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This article was downloaded by: [University of Tennessee, Knoxville]On: 19 December 2014, At: 13:57Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK
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26Th ssrl users conferenceAudrey Archuleta aa SSRLPublished online: 06 May 2008.
To cite this article: Audrey Archuleta (2000) 26Th ssrl users conference, Synchrotron Radiation News, 13:2, 2-5, DOI:10.1080/08940880008261061
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26fh SSRL Users Conference
More than 190 attendees repre- senting over 3 5 universities and re- search institutions gathered for the 26‘h Annual Stanford Synchrotron Radiation Laboratory Users’ Confer- ence, October 11-12, 1999. T h e Us- ers’ Conference started off a week of activities including two workshops, the 1999 National Synchrotron Ra- diation Instrumentation (SRI99) Con- ference (October 13-15), and a Linac Coherent Light Source (LCLS) Work- s h o p (Oc tobe r 15-16). An ar t ic le detail ing SRI99 can be found on page 5 . T h e Users’ Conference w a s organized by the SSRL Users’ Or- ganizat ion Executive Commi t t ee , together with conference cha i r s Jo Stohr , IBM Almaden Research Cen- ter, a n d Bruce Clemens, S t an fo rd University.
Thirteen scientific talks were pre- sented in four sessions-Current and Future Science, Mater ia ls Science, Environmental Science and Structural Molecular Biology. A special session dedicated to SSRL Facility Reports included a status report on SPEAR3. SPEAR3 is the recently started up-
grade that will bring to the SSRL storage ring third-generation charac- teristics including 18 nm-radian (or lower) beam emittance, a decrease from 160 nm-rad; 500 mA stored beam current, a factor of five in- crease; 3 GeV “ a t energy” injec- t ion, a n increase from the c u r r e n t 2 .3 GeV; a n d the capabili ty to main- ta in long beam lifetimes (>25 hour s a t 200 mA.) T h e ma jo r po r t ion of this installation is current ly planned fo r a n approx ima te ly s ix -mon th s h u t d o w n in 2002.
I n c o m i n g ( S e p t e m b e r 1 9 9 9 ) Stanford Linear Accelerator Center (SLAC) Director Jonathan Dorfan opened the conference with an eye towards the new opportunities a t SSRL and the planned upgrades that will affecr users far into the future. SSRL Director Keith Hodgson’s re- port highlighted user and experimen- tal trends a t the facility. Among these are new technical staff to augment user support , a new 12-Tesla high- magnetic-field materials scattering and spectroscopy facility, a hutch reconfiguration for beam line 7-3,
Second Anniinl Lytle Award recipient, Tom Hostetler (right), receives a plaque, a chainsaw (to help cut through “red tape”), and a handshake from the Award’s namesnke, Fnrrel Lytle (left).
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and a new 30-element Ge detector available early in 2000.
Hodgson also discussed the strong growth trend in molecular environ- mental sciences and the status of a new dedicated beam line for X-ray absorption spectroscopy in this area (beam line 11-2) that will continue commissioning during the run that began in November 1999. This beam line features a new mono- chromator design with liquid ni- trogen cooling and a radioactive materials storage room adjacent to the beam line hutch.
A fifth macromolecular crystallog- raphy beam line is being added as a side station on beam line 11 (beam line 11-1), a joint effort between The Scripps Research Institute, Stanford University and SSRL. Additional funding from the National Institutes of Health’s General Medicine Insti- tute (NIGMS) will be used for gen- eral user support and development on this and other macromolecular crystallography beam lines a t SSRL. Other highlights included a new LIGA branchline and the future extension of the beam line 4-2 hutch to mini- mize changeover time between small angle X-ray scattering and X-ray ab- sorption spectroscopy experiments. General user statistics and trends were also discussed and Hodgson’s talk concluded with an emphasis on the importance of safety and environ- mental protection as a fundamental part of how staff and users conduct business a t SSRL.
The Department of Energy’s Office of Basic Energy Sciences Deputy Asso- ciate Director, Iran Thomas, spoke on the two guidelines directing the Office of Science: family and safety. After a brief discussion on the cur re2 budget outlook, Thomas gave anecdotes of the early days of protein crystallogra- phy and marveled at the changes that have taken place over the last 10-15 years, yielding recent results that were Dot even imagined possible when he first learned about the field. His clos- ing words were on what users do and what DOE wants to continue to sup- port -fundamental research.
Cyrus Safinya, University of Cali- fornia a t Santa Barbara, began the
Graduate strident protein crystallograpby poster award recipient, Enriqtte Ritdiiio- Piirera of the Universidad Nncionnl Aritononta de Mexico, poses by his oiuard-winning poster.
Current and Future Science session with a talk on X-ray diffraction stud- ies on liposon,e-DNA interaction, aimed at understanding the interac- tion between lipids and DNA to help develop new drug delivery techniques for gene therapy. A series of experi- ments, performed on beam lines 7-2 and 10-2 at SSRL, has given impor- tant insights on the multilamellar membrane structures formed by lipid molecules and intercalating DNA molecules. Among those is the dis- covery of a two-dimensional hexago- nal lattice phase, HC,,, which is highly transfectant due to its ability to fuse and release DNA upon adhering to anionic vesicles.
Robert Stroud, University of Cali- fornia a t San Francisco, described how new methodologies in molecu- lar biology and synchrotron sciences have been the basis for a leap forward in our understanding of life mecha- nisms using the tools of structural biology. G o i n g i n t o t h e next millenium, new goals are being de- fined and new tools appear on the horizon. Significant advances in all fields related to structural biology, especially the advent of high-inten- sity beam lines equipped with fast detectors and advanced instrumenta- tion, will allow the determination of assemblies of structures and analysis
of complete classes of proteins of particular biological interest or focus area.
Tom Cahill, University of Califor- nia a t Davis, highlighted the growing area of environmental research per- formed a t synchrotron facilities by presenting work performed by his group to define global aerosol trans- port patterns in the atmosphere. Cahill is using synchrotron-based X-ray fluorescence techniques on a 10- to 100-pm-length scale to ana- lyze the chemical compositions of at- mospheric dust particles collected on filter membranes. These studies have led to the discovery of previously unknown atmospheric circulation patterns and better definition of air- borne particle residence times. This information is fundamental to con- structing realistic models of global atmospheric processes such as green- house warming events.
This session also featured Janos Hajdu, University of Uppsala, dis- cussing the possibility of retrieving structural information about a large single molecule from the scattering o f a single extremely intense pulse o f X-rays. In order to measure atomic- scale structure, the puke would need to be so intense as to destroy the molecule. Nevertheless, molecular dynamics calculations indicate that
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X A S W o r k s h o p organizer Ingrid Pickering of SSRL tutors novice users in the E X A FSPA K software practicnl analysis session.
an extremely fast pulse (sub-ps) could extract the information before the sample’s structure i s changed. These studies suggest that a fourth-genera- tion X-ray source, such as the LCLS (see below), should have the required intensity and riming characteristics for measurements of this type.
This talk was followed by Max Cornacchia, SSRL, who gave an up- date of the design status and R&D plan for the 1.5 A SASE-FEL at SLAC called the Linac Coherent Light Source (LCLS). The LCLS is designed to pro- duce 300-fsec-long coherent radiation pulses with 9 GW peak power. This effort is a multi-laboratory collabora- tion between SLAC, the Argonne, Brookhaven, Los Alamos and Lawrence Livermore National Laboratories, and the University of California at Los Angeles.
The Materials Science section con- tained a wide-ranging set of talks. Pe- ter Armitage, Stanford University, de- scribed results on the n-type cuprate superconductor Nd,,, ,Ce0,,5Cu0, showing that the band structure at the Fermi edge does not exhibit the re- marka ble anisotropic leading edge gap that is the hallmark of d-wave‘super- conductivity seen in the p-type super- conductors. Apurva Mehta, SSRL, showed how resonance diffraction can be used to determine chemical shifts in mutivalence (or multiphase) materials since, unlike absorption spectroscopy, it is sensitive to the crystallographic location of the probe element and hence is capable of measuring site and phase specific valences. He then presented resonance powder diffraction data on various Mn oxides including the multi-
valent Mn30,. Finally, Jan Luning, IBM, described how NEXAFS studies were used to determine that the bulk order in perfluoroalkyl substituted polymethacrylates was what ultimately limits the achievable surface order and thus determines the surface properties of this polymer. These polymers are widely used low surface-energy coat- ings or anti-wetting agents whose prop- erties are believed to arise from segre- gation of CF, groups to the surface. However, until now, proof of a direct correlation between the surface ener- gies and surface structure and the or- der in the underlying bulk had been lacking.
Talks in the Environmental Sciences session highlighted the increasing role of SR-based environmental research in science-based policy and technology development in the US. Satish Myneni, Lawrence Berkeley National Labora- tory, presented CI K-edge XAS mea- surements suggesting that a wide vari- ety of chlorinated organic compounds are produced naturally in the environ- ment via plant and/or microbial meta- bolic processes. This conclusion is highly significant because it calls into question the basis for maximum con- centration limits set by the Environ- mental Protection Agency for these often toxic compounds in the environ- ment. Chris Fuller, US Geological Sur- vey, presented a case example in which SR-based XAS and XRD measurements have provided information fundamen- tal to the design of in-situ remediation technologies for removing uranium contamination from groundwater at sites in the western US. These studies show that the primary mechanism of uranium attenuation in phosphate- based chemical reactive barriers is ad- sorption of uranium onto barrier ma- terial surfaces and not precipitation of U(V1)-phosphate phases or cation ex- change processes. These conclusions lead directly to barrier designs modi- fied to exploit this mechanism, such as single-piece barrier units that function as filters that can be removed, cleaned and returned to use.
In thesession on Structural Molecu- lar Biology, three new protein crystal structures were presented- two solved by MAD and one by a xenon deriva-
tive. Frank Whitby, University of Utah, discussed the structure of FIiG, a pro- tein that forms part of the “motor” at the base of bacterial flagella. The mo- tor consists of two rings, a stationary outer one and the inner ring that ro- tates with the flagellum. FliG is part of the inner ring and is implicated in the torque-generating process. Thus the structure provides insight into the mechanism of the motor’s action. Paul Ellis, SSRL, presented the structure of arsenite oxidase, an enzyme used by bacteria to reduce the toxicity of arsen- ite. Arsenite oxidase has a M o binding site and 2 Fe-S clusters, one of which of a type that is novel to Mo-containing protein. The value of using high pres- sure xenon gas to make heavy-atom derivatives was highlighted by Zusua Hamburger, California Institute of Technology, in her talk about solving the structure of the invasin, a bacterial protein that helps bacteria invademam- malian cells by binding to a receptor protein on the cell surface. The struc- ture shows that invasin mimics the binding surface of the mammalian pro- tein fibronectin even though the amino acid sequence and folding pattern are very different. Invasin thus presents a dramatic example of convergent evo- lution.
A poster session was held the first evening with over 40 contributions fea- turing a variety of science at SSRL as well as 13 vendors showcasing their latest instruments. Four graduate s tu- dents were the recipients of the annual poster awards (consisting of a ribbon and $75 each) in four discipline areas: materials science, environmental sci- ence, protein crystallography and bio- logical spectroscopy. These awards were presented during the banquet by outgoing SSRL Users’ Organization Chair Patrick Allen of Lawrence Livermore Nat iona l Laboratory. Awards went t o Serena DeBeer, Stanford Ihiversity, for “X-ray Ab- sorption Spectroscopic Studies on the Native Inter mediate of La cca se ” ; Stephen Prilliman, University of Cali- fornia a t Berkeley, for “Solid-Solid Phase Transitions of Large Nanocrys- tals and Nanorods”; Enrique Rudiiio- Piiiera, National Automonous Univer- sity of Mexico, for “Crystallographic
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Studies on the Allosteric Enzyme Glu- cosamine 6-Phosphate Deaminase from Different Sources”; and Kaye Savage, Stanford University, for “Character- ization of Synthetic and Natural Arsenian Jarosite Using Synchrotron X-ray Techniques.” Allen also an- nounced the newly elected SSRLUO members, Paul Alivisatos, University of California a t Berkeley; Corwin Booth, Lawrence Berkeley National Laboratory; and Marilyn Olmstead, University of California a t Davis.
Also during the banquet, a casual on-site barbecue, the Second Annual Farrel W. Lytle Award, given in recog- nition for outstanding contributions to synchrotron radiation research at SSRL, was presented to Tom Hostetler, an 18-year veteran of SSRL. Hostetler was recognized for his contributions as a duty operator, beam line technician and X-ray operation group member providing top-notch customer service to users and for his mentoring of young students and engineers. The presenta- tion included several of Hostetler’s co- workers entertaining conference attend- ees with stories detailing how his dedication to users and getting the job done was accomplished in often hu-
morous ways. This concluded with a presentation by Piero Pianetta of a new compound, “Tomiurn”-a glitterysub- stance that slipped through the fin- gers-and a chainsaw to assist him in cutting through “red tape” when as- sisting users.
The conference concluded with two concurrent workshops, “Fundamentals of X-ray Absorption Spectroscopy Data An a 1 y s i s , ” organized by Ingr id Pickering and Matthew Latimer of SSRL, and “Small-angle X-ray Scatter- ing Studies at SSRL,” organized by John Pople, also of SSRL. The XAS workshop, attended by approximately 53 people, commenced with a dernon- stration session of the EXAFSPAK suite of software by its author, Graham George of SSRL. Aspects of data cali- bration and averaging, pre-edge and spline subtraction and Fourier trans- forms were covered. The participants then divided into two groups. One group engaged in a practical analysis session using 12X-terminals and work- stations with tutors present to assist participants and answer questions and printed “worked examples” were pro- vided. The other group remained be- hind for a lively question and answer
session with Dr. George, giving them an opportunity to ask more in-depth questions about EXAFSPAK applica- tions. Thus, the workshop was instruc- tive not only for newcomers but also for those who had more experience with the software.
The small angle X-ray scattering workshop comprised a series of semi- nars in which contemporary SAXS data a n d techniques were discussed. Amongst the invited speakers were Juani ta Wickham and Stephen Prilliman, both of University of Cali- fornia a t Berkeley, who presented their ongoing work in semiconductor nanocrystal growth and offered ge- neric advice on the configuration of X-ray scattering experiments. James Hedrick, IBM, discussed the advan- tages of SAXS for the design of novel macromolecular dendrimers, and the new SAXS facility available at SSRL was also presented.
Invited talk and poster abstracts can be obtained by contacting SSRL User Research Administration at +1- 650-926-2079. W
AUDREY ARCHULETA SSRL
Synchrotron Radiation Instrumentation Conference
The 1 lth US National Synchrotron Radiation Instrumentation Confer- ence (SRI99), hosted by the Stanford Synchrotron Radiation Lasoratory (SSRL) in Stanford, California, was held on October 13-15, 1999. At- tendees from over 60 organizations- more than 230 participants-gath- ered at this forum to present and discuss recent developments a t the eight US synchrotron radiation re- search facilities. Conference chairs for SRI99 were Piero Pianetta and Herman Winick of SSRL assisted by a program committee representing all US synchrotron facilities.
The intense activity in creating new light sources and improving existing sources in the US and Canada was covered in the opening session on New Facilities and Major Upgrades. A highlight of this session included a report by Les Dallin on the Canadian Light Source (CLS), a new third gen- eration light source facility now in construction at the Saskatoon Accel- erator Laboratory at the University of Saskatchewan, Canada. The ori- gins of this project go back to 1990 when the Canadian Institute for Syn- chrotron Radiation was formed. In May 1996, an international peer re-
view committee recommended that the CLS be built; funding came in March 1999. The CLS design is for a 2.9 GeV, 500 mA ring with a circum- ference of 171 m, 12 straight sections and a horizontal emittance of 18 nm- radians. The plan is t o construct an initial complement of 12 beam lines, 15 experimental stations on four bending magnet source points, four undulators and two wigglers. Com- missioning of the new ring is sched- uled for 2003.
Also included in this session was a report by Bob Hettel, SSRL, on the start. of construction of SPEAR3 a t the SSRL. The project is jointly funded by the US National Institutes of Health (NIH) and the Department of Energy (DOE). Initial funding for this project was received from the NIH in mid-1999. The project involves an upgrade of the injection system from
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