeasurements reaching an angular acceptance within±13°. This mode guarantees a simultaneous and parallelacquisition over a wide angular range with a given an-gular resolution. With a 2D detection, an angular resolu-tion better than 0.1° can be achieved in the non energy-dispersive direction of the analyzer without restrictingthe acceptance angle. The reported ultimate energy reso-lution is 3 meV. For the “wide angle mode” and also the


27


Figure 3. (a) The photon flux through the beamline to end station measu-red with a photodiode using a pinhole of 6¥6 mm2 at 10 m from the ra-diation source, an entrance slit aperture of 300 µm, the indicated exit slit,and with 200 mA of electron current accumulated in the storage ring. (b)Fermi edge spectra (dots) of a molybdenum polycrystal at different tem-peratures. Their best fit (lines) give the total experimental energy resolu-tions including both the beamline and the SES 50 electron energy analy-zer contributions. Inset: Total experimental energy resolutions measuredat different pass energies of the SES 50 and with the sample at 30 K.

Figure 4. Image plot of the photoemission spectra of the Au(111) surfacestate dispersion. The white is the highest intensity.


28


“low angular dispersion” mode, the Phoibos 150 analyz-er can work at PE > KE. This means that, for instance, inthe “low angular dispersion” mode at KE = 2 eV it ispossible to work up to PE = 40 eV, while with the SES 50we must work up to PE = 2 eV. With the new electronanalyzer, therefore, we can expect an increase in the pho-toemission signal by a factor of about 20 and consideringthat the angular acceptance is 3–5 times bigger, the ac-quisition time of a normal band dispersion experimentmay be reduced by a factor 60–100. The Phoibos 150 ana-lyzer can also work in “transmission” mode, collectingone spectrum integrated over the angular acceptance.To conclude this presentation, some experimental resultsobtained with the SES 50 analyzer are briefly reported.Figure 4 shows the dispersion of the Au(111) surfacestate measured at room temperature (RT), with a photonenergy of 16 eV, and with an analyzer pass energy of5 eV. We can clearly resolve the spin-orbit split states [8]. In Figure 5 we show the Mg(0001) surface state disper-sion along the ΓK direction of the surface Brillouin zonemeasured at RT, with a photon energy of 9 eV, and withan analyzer pass energy of 2 eV. At this photon energy,apart the surface state dispersion (the most intenseband), it is also evident the bulk band dispersion at low-er kinetic energy [9,10]. This is due to the enhanced“bulk” sensitivity of photoemission at low photon ener-gy, as it is also confirmed by the photoemission lineshape near the Fermi level at about 5 eV of kinetic ener-gy (see Fig. 5c) [11].The authors wish to thank the ELETTRA staff for theirtechnical assistance, R. Claessen (University ofWuerzburg, Germany) for providing us the SES 50 spec-trometer, S. Gardonio and C. Carbone (ISM-CNR, Italy)for the Au(111) experiment. This project is supported bythe Italian Ministry of Education, University and Re-search (MIUR), under Contract FIRB No. RBAU01B5RS.

References1. S. Hufner, Photoelectron Spectroscopy, Springer-Verlag, Berlin, (1995).

2. F. Reinert, S. Hufner, New. J. Phys. 7 97 (2005).

3. A. Damascelli, Phys. Scr. T109 61 (2004).

4. T. Tanaka, H. Kitamura, Nucl. Instr. and Meth. in Phys. Res. A 364 368(1995).

5. B. Dviacco, Proc. Particle Accelerator Conference (2001).

6. T. Tanaka, H. Kitamura, J. Synchrotron Rad. 3 47 (1996).

7. L. Nahon et al., Rev. Sci. Instrum. 72 1320 (2001).

8. G. Nicolay et al., Phys. Rev. B 65 033407 (2001).

9. U. O. Karlsson et al., Phys. Rev. B 26 1852 (1982).

10. H. J. Gotsis et al., Phys. Rev. B 65 134101 (2002).

11. E. D. Hansen et al., Phys. Rev. B 55 1871 (1997).

Figure 5. (a) Photoemission spectra and (b) image plot of the Mg(0001)band dispersion along the ΓK direction. (c) Photoemission spectrum at Γpoint. The photon energy is 9 eV, the sample temperature is RT.

MUON & NEUTRON &SYNCHROTRON RADIATION NEWS

29


Following the regular 10-yearly safe-ty review of the its High Flux Reac-tor, - the so called Groupe Perma-nent – which took place in May 2002,the ILL started a wide-ranging set ofreinforcement and renewal of its nu-clear installations - the Refit Pro-gramme - one of whose aims beingcompliance with recent changes inseismic regulations.During the period 2002-2007 a hugeamount of work has been done, par-ticularly to withstand an earthquake: • Reinforcement of the building

housing the reactor • Establishment of operational and

command-control systems toshutdown the reactor in case ofearthquake

• New water circuit to feed the reac-tor tank and the canal which aretight in case of earthquake

• Removal of 1500 tons of buildingon the upper slab of the reactor.

• Cutting the front part of theguides halls and reinforcement ofthe office building

• New racks for spent fuel• Non destructive examination on

heavy water pipes welds. Itshowed no detected defect and noageing.

The REFIT is now practically com-pleted and the final review meetingtook place at the ILL on 11 Octoberthis year. The REFIT involved about10 people from ILL and 10 peoplefrom external companies and costedapproximately 30M€ including staff.Bravo to all those people who partic-ipated very actively and efficientlyto the ILL Refit Programme whichwill enable the ILL to operate safelyuntil 2030.

G. CicognaniCommunication and

Scientific SupportInstitut Laue-Langevin

News from ILLThe Refit Programme is completed!

Founded in 1967, the Institut Laue-Langevin (ILL) is an international re-search centre at the leading edge ofneutron science and technology. It isdirected by its Associates, thefounder countries, Germany, Franceand the United Kingdom, in associa-tion with its European ScientificMember countries. As a central facility, the ILL providesaccess to instruments that use low-energy neutrons of unequalled qual-ity and breadth to a community ofmany thousands of researchersthroughout Europe and beyond. TheILL has occupied this leading posi-tion for 35 years.In order to keep the ILL at the fore-front of neutron science and to pro-vide the best possible experimentalfacilities and support to its European

users over the next two decades, theInstitute needs to modernise its in-frastructure and instrument suite.This is the scope of the proposedILL20/20 upgrade programme,which can be summarised as follows:1. improving neutron moderators

and delivery systems;2. planning and prototyping new

instruments and neutron tech-nologies;

3. strengthening the links with theEuropean Synchrotron RadiationFacility (ESRF), creating partner-ships for science and joint scien-tific facilities accessible to ILL andESRF users;

4. developing the site shared by theILL, the European Molecular Biol-ogy Laboratory (EMBL) and theESRF to improve the visibility

and research capability of thiscommon site.

The ESFRI Project aims at optimisingthe preparatory phase of this ambi-tious programme. The preparationof the upgrade will involve: 1. feasibility studies on challenging

technical projects to renew theILL’s neutron moderators and de-livery systems, and on novel neu-tron scattering technologies andtechniques;

2. preparing the framework for aPartnership for Soft CondensedMatter;

3. planning the development of theILL/EMBL/ESRF site, includingthe resolution of the administra-tive issues.

R. WagnerDirector of the Institut Laue-Langevin

ILL 20/20The Upgrade Programme of the Institut Laue-Langevin


30


The deadline for proposal submission is

Tuesday, 4 March 2008, midnight (European time)

Proposal submission is only possible electronically.

Electronic Proposal Submission (EPS) is possible via our Visitors Club (http://club.ill.eu/cv/),once you have logged in with your personal username and password.

The detailed guide-lines for the submission of a proposal at the ILL can be found on the ILL web site:http://www.ill.eu/users/proposal-submission/.

The web system will be operational from 15 January 2008, and will be closed on 4 Marchat midnight (European time).

Please allow sufficient time for any unforeseen computing hitches.You will receive full support from the Visitors Club team. If you have any difficulties at all, please contactour web-support ([email protected]).

For any further queries, please contact the Scientific Co-ordination Office:ILL-SCO6 rue Jules HorowitzBP 156, F-38042 Grenoble Cedex 9phone: +33 4 76 20 70 82, fax: +33 4 76 48 39 06email: [email protected], http://www.ill.eu

Instruments availableThe following instruments will be available for the forthcoming round:

* Instruments marked with an asterisk are CRG instruments, where a smaller amount of beam time is available thanon ILL-funded instruments, but we encourage applications for these.

You will find details of the instruments on the web http://www.ill.fr/instruments-support/instruments-groups/

powder diffractometers: D1A, D1B*, D2B, D20, SALSA

liquids diffractometer: D4

polarised neutron diffractometers: D3, D23*

single-crystal diffractometers: D9, D10, D15*,VIVALDI

large scale structure diffractometers: D19, DB21, LADI

small-angle scattering: D11, D22

reflectometers:ADAM*, D17, FIGARO

small momentum-transfer diffractometer: D16

diffuse-scattering spectrometer: D7

three-axis spectrometers: IN1, IN8, IN12*, IN14,IN20, IN22*

time-of-flight spectrometers: IN4, IN5, IN6, BRISP*

backscattering and spin-echo spectrometers:IN10, IN11, IN13*, IN15, IN16

nuclear-physics instruments: PN1, PN3

fundamental-physics instruments: PF1B, PF2

Next ILL proposal round: call for proposals


31


Scheduling periodThose proposals accepted at the next round will be scheduled during the second two cycles in 2008.

Reactor Cycles for 2008 Cycle n° 150 (081) from 31/03/2008 to 20/05/2008

Cycle n° 151 (082) from 03/06/2008 to 23/07/2008

Cycle n° 152 (083) from 27/08/2008 to 16/10/2008

Cycle n° 153 (084) from 30/10/2008 to 19/12/2008

Start-ups and shut downs are planned at 8:30 am.

College SecretariesCollege 1 – Applied physics, instrumentation & techniques: Emanuel FarhiCollege 2 – Theory: Maxime CluselCollege 3 – Nuclear and Fundamental Physics: Ulli KoesterCollege 4 – Structural and Magnetic Excitations: Pascale DeenCollege 5A – Crystallography: Marie Helène Lemée-CailleauCollege 5B – Magnetism: Anne StunaultCollege 6 – Structure and Dynamics of Liquids and Glasses: Monica JimenezCollege 7 – Spectroscopy in solid state physics and chemistry: Stéphane RolsCollege 8 – Biology: Susana TeixeiraCollege 9 – Structure and Dynamics of Soft-condensed Matter: Peter Falus

Mandatory information for user’s reimbursementFollowing the implementation of new software for the reimbursement of travel and hotel expensesof ILL users and staff, we now need you to provide us with the following additional information:

Employer (Name,Address,Town, Country)

Type of contract you have with your employer(Permanent,Temporary, Student, PostDoc, Internship,Temporary Employment Agency)

When receiving an invitation to an experiment at the ILL, you will be asked to provide – by logging into the VisitorsClub and entering them in your profile - the necessary information if they are missing from your records. Please notethat this information is essential to be allowed to enter the site. It will be kept confidential and not used for anyother purposes.


32


International Symposium on PulsedNeutron and Muon Sciences (IPS 08)March 5-7, 2008 – Ibarakiken Shichouson Kaikan, Mito, Japan

The 1st J-PARC International Symposium

The J-PARC International Symposium onPulsed Neutron and Muon Sciences (IPS 08),

will focus on the high intensity pulsed spallation neutronand muon sources at MLF, in which the first user programwill begin in J-PARC. IPS08 will provide an opportunity tointroduce the performance of J-PARC and other facilities

in the world, and discuss prospective sciences andtechnologies performed in those facilities.

In order to fully respect the symposium scope,papers should concentrate on prospective aspects

in sciences and technologies.

Second Announcement

Organized byJ-PARC Center

Co-organized byInstitute of Materials Structure Science,High Energy Accelerator Research OrganizationQuantum Beam Science Directorate,Japan Atomic Energy Agency

Symposium ChairsYujiro Ikeda, JAEASusumu Ikeda, KEK

Contact Address: Hiroshi Takada, Kenji Nakajima - Materials and Life Science Division - J-PARC Center – Japan Atomic Energy AgencyTokai-mura, Naka-gun, Ibaraki-ken, 319-1195, Japan - Tel: +81 29 282 6936; Fax: +81 29 284 3889 - e-mail: [email protected]://www.ips08.com

At the meeting held in June, the ILLSteering Committee fully approvedand endorsed the priorities set out bythe ILL management for the instru-ment and infrastructure projects ofthe second phase (M-1 phase) of theMillennium Programme. The Chair-man of the Steering Committee, Prof.Michel Spiro, asked that it should bewidely communicated, especially tothe neutron community, that from atechnical viewpoint, the ILL reactorcan be operated safely beyond 2030.

This very important statement wasthen followed by the kick-off meet-ing of M-1 phase, which took placeon 10 July.With an investment budget of about52 M€ for the 2007-2013 period weare planning to:• build five new instruments:

ThALES, IN16B, D33, WASP and SuperADAM (the latter as a Swedish-German CRG instrument)

• upgrade four other instruments: IN1 Lagrange, IN4, D11, D17

• and phase out eight instruments: D1A, DB21, IN10, IN3, IN14, IN16, IN11 and ADAM

These plans also require the timelyre-siting of three instruments: D16,Cryo-EDM, LADI.

G. CicognaniCommunication and

Scientific SupportInstitut Laue-Langevin

Kick-off of the Second phaseof the ILL Millennium Programme

The High Flux Isotope Reactor(HFIR) at Oak Ridge National Labo-ratory (ORNL) resumed full poweroperations on May 16, 2007. Therewere three experiment cycles of 23 to25 days in FY2007 and another sixare proposed for FY2008 beginningin November 2007.During FY 2007, the High Flux Iso-tope Reactor delivered 1178 operat-ing hours to users. Commissioningof two SANS instruments is underway and these instruments will jointhe user program in 2008. The Neu-tron Scattering Science AdvisoryCommittee endorsed language en-couraging development of the sci-ence case for two instruments pro-posed for HFIR.Information about IMAGINE, a qua-si-Laue single crystal diffractometer,may be obtained from FloraMeilleur, [email protected] about the high resolu-tion cold neutron inelastic spectrom-eter may be obtained from YoungLee, [email protected]. Neutron production at the SNS be-gan on June 21, 2007, and endedSeptember 8, 2007. SNS resumedneutron production November 8,2007. The planned ramp-up to high-er power and increased reliability iswell ahead of schedule.On August 11, 2007, the SNS operat-ed at 183 kilowatts of routine beampower over 24 hours setting a powerrecord for a pulsed spallation neu-tron source. SNS cycle 2008-1 beganon November 5, 2007, and ends onFebruary 3, 2008.Neutron production is expected tobe 941 hours with an expected 80%beam delivery efficiency.Initially, the run power is 120 kWwith a planned ramp up to 340 kWduring the period. SNS delivered540 operating hours to users inFY2007.

The Wide Angular-Range ChopperSpectrometer (ARCS) team openedthe SNS beamline 18 shutter, send-ing the first neutrons to the instru-ment September 7, 2007.Commissioning of the instrumentwill continue into 2008. This is thefourth SNS instrument to receiveneutrons. Seven additional instru-ments will begin commissioning in2008, with the Spallation Neutronsand Pressure (SNAP) diffractometer,the Cold Neutron Chopper Spec-trometer (CNCS), the ExtendedQ-Range SANS (EQ-SANS), and thepowder diffractometer (POWGEN3)leading the others.A call for experimental proposals fornine instruments at the High FluxIsotope Reactor and Spallation Neu-tron Source was issued June 1, 2007,and closed on July 16, 2007, withover 200 proposals submitted. A sec-ond proposal call period is sched-uled for December 10, 2007 – Janu-ary 18, 2008. Significant leadership changes haveoccurred at ORNL during the lastyear. Dr. Thom Mason was namedthe director of Oak Ridge NationalLaboratory effective July 1, 2007. Dr.Ian Anderson succeeds Thom as As-sociate Laboratory Director for Neu-tron Sciences and Executive Directorof the Spallation Neutron Source.One of the six R&D 100 Awards re-ceived by Oak Ridge National Labo-ratory in 2007 was for the PharosNeutron Detector System. These topawards are given annually by R&DMagazine to the year’s most techno-logically significant new products.Pharos is a small low-power neutrondetection system that can be used toidentify nuclear materials at airportsand harbors and was developed byRichard Riedel of ORNL’s NeutronScattering Science Division, RonaldCooper of the Neutron Facilities De-

velopment Division, and LloydClonts of the Engineering Scienceand Technology Division.Neutron Scattering Science DivisionSenior Corporate Fellow HerbMook was among those to be re-cently elected a fellow of the Ameri-can Association for the Advance-ment of Science. He is cited for his“pioneering experiments using neu-tron scattering in materials that testtheories leading to understandingof novel physics and new directionsof research”. ORNL Users Week (October 8-11,2007) focused on the scientific re-sources of four ORNL user facilitiesfunded by the DOE Office of BasicEnergy Sciences: the Spallation Neu-tron Source, the High Flux IsotopeReactor, the Center for NanophaseMaterials Sciences, and the SharedResearch Equipment Program.Of the 78 institutions representedamong the 367 registrants, 55 werecolleges and universities.Talks and photos are located athttp://neutrons.ornl.gov/workshops/users2007/index.shtml.

A.E. EkkebusNeutron Scattering Science Division

Oak Ridge National Laboratory


33


News from SNSORNL neutron facilities deliver neutrons

SCIENTIFIC REVIEWS

34



European Conference on X-ray SpectrometryJune 16-20, 2008 – Cavtat, Dubrovnik, Croatia

Organized by Rud-er Boskovic Institute in co-operation with EXSA and IAEA

The thirteenth European Conference on Xray Spectrometry will be held in June 2008.Adriatic coast, picturesque Cavtat, magnificent and unique Dubrovnik will hostscientists of different backgrounds from Europe and worldwide in attempt to recognizeemerging and inventive xray spectrometry techniques as well as the important andsuccessful applications.

From experienced experts in the field, to young scientists searching for novelties andfinally industrial exhibitors with state of the art instruments, all participants will have achance to enjoy in rich scientific and social program of the forthcoming meeting, whichcomes after successful previous meetings in Alghero and Paris.

Main conference topics

• Interaction of X-rays with matter• X-ray sources, optics and detectors• Quantification methodology• WDXRS• TXRF and related techniques

• Synchrotron XRF• PIXE and electron induced XRS• Microbeam techniques• X-ray absorption (EXAFS, XANES)• X-ray imaging and tomography

• Applications:Materials and nanoscience,Life sciences, Cultural heritage,Earth and Environment sciences,Industrial applications

Second Announcement and Call for Papers

Important dates

March 1st, 2008 April 1st, 2008 May 1st, 2008 May 15th, 2008Submission of abstract Notification of acceptance Early Registration Final announcements

Contact AddressEXRS-2008 Secretariat, Rud-erBoskovic Institute, P.O. Box 18010002 Zagreb (Croatia)E-mail: [email protected]: http://exrs2008.irb.hr

SCHOOL AND MEETING REPORTS

35


The Italian Neutron School, organ-ised by the Italian Society of Neu-tron Spectroscopy (SISN) addressesto students, PhDs and young re-searchers aiming to approach theneutron spectroscopy by learning itsperformance and power in researchapplication.The 4th edition of the School –which took place this year – was fo-cused on the Inelastic Neutron Scat-tering in Liquids and DisorderedSystems.The school was composed of twoparts: a theoretical session was orga-nized in Sestri Levante (Genova,Italy) from 10 to 12 September, fol-lowed by an experimental sessionhosted by the ILL from 14 to 20 Sep-tember. During the theoretical ses-sion, together with an overview of

the principles of neutron spec-troscopy, a first approach to an idealexperiment and to the data reduc-tion was provided. The practical ses-sion was organised in cooperationwith the ILL, who hosted 20 Italianstudents providing not only logisticsupport but also access to instru-ments and computing facilities. Thestudents were shared between threedifferent instruments, the two ItalianCRGs, IN13 and BRISP, and the testtriple-axis instrument IN3. Thechoice of the latter was due to itshigh educational character.Real experiments were performedaddressing subjects such as: the in-fluence of the environment on pro-tein dynamics (IN13); phonons inlead and tantalum crystals (IN3); thestudy of Brillouin Scattering in com-

plex liquids (BRISP). Furthermore, ahigh educational experiment wasperformed on IN3, addressing thecomplex subject of the instrumentalresolution of a triple axis spectrome-ter. On performing the experiments,the students were able to practicethe beauties of neutron spectroscopy,which the theoretical session in Ses-tri Levante had previously encour-aged. The enthusiastic young experi-menters spent night and day bothmeasuring spectra on the instru-ments and making data analysis.The outcome of their thoughtfulwork was finally presented in a con-clusive seminar session.

F. Natali and A. OrecchiniILL

4th Italian Neutron Schoolof the Italian Society of Neutron Spectroscopy

Participants to the 4th Italian Neutron School.

CALL FOR PROPOSALS

36


Call for proposals forNeutron Sourceshttp://neutron.neutron-eu.net/n_about/n_where/europe

BNC Budapest Neutron CentreDeadlines for proposal submission:15th May (estended 31st May) and 30th October 2008www.bnc.hu/modules.php?name=News&file=article&sid=39

FRM-II Deadlines for proposal submission:25th January 2008https://user.frm2.tum.de/

GeNFGeesthacht Neutron FacilityDeadlines for proposal submission:Anytime during 2008www.gkss.de/index_e.html

ILLDeadlines for proposal submission:4th March 2008www.ill.fr/users/user-news/

ISISDeadlines for proposal submission:16th April and16th October 2008www.isis.rl.ac.uk/userOffice/

LLB-ORPHEE-SACLAYDeadlines for proposal submission:1st April and 1st October 2007www-llb.cea.fr/index_e.html

SINQSwiss Spallation Neutron SourceDeadlines for proposal submission:15th May 2008http://sinq.web.psi.ch/sinq/sinq_call.html

Call for proposals forSynchrotron Radiation Sourceswww.lightsources.org/cms/?pid=1000336#byfacility

ALSAdvanced Light SourceDeadlines for proposal submission:15th January and 15th March 2008www-als.lbl.gov/als/quickguide/independinvest.html

APSAdvanced Photon SourceDeadlines for proposal submission:7th March and 11th July 2008www.aps.anl.gov/Users/Scientific_Access/General_User/GUP_Calendar.htm

BESSYDeadlines for proposal submission:from 1st January to 15th February 2008www.bessy.de/boat/www/

BSRFBeijing Synchrotron Radiation FacilityDeadlines for proposal submission:Proposals are evaluated twice a yearwww.ihep.ac.cn/bsrf/english/userinfo/beamtime.htm

CFNCenter for Functional NanomaterialsDeadlines for proposal submission:31st January, 31st May and 30th September 2008www.bnl.gov/cfn/user/proposal.asp

CHESSCornell High Energy Synchrotron SourceDeadlines for proposal submission:30th April and 31st October 2008www.chess.cornell.edu/prposals/index.htm

CALL FOR PROPOSALS

37


CLSCanadian Light SourceDeadlines for proposal submission:31st March and 30th September 2008www.lightsource.ca/uso/call_proposals.php

ELETTRADeadlines for proposal submission:29th February and from 1st July to 31st December2008https://vuo.elettra.trieste.it/pls/vuo/guest.startup

ESRFEuropean Synchrotron Radiation FacilityDeadlines for proposal submission:15th January and 1st March 2008www.esrf.eu/UsersAndScience/UserGuide/Applying/

HASYLABHamburger Synchrotronstrahlungslabor at DESYDeadlines for proposal submission:1st March 2008http://hasylab.desy.de/user_info/write_a_proposal/2_deadlines/index_eng.html

NSLSNational Synchrotron Light SourceDeadlines for proposal submission:31st January 2008www.nsls.bnl.gov/

SLSSwiss Light SourceDeadlines for proposal submission:15th February, 15th March, 15th June, 15th Septemberand 15th October 2008http://sls.web.psi.ch/view.php/users/experiments/proposals/opencalls/index.html

SOLEILDeadlines for proposal submission:15th February and 15th September 2008http://www.synchrotron-soleil.fr/anglais/users/index.html

SPring-8Deadlines for proposal submission:22nd and 25th January, 4th and 7th February 2008www.spring8.or.jp/en/news/proposal/res_bl41_38_07b/announcements_view

SRCSynchrotron Radiation CenterDeadlines for proposal submission:1st February and August 2008www.src.wisc.edu/users/Forms/proposals.htm

SSRLStanford Synchrotron Radiation LaboratoryDeadlines for proposal submission:1st April, 1st May, 1st July, 1st November and 1stDecember 2008www-ssrl.slac.stanford.edu/users/user_admin/deadlines.html

CALENDAR

38


February 3-7, 2008 BIG SKY RESORT, USA

PXRMS 2008The 9th International Conference on the Physicsof X-Ray Multilayer Structureswww.rxollc.com/pxrms/

February 4-8, 2008 MELBOURNE, AUSTRALIA

AXAA 2008Australian X-ray Analytical Association Inc.(AXAA) Schools, Advanced Workshops, Conferenceand Exhibitionwww.pco.com.au/axaa2008/

February 5-7, 2008 GRENOBLE, FRANCE

ESRF Users’ Meeting 2008 & Associated Workshopshttp://www.esrf.eu/events/announcements/users-meeting-2008-associated-workshops

February 10-15, 2008 SAINTE LUCE, MARTINIQUE

ICDS 2008The Second International Conferenceon the Digital Society www.iaria.org/conferences2008/ICDS08.html

February 10-15, 2008 SAINTE LUCE, MARTINIQUE

ICQNM 2008The Second International Conferenceon Quantum, Nano, and Micro Technologies www.iaria.org/conferences2008/ICQNM08.html


1st ILL Annual School on Advanced NeutronDiffraction Data Treatment using the FullProf Suite ILLhttp://www.ill.eu/fpschool/

February 13-15, 2008 TOKYO, JAPAN

nano tech 2008International Nanotechnology Exhibition & Conferencewww.ics-inc.co.jp/nanotech/en/index.html

February 14-18, 2008 BOSTON, MA, USA

2008 AAAS Annual Meetingwww.aaas.org/meetings/Annual_Meeting/


Powder Diffraction with 2-Dimensional DetectorsPD2DDILLhttp://wwwold.ill.fr/dif/PD2DD/

March 3-7, 2008 BERLIN, GERMANY

29th Berlin School on Neutron Scattering Hahn-Meitner-Institut, Berlin, Germanywww.hmi.de/bensc/nschool2008/

March 5-8, 2008 MITO, JAPAN

The First J-PARC International SymposiumInternational Symposium on Pulsed Neutronand Muon Sciences (IPS 08) Ibarakiken Shichouson Kaikan, Mito, Japanwww.ips08.com/

March 10-14, 2008 NEW ORLEANS, LA, USA

American Physical Society Meetingwww.aps.org/meetings/march/index.cfm

March 24-28, 2008 SAN FRANCISCO, CA, USA

2008 MRS Spring Meetingwww.mrs.org/s_mrs/sec.asp?CID=6689&DID=174642

CALENDAR

39


April 3-4, 2008 TRIESTE, ITALY

Nanotechnologies applied to the aquatic environmentWorkshopwww2.ogs.trieste.it/nanotechnologies/

April 6-10, 2008 NEW ORLEANS, LA, USA

235th American Chemical Society National Meeting& Expositionwww.goingtomeet.com/conventions/details/10744

May 4-8, 2008 LAKE TAHOE, CA, USA

BIW082008 Beam Instrumentation Workshopwww-als.lbl.gov/biw08/

May 5-9, 2008 GRENOBLE, FRANCE

Application of Neutron and Synchrotron Radiatationto Magnetism ILLThe course is based on the 4th Hercules Short Course(HSC4) on Application of Neutron and SynchrotronRadiation to Magnetism, held between the 6th – 11thMay 2007

May 11-15, 2008 SANTA FE, NM, USA

ACNS 2008American Conference on Neutron Scattering http://lansce.lanl.gov/ACNS2008/index.html


Surfaces and Interfaces in Soft Matter and Biology -the impact and future of neutron reflectivity ILLwww.ill.fr/fileadmin/users_files/Other_Sites/events/rktsymposium/index.html

May 26-29, 2008 VILLARD DE LANS, FRANCE

5th International workshop on Sample Environmentat Neutron Scattering FacilitiesHôtel de Paris, 124 Place Pierre Chabert, 38250,Villard de Lans

May 28 - June 1, 2008 AMSTERDAM,THE NETHERLANDS

WBC 20088th World Biomaterials Congress www.wbc2008.com/


International workshop on particle physicswith slow neutrons ILLwww.ill.eu/fileadmin/users_files/documents/instruments_and_support/instruments_and_groups/NPP/npp_workshop2008/start.html

June 7-14, 2008 BOMBANNES, GIRONDE, FRANCE

9th European Summer School on Scattering Methodsapplied to Soft Condensed Matter www.ill.eu/news-events/workshops-events/bombannes/

June 9-10, 2008 SASKATOON, CANADA

Canadian Light Source 11th Annual Users’ Meetingwww.lightsource.ca/uac/meeting2008/index.php

June 9-12, 2008 CHONGQING, P.R. CHINA

2008 MRS International Materials Research Conferencewww.mrs.org/s_mrs/sec.asp?CID=7060&DID=178708

June 10-13, 2008 SASKATOON, CANADA

MEDSI/Pan-American SRI 2008 Meetingwww.lightsource.ca/medsi-sri2008/index.php

CALENDAR

40


June 15-20, 2008 AMELIOWKA, POLAND

ISSRNS 20089th International School and Symposiumon Synchrotron Radiation in Natural Science www.synchrotron.org.pl/ISSRNS2008/

June 16-20, 2008 CAVTAT, DUBROVINIK, CROATIA

European Conference on X-Ray Spectrometryhttp://exrs2008.irb.hr/

June 23-27, 2008 GENOA, ITALY

EPAC0811th European Particle Accelerator Conferencewww.epac08.org/

June 25-27, 2008 SWEDEN AND DENMARK

PCST-10Malmö, Lund and Copenhagen, Sweden and Denmarkwww.vr.se/pcst

July 20-23, 2008 CAMPINAS, BRAZIL

SRMS-66th International Conference on Synchrotron Radiationin Materials Sciencewww.srms-6.com.br/

July 21-25, 2008 ZURICH, SWITZERLAND

XRM 20089th International Conference on X-Ray Microscopy http://xrm2008.web.psi.ch/

July 28 - August 1, 2008 SYDNEY, AUSTRALIA

IUMRS-ICEM 2008International Conference on Electronic Materials -Symposium J: Synchrotron Radiationwww.aumrs.com.au/ICEM-08/Symposia/?S=9

FACILITIES

41


BNC - Budapest Research reactorBudapest Research Centre, HungaryType: Swimming pool reactor, 10MWEmail: [email protected] www.bnc.hu

BENSC - Berlin Neutron Scattering CenterHahn-Meitner-InstitutGlienicker Strasse 100D-14109 Berlin, GermanyPhone: +49/30/8062 2778Fax: +49/30/8062 2523E-mail: [email protected]/bensc/index_en.html

CNFCanadian Neutron Beam CentreNational Research Council of CanadaBuilding 459, Station 18Chalk River Laboratories, Chalk River, OntarioCanada K0J 1J0Phone: 1 (888) 243 2634 (toll free) / 1 (613) 584 8811ext. 3973; Fax: 1 (613) 584 4040http://cnf-ccn.gc.ca/home.html

FLNP - Frank Laboratory of Neutron PhysicsGpulsed reactor, mean 2 MW, pulse 1500 MWJoint Institute for Nuclear ResearchDubna, RussiaE-mail: [email protected]

FRG-1 Geesthacht (D)Type: Swimming Pool Cold Neutron SourceFlux: 8.7 x 1013 n/cm2/sAddress for application forms and informations:Reinhard Kampmann, Institute for Materials Science,Div. Wfn-Neutronscattering, GKSS, Research Centre,21502 Geesthacht, GermanyPhone: +49 (0)4152 87 1316/2503;Fax: +49 (0)4152 87 1338E-mail: [email protected]

FRJ-2 Forschungszentrum Jülich GmbHType: DIDO (heavy water), 23 MWResearch Centre Jülich, D-52425, Jülich, GermanyE-mail: [email protected]/iff/wns/

FRM, FRM-2 (D)Technische Universität MünchenType: Compact 20 MW reactorFlux: 8 x 1014 n/cm2/sAddress for information:Prof. Winfried Petry,FRM-II Lichtenbergstrasse 1 - 85747 GarchingPhone: 089 289 14701Fax: 089 289 14666E-mail: [email protected]/en/index.html

HFIRORNL, Oak Ridge, USAPhone: (865) 574 5231; Fax: (865) 576 7747E-mail: [email protected]://neutrons.ornl.gov/

HIFARANSTO, AustraliaNew Illawarra Road, Lucas Heights NSW, AustraliaPhone: 61 2 9717 3111E-mail: [email protected]/information_about/our_facilities.html

ILL Grenoble (F)Type: 58MW High Flux ReactorFlux: 1.5 x 1015 n/cm2/sScientific Coordinator: Dr. G. CicognaniILL, BP 156, 38042 Grenoble Cedex 9, FrancePhone: +33 4 7620 7179Fax: +33 4 76483906E-mail: [email protected] and [email protected]

N E U T R O N S O U R C E SNEUTRON SCATTERING WWW SERVERS IN THE WORLD(http://idb.neutron-eu.net/facilities.php)

FACILITIES

42


IPNS - Intense Pulsed Neutron at Argonne (USA)For proposal submission by e-mail send [email protected] or mail/fax to:IPNS Scientific Secretary, Building 360Argonne National Laboratory, 9700 South Cass Avenue,Argonne, IL 60439-4814, USAPhone: 630/252 7820; Fax: 630/252 7722 www.pns.anl.gov

ISIS DidcotType: Pulsed Spallation SourceFlux: 2.5 x 1016n fast/sAddress for application forms:ISIS Users Liaison Office, Building R3,Rutherford Appleton Laboratory, Chilton,Didcot, Oxon OX11 0QXPhone: +44 (0) 1235 445592Fax: +44 (0) 1235 445103E-mail: [email protected]

JRR-3MTokai-mura, Naka-gun,Ibaraki-ken 319-11, Japan.Jun-ichi Suzuki,JAERI - Japan Atomic Energy Research InstituteYuji Ito (ISSP, Univ. of Tokyo)Fax: +81 292 82 59227; Telex: JAERIJ24596E-mail: [email protected]://ciscpyon.tokai-sc.jaea.go.jp/english/index.cgi

JEEP-II Reactor KjellerType: D2O moderated 3.5% enriched UO2 fuel.Flux: 2 x 1013 n/cm2/sAddress for application forms:Institutt for EnergiteknikkK.H. Bendiksen, Managing DirectorBox 40, 2007 Kjeller, NorwayPhone: +47 63 806000 - 806275Fax: +47 63 816356E-mail: [email protected]

KENS Institute of Materials Structure ScienceHigh Energy Accelerator research Organisation1-1 Oho, Tsukuba-shi, Ibaraki-ken, 305-0801, JapanE-mail: [email protected]://neutron-www.kek.jp/index_e.html

KUR - Kyoto University Research Reactor InstituteKumatori-cho Sennan-gun,Osaka 590-0494,JapanPhone:+81 72 451 2300; Fax:+81 72 451 2600www.rri.kyoto-u.ac.jp/en/

LANSCE - Los Alamos Neutron Science CenterTA-53, Building 1, MS H831Los Alamos National Lab, Los Alamos, USAPhone: +1 505 665 8122E-mail: [email protected]/index.html

LLB Orphée Saclay (F)Type: Reactor.Flux: 3.0 x 1014 n/cm2/sLaboratoire Léon Brillouin (CEA-CNRS)E-mail: [email protected]/index_e.html

NFL – Studsvick Neutron Research LaboratoryUppsala UniversityStudsvik Nuclear AB, Stockholm, SwedenType: swimming pool type reactor, 50 MW,with additional reactor 1 MWhttp://idb.neutron-eu.net/facilities.php

NCNR - NIST Center for Neutron ResearchNational Institute of Standards and Technology100 Bureau Drive, MS 8560Gaithersburg, MD 20899-8560, USAPatrick Gallagher, DirectorPhone: (301) 975 6210Fax: (301) 869 4770E-email: [email protected]://rrdjazz.nist.gov

NPL – NRIType: 10 MW research reactorAddress for informations:Zdenek Kriz, Scientific SecretaryNuclear Research Institute Rez plc, 250 68 Rez - Czech RepublicPhone: +420 2 20941177 / 66173428Fax: +420 2 20941155E-mail: [email protected] and [email protected]

FACILITIES

43


NRU Chalk River LaboratoriesThe peak thermal flux 3x1014 cm-2 sec-1

Neutron Program for Materials Research National Research Council Canada Building 459, Station 18 Chalk River Laboratories Chalk River, Ontario - Canada K0J 1J0Phone: 1 (888) 243 2634 (toll free)Phone: 1 (613) 584 8811 ext. 3973;Fax: 1 (613) 584 4040http://neutron.nrc-cnrc.gc.ca/home.html

RID Reactor Institute Delft (NL)Type: 2MW light water swimming poolFlux: 1.5 x 1013 n/cm2/sAddress for application forms:Dr. M. Blaauw, Head of Facilities and Services Dept.Reactor Institute Delft, Faculty of Applied SciencesDelft University of Technology, Mekelweg 152629 JB Delft, The NetherlandsPhone: +31 15 2783528; Fax: +31 15 2788303E-mail: [email protected]

SINQ Villigen (CH)Type: Steady spallation sourceFlux: 2.0 x 1014 n/cm2/sContact address: PSI-Paul Scherrer InstitutUser Office, CH-5232 Villigen PSI, SwitzerlandPhone: +41 56 310 4666; Fax: +41 56 310 3294E-mail: [email protected]://sinq.web.psi.ch

SNS - Spallation Neutron SourceORNL, Oak Ridge, USAAddress for information:Allen E. EkkebusSpallation Neutron Source,Oak Ridge National LaboratoryOne Bethel Valley Road, Bldg 8600P.O. Box 2008, MS 6460Oak Ridge, TN 37831-6460Phone: (865) 241 5644Fax: (865) 241 5177E-mail: [email protected]

FACILITIES

44


ALBA – Synchrotron Light FacilityCELLS - ALBA Edifici Ciències. C-3 central.Campus UABCampus Universitari de Bellaterra.Universitat Autònoma de Barcelona08193 Bellaterra, Barcelona – SpainPhone: +34 93 592 43 00Fax: +34 93 592 43 01 www.cells.es

ALS - Advanced Light SourceBerkeley Lab, 1 Cyclotron Rd, MS6R2100,Berkeley, CA 94720Phone: +1 510 486 7745Fax: +1 510 486 4773E-mail: [email protected]/als/

ANKAForschungszentrum Karlsruhe Institutfür SynchrotronstrahlungHermann-von-Helmholtz-Platz 1,76344 Eggenstein-Leopoldshafen, GermanyPhone: +49 (0)7247 82 6071Fax: +49-(0)7247 82 6172E-mail: [email protected]://ankaweb.fzk.de/

APS - Advanced Photon SourceArgonne Nat. Lab. 9700 S. Cass Avenue,Argonne, Il 60439, USAPhone: (630) 252 2000, Fax: +1 708 252 3222E-mail: [email protected]

AS - Australian SynchrotronLevel 17, 80 Collins St., Melbourne, VIC 3000, AustraliaPhone: +61 3 9655 3315Fax: +61 3 9655 8666E-mail: [email protected]/content.asp?Document_ID=1

BESSY - Berliner Elektronenspeicherring Gessellschaft. fürSynchrotronstrahlungBESSY GmbH, Albert Einstein Str.15,12489 Berlin, GermanyPhone: +49 (0)30 6392 2999Fax: +49 (0)30 6392 2990E-mail: [email protected]

BSRF - Beijing Synchrotron Radiation FacilityBEPC National LaboratoryInstitute of High Energy PhysicsChinese Academy of SciencesP.O. Box 918 Beijing 100039 – P.R. ChinaPhone: +86-10-68235125Fax: +86-10-68222013E-mail: [email protected]/bsrf/english/main/main.htm

CAMD - Center Advanced Microstructures & DevicesCAMD/LSU 6980 Jefferson Hwy. – Baton Rouge,L.A. 70806 USAPhone: +1 (225) 578 8887Fax : +1 (225) 578 6954E-mail: [email protected]

CANDLE - Center for the Advancement of Natural Discoveriesusing Light EmissionAcharyan 31 375040, Yerevan, ArmeniaPhone/Fax: +374 1 629806E-mail: [email protected]/index.html

CFN - Center for Functional NanomaterialsUser Administration Office Brookhaven National Laboratory P.O. Box 5000, Bldg. 555 Upton, NY 11973-5000, USAPhone: +1 (631) 344 6266 Fax: +1 (631) 344 3093E-mail: [email protected]/cfn/

CHESS - Cornell High Energy Synchrotron SourceCornell High Energy Synchrotron Source200L Wilson Lab, Rt. 366 & Pine Tree RoadIthaca, NY 14853 – USAPhone: +1 (607) 255 7163 , +1 (607) 255 9001www.chess.cornell.edu

CLIO - Centre Laser Infrarouge d’OrsayCLIO/LCPBat. 201 - P2 Campus Universitaire 91405 ORSAY Cedex, Francewww.lcp.u-psud.fr/clio/clio_eng/clio_eng.htm

S Y N C H R OT R O N R A D I AT I O N S O U R C E SSYNCHROTRON SOURCES WWW SERVERS IN THE WORLD(http://www.lightsources.org/cms/?pid=1000098)

FACILITIES

45


CLS - Canadian Light SourceCanadian Light Source Inc.University of Saskatchewan101 Perimeter Road Saskatoon, SK. Canada. S7N 0X4Phone: (306) 657 3500; Fax: (306) 657 3535E-mail: [email protected]

CNM - Center for Nanoscale MaterialsArgonne National Laboratory 9700 S. Cass Avenue. Bldg. 440 Argonne, IL 60439, USAPhone: (630) 252 2000http://nano.anl.gov/facilities/index.html

CTST - UCSB Center for Terahertz Science and TechnologyUniversity of California, Santa Barbara (UCSB), USAhttp://sbfel3.ucsb.edu/

DAFNE LightINFN – LNFVia Enrico Fermi, 40, I-00044 Frascati (Rome), Italyfax: +39 6 94032597www.lnf.infn.it/esperimenti/sr_dafne_light/

DELSY - Dubna ELectron SYnchrotronJINR Joliot-Curie 6, 141980 Dubna,Moscow region, RussiaPhone: + 7 09621 65 059Fax: + 7 09621 65 891E-mail: [email protected] www.jinr.ru/delsy/

DELTA - Dortmund Electron Test AcceleratorFELICITA I (FEL)Institut für Beschleunigerphysik undSynchrotronstrahlung, Universität DortmundMaria-Goeppert-Mayer-Str. 2,44221 Dortmund, GermanyFax: +49 (0)231 755 5383http://www.delta.uni-dortmund.de/index.php?id=2&L=1

DFELL - Duke Free Electron Laser LaboratoryDuke Free Electron Laser Laboratory P.O. Box 90319 Duke University Durham,North Carolina 27708-0319 USAPhone: 1 (919) 660 2666; Fax: +1 (919) 660 2671E-mail: [email protected]

Diamond Light SourceDiamond Light Source LtdDiamond House, Chilton, Didcot OXON OX11 0DE UKPhone: +44 (0)1235 778000; Fax: +44 (0)1235 778499E-mail: [email protected]://www.diamond.ac.uk/default.htm

ELETTRA Synchrotron Light Lab.Sincrotrone Trieste S.C.p.AStrada Statale 14 - Km 163,5 in AREA Science Park,34012 Basovizza, Trieste, ItalyPhone: +39 40 37581Fax: +39 (040) 938 0902www.elettra.trieste.it

ELSA - Electron Stretcher AcceleratorPhysikalisches Institut der Universität BonnBeschleunigeranlage ELSA, Nußallee 12,D-53115 Bonn, GermanyPhone: +49 228 735926Fax +49 228 733620 E-mail: [email protected]/elsa-facility_en.html

ESRF - European Synchrotron Radiation Lab.ESRF, 6 Rue Jules Horowitz, BP 220,38043 Grenoble Cedex 9 FRANCEPhone: +33 (0)4 7688 2000Fax: +33 (0)4 7688 2020E-mail: [email protected]

FELBE - Free-Electron Lasers at the ELBE radiation sourceat the FZR/DresdenBautzner Landstrasse 128 – 01328 Dresden, Germanywww.fzd.de/db/Cms?pNid=471

FELIX - Free Electron Laser for Infrared eXperimentsFOM Institute for Plasma Physics 'Rijnhuizen'Edisonbaan, 14 3439 MN Nieuwegein, The NetherlandsP.O. Box 1207, 3430 BE Nieuwegein, The NetherlandsPhone: +31 30 6096999Fax: +31 30 6031204E-mail: [email protected]/felix/

HASYLAB - Hamburger SynchrotronstrahlungslaborDORIS III, PETRA II / III, FLASHDESY - HASYLAB Notkestrasse 85, 22607 Hamburg, GermanyPhone: +49 40/8998 2304Fax: +49 40/8998 2020E-mail: [email protected]://hasylab.desy.de/

HSRC Hiroshima Synchrotron Radiation Center - HiSOR Hiroshima University2-313 Kagamiyama, Higashi-Hiroshima,739-8526 JapanPhone: +81 82 424 6293Fax: +81 82 424 6294www.hsrc.hiroshima-u.ac.jp/index.html

FACILITIES

46


iFELInstitute of Free Electron Laser,Graduate School of Engineering, Osaka University2-9-5 Tsuda-Yamate, Hirakata, Osaka 573-0128 JapanPhone: +81 (0)72 897 6410www.fel.eng.osaka-u.ac.jp/english/index_e.html

INDUS -1 / INDUS -2 Centre for Advanced Technology Departmentof Atomic Energy Government of IndiaP.O.: CAT Indore M.P. - 452 013 India Phone: +91 731 248 8003Fax: 91 731 248 8000E-mail: [email protected] www.cat.ernet.in/technology/accel/indus/index.htmlwww.cat.ernet.in/technology/accel/atdhome.html

IR FEL Research Center – FEL-SUTIR FEL Research CenterResearch Institutes for Science and TechnologyThe Tokyo University of Science, Yamazaki 2641, Noda,Chiba 278-8510, JapanPhone: +81 4 7121 4290Fax: +81 4 7121 4298E-mail: [email protected]/~felsut/english/index.htm

ISA - Institute for Storage Ring Facilities – ASTRID-1ISA, University of Aarhus, Ny Munkegade,bygn. 520, DK-8000 Aarhus C, DenmarkPhone: +45 8942 3778Fax: +45 8612 0740E-mail: [email protected]

ISI-800Institute of Metal PhysicsNational Academy of Sciences of UkrainePhone: +(380) 44 424 1005Fax: +(380) 44 424 2561E-mail: [email protected]

Jlab - Jefferson Lab FEL12000 Jefferson Avenue, Newport News,Virginia 23606 USAPhone: (757) 269 7767www.jlab.org/FEL

Kharkov Institute of Physics and TechnologyPulse Stretcher/Synchrotron RadiationNational Science Center, KIPT, 1Akademicheskaya St., Kharkov, 61108 UkrainePhone: 38 (057) 335 35 30Fax: 38 (057) 335 16 88http://www.kipt.kharkov.ua/.indexe.html

KSR Nuclear Science Research FacilityAccelerator LaboratoryGokasho,Uji, Kyoto 611Fax: +81 774 38 3289wwwal.kuicr.kyoto-u.ac.jp/www/index-e.htmlx

KSRS - Kurchatov Synchrotron Radiation SourceKSRS - Siberia-1 / Siberia-2Kurtchatov Institute 1Kurtchatov Sq., Moscow 123182, Russia http://www.kiae.ru/

LCLS - Linac Coherent Light SourceStanford Linear Accelerator Center (SLAC)2575 Sand Hill Road, MS 18, Menlo ParkCA 94025 USAPhone: +1 (650) 926 3191Fax: +1 (650) 926 3600E-mail: [email protected] www-ssrl.slac.stanford.edu/lcls/

LNLS - Laboratorio Nacional de Luz SincrotronCaixa Postal 6192, CEP 13084-971Campinas, SP, BrazilPhone: +55 (0) 19 3512 1010Fax: +55 (0)19 3512 1004E-mail: [email protected]/index.asp?idioma=2&opcaoesq

MAX-LabBox 118, University of Lund, S-22100 Lund, SwedenPhone: +46 222 9872; Fax: +46 222 4710www.maxlab.lu.se/

Medical Synchrotron Radiation FacilityNational Institute of Radiological Sciences (NIRS)4-9-1, Anagawa, Inage-ku, Chiba-shi, 263-8555, JapanPhone: +81 (0)43 251 2111http://www.nirs.go.jp/ENG/index.html

MLS - Metrology Light SourcePhysikalisch-Technische BundesanstaltWilly-Wien-LaboratoriumMagnusstraße 9, 12489 Berlin, GermanyPhone: +49 30 3481 7312; Fax: +49 30 3481 7550E-mail: [email protected]/mls/

NSLS - National Synchrotron Light SourceNSLS User Administration OfficeBrookhaven National Laboratory,P.O. Box 5000, Bldg. 725B Upton, NY 11973-5000 USAPhone: +1 (631) 344 7976; Fax: +1 (631) 344 7206 E-mail: [email protected] www.nsls.bnl.gov

FACILITIES

47


NSRL - National Synchrotron Radiation Lab.University od Science and Technology China (USTC)Hefei, Anhui 230029, P.R. ChinaPhone: +86 551 5132231, 3602034 Fax: +86 551 5141078E-mail: [email protected]/en/

NSRRC - National Synchrotron Radiation Research CenterNational Synchrotron Radiation Research Center 101 Hsin-Ann Road, Hsinchu Science Park,Hsinchu 30076, Taiwan, R.O.C.Phone: +886 3 578 0281Fax: +886 3 578 9816E-mail: [email protected]

NSSR - Nagoya University Small Synchrotron Radiation FacilityNagoya University4-9-1,Anagawa, Inage-ku, Chiba-shi, 263-8555 JapanPhone: +81 (0)43 251 2111www.nagoya-u.ac.jp/en/

PAL - Pohang Accelerator Lab.San-31 Hyoja-dong Pohang,Kyungbuk 790-784, Koreahttp://pal.postech.ac.kr/eng/index.html

PF - Photon FactoryKEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, JapanPhone: +81 (0) 29 879 6009; Fax: +81 (0) 29 864 4402E-mail: [email protected]://pfwww.kek.jp/

PSLS - Polish Synchrotron Light SourceCentrum Promieniowania SynchrotronowegoSp. z o.o.ul. Reymonta 4, PL - 30-059 KrakówPhone: +48 (12) 663 58 20E-mail: [email protected]/Synchro/

RitS Ritsumeikan University SR CenterRitsumeikan University (RitS) SR CenterBiwako-Kusatsu Campus,Noji Higashi 1-chome, 1-1 Kusatsu,525-8577 Shiga-ken, JapanPhone: +81 (0)77 561 2806Fax: +81 (0)77 561 2859E-mail: [email protected]/se/re/SLLS/newpage13.htm

SAGA-LS - Saga Light SourceKyushu Synchrotron Light Research Center8-7 Yayoigaoka, Tosu, Saga 841-0005, Japan Phone: +81 942 83 5017; Fax: +81 942 83 5196www.saga-ls.jp/english/index.htm

SESAME Synchrotron-light for Experimental Scienceand Applications in the Middle EastE-mail: [email protected]/index.aspx

SLS - Swiss Light SourcePaul Scherrer Institut reception building,PSI West, CH-5232 Villigen PSI, SwitzerlandPhone: +41 56 310 4666; Fax: +41 56 310 3294E-mail: [email protected]://sls.web.psi.ch/view.php/about/index.html

SOLEILSynchrotron SOLEILL'Orme des Merisiers Saint-Aubin - BP 48 91192 Gif-sur-Yvette Cedex, FrancePhone: +33 1 6935 9652; Fax: +33 1 6935 9456E-mail: [email protected]://www.synchrotron-soleil.fr/

SPL - Siam Photon LaboratoryThe Siam Photon Laboratoryof the National Synchrotron Research Center111 University Avenue, Muang District,Nakhon Ratchasima 30000, ThailandPO. Box 93, Nakhon Ratchasima 30000, Thailand Phone: +66 44 21 7040Fax: +66 44 21 7047, +66 44 21 7040, ext. 211www.nsrc.or.th/eng/

SPring-8Japan Synchrotron Radiation Research Institute (JASRI)Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, JapanPhone: +81 (0) 791 58 0961Fax: +81 (0) 791 58 0965E-mail: [email protected]/en/

SRC - Synchrotron Radiation CenterSynchrotron Radiation Center3731 Schneider Dr., Stoughton,WI 53589-3097, USAPhone: +1 (608) 877 2000Fax: +1 (608) 877 2001www.src.wisc.edu

SRS - Synchrotron Radiation SourceCCLRC Daresbury Laboratory,Warrington, Cheshire, UK WA4 4ADPhone: +44 (0)1925 603223Fax: +44 (0)1925 603174E-mail: [email protected]/srs/

FACILITIES

48


SSLS Singapore Synchrotron Light Source – Helios IINational University of Singapore (NUS)Singapore Synchrotron Light Source,National University of Singapore5 Research Link, Singapore 117603, SingaporePhone: (65) 6874 6568; Fax: (65) 6773 6734http://ssls.nus.edu.sg/index.html

SSRC Siberian Synchrotron Research CentreVEPP3/VEPP4Lavrentyev av. 11, Budker INP,Novosibirsk 630090, RussiaPhone: +7 (3832) 39 44 98; Fax: +7 (3832) 34 21 63E-mail: [email protected]://ssrc.inp.nsk.su/english/load.pl?right=general.html

SSRF - Shanghai Synchrotron Radiationhttp://ssrf.sinap.ac.cn/english/

SSRL - Stanford Synchrotron Radiation Lab.Stanford Linear Accelerator Center,2575 Sand Hill Road, Menlo Park,CA 94025, USAPhone: +1 650 926 4000; Fax: +1 650 926 3600E-mail: [email protected]/users/user_admin/ura_staff_new.html

SRS - Synchrotron Radiation SourceCCLRC Daresbury Lab.Warrington, Cheshire, WA4 4AD, U.K.Phone: +44 (0)1925 603223Fax: +44 (0)1925 603174E-mail: [email protected]/srs/

SuperSOR Synchrotron Radiation FacilitySynchrotron Radiation LaboratoryInstitute for Solid State Physics,University of Tokyo5-1-5 Kashiwa-no-ha, Kashiwa,Chiba 277-8581, JapanPhone: +81 (0471) 36 3405; Fax: +81(0471) 34 6041E-mail: [email protected]/labs/sor/project/MENU.html

SURF-II / SURF-III - Synchrotron Ultraviolet Radiation FacilityNIST, 100 Bureau Drive, Stop 3460, Gaithersburg,MD 20899-3460 USAPhone: +1 301 975 6478http://physics.nist.gov/MajResFac/SURF/SURF/index.html

TNK _ F.V. Lukin InstituteState Research Center of Russian Federation103460, Moscow, ZelenogradPhone: +7(095) 531 1306 / +7(095) 531 1603Fax: +7(095) 531 4656E-mail: [email protected]://www.niifp.ru/index_e.html

TSRF - Tohoku Synchrotron Radiation FacilityLaboratory of Nuclear ScienceTohoku UniversityPhone: +81 (022) 743 3400; Fax: +81 (022) 743 3401E-mail: [email protected]/index.php

UVSOR - Ultraviolet Synchrotron Orbital Radiation FacilityUVSOR Facility, Institute for Molecular Science,Myodaiji, Okazaki 444-8585, Japanwww.uvsor.ims.ac.jp/defaultE.html

VU FEL – W. M. Keck Vanderbilt Free-electron Laser Center410 24th Avenue Nashville, TN 37212, Box 1816, Stn B,Nashville, TN 37235 USAwww.vanderbilt.edu/fel/

Documents

NN Vol13 n1 DEF - Istituto Nazionale di Fisica Nuclearestatistics.roma2.infn.it/~notiziario/2008/pdf/vol13-n1_08.pdf · grammes at Risø starting in FP3 in 1991. By 1993 five other