Embed Size (px)
Citation preview
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
PAXStatus and future plan
June 26, 2012 | Alexander Nass
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
2June 26, 2012 SPIN Physics Workshop in Gatchina
OverviewCOSY
PAX
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
3
2006 transport of the HERMES polarized target (Atomic Beam Source (ABS) and Breit-Rabi Polarimeter (BRP)) to Jülich
2006-2009 rebuilding of the ABS and BRP for the use at COSY / AD and design & construction of the target chamber
2008-2012 Construction of an openable storage cell 2009 Installation of the low-β section, commissioning 2010 Installation of the target section at COSY, commissioning 2010-2011 Design, construction and installation of the NEG
pump attached to the target chamber 2011 transverse Spin Filter experiment at COSY
June 26, 2012 SPIN Physics Workshop in Gatchina
History
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
4June 26, 2012 SPIN Physics Workshop in Gatchina
The polarized target
Production of a polarized atomic beam by an ABS Increase of the target density by means of a storage cell Analysis of target polarization by a BRP and TGA Calibration of the BRP by pp-scattering data
ABS
BRP
The polarized target in LKW-Schleuse
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
5June 26, 2012 SPIN Physics Workshop in Gatchina
The target chamber Accomodation of the (openable)
storage cell and multipurpose detector in a compact design
Support of the target holding field coils
High pumping speed for target gas
Fast shut-off valves to separate and protect COSY vacuum
Large flanges to install the complete detector / target cell setup in one operation on a rail system
Fixed flow limiters to reduce gas flow into the adjacent sections
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
6June 26, 2012 SPIN Physics Workshop in Gatchina
The (openable) storage cell Storage cell necessary to
increase target gas density up to 1014 atoms/cm2
Storage cell walls should suppress recombination and depolarization
Openable storage cell to allow the uncooled AD beam to pass
Teflon foil walls to detect low energy recoils and suppress recombination and depolarization
Fixed cell used in the COSY experiments due to problems with the density in the openable cell
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
7June 26, 2012 SPIN Physics Workshop in Gatchina
The low-β section Low-β section necessary to increase
the acceptance angle to about 6 mrad Small diameter COSY proton beam
allows the use of a storage cell and therefore an increased filtering rate
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
8June 26, 2012 SPIN Physics Workshop in Gatchina
Commissioning of the low-β section and machine development
Injection of COSY beam through the fixed cell possible
Using frame system acceptance angle measured to be 6.1 mrad
Established sufficient long beam lifetimes > 7000s without target gas with 1010 protons at the desired energy of 49.3 MeV
The frame system
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
9June 26, 2012 SPIN Physics Workshop in Gatchina
The NEG pump High pumping speed in the target chamber
necessary to reduce the pressure of the unpolarized H2 / D2 gas in the target chamber and adjacent beam line sections
Therefore allowing longer beam lifetimes of the COSY proton beam
Commercially available NEG cartridges mounted into a bakeable stainless steel box
Box is closeable with a jalousie to protect the target cell and detector from the heat when NEG is activated (T=250…400 °C)
Measurements during the spin filter beam time showed pumping speeds of 13000 l/s
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
10June 26, 2012 SPIN Physics Workshop in Gatchina
Installation at COSY Installation of the target section in COSY in summer 2010 Modular system to remove and install the target quickly One support structure for ABS, BRP and target chamber with NEG pump Rail system for installation of the flange with target cell and future detector
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
11June 26, 2012 SPIN Physics Workshop in Gatchina
Density of the polarized target gas
In addition target thickness measurement using the beam energy loss method which is deduced from a shift of the orbit frequency of the coasting beam:d
Intensity measurement of the ABS using an absolute baratron pressure measurement in the center on the storage cell in comparision with a calibrated flux from an unpolarized gas feed system
IH2 = (3.0±0.1)·1016 H2/s
IH1 = (6.1±0.3)·1016 H/s
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
12June 26, 2012 SPIN Physics Workshop in Gatchina
Polarization of the target gasAverage target polarization:
Hydrogen atomic fraction:
Atomic polarization:
Polarization injected into the storage cell:
Measured polarization in the BRP:
Assuming the most probable, uniform distribution
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
13June 26, 2012 SPIN Physics Workshop in Gatchina
Transverse Spin Filtering at COSY
For more information see talk of D.Oellers
Successful spin filter experiment in autumn 2011
8 weeks of data taking All components worked well without
major problems at a high performance level
Preliminary result for the spin filtering cross section for pp interaction
Result is in good agreement with the theoretical predictions and confirms the present understanding of the underlying processes
Preliminary
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
14June 26, 2012 SPIN Physics Workshop in Gatchina
Future plan September 2012 TRIC test experiment using the PAX-target October 2012 Removal of the PAX-target from COSY ring 2012-2013 Modification and commissioning of the polarized
internal target for running with H and D 2012-2013 Design and construction of a multipurpose detector 2013 Installation of the Siberian Snake at COSY PAX site for
ANKE experiment(s) with longitudinal beam polarization 2014 Installation of the Siberian Snake at COSY ANKE site
and reinstallation of the PAX target with detector 2014-2015 Longitudinal Spin Filter experiment at COSY 2015-2017 TRIC and pd breakup experiments with PAX 20?? Spin filtering with antiprotons at AD/CERN or FAIR
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
15June 26, 2012 SPIN Physics Workshop in Gatchina
Modifications on the polarized target
TRIC and pd breakup need D target Preparation of hardware and software for
D Comissioning of target section with D
outside COSY
p filtering requires H & D in short sequence
Prototype of new type RF cavity (dual cavity) was produced and tested with RF-generator bridge
Has to be tested with H / D beamHydrogen
Deuterium
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
16June 26, 2012 SPIN Physics Workshop in Gatchina
The Multipurpose Detector
For more information see talk of C.Weidemann
Silicon strip detector with 3 layers
Readout electronics connected directly in vacuum
Liquid cooling system for detectors and electronics
Openable cell included in the design
Complete setup attached to one flange of the target chamber
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
17June 26, 2012 SPIN Physics Workshop in Gatchina
Openable Flow Limiters
Flow limiters necessary to reduce flow of hydrogen (target) gas into adjacent beam tubes with high β-functions of the (anti)proton beam
High gas pressures lead to reduced beam lifetimes of the (anti)proton beam
Openable flow limiters necessary since uncooled (anti)proton beam is large (up to 100mm diameter)
After beam cooling (diameter <10mm), closing of flow limiters to acceptance limit and injection of target gas
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
18June 26, 2012 SPIN Physics Workshop in Gatchina
Will allow for flexible use in two locations
Fast ramping (< 30 s) with injection of Py
Cryogene free system
Snake should be available in 2012 / 2013
ANKE
PAXPAX
ANKE
The Siberian Snake
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
19June 26, 2012 SPIN Physics Workshop in Gatchina
Preparations for PAX @ AD/CERN
PAX target section
Electron cooler
Siberian snake
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
20June 26, 2012 SPIN Physics Workshop in Gatchina
Preparations for PAX @ AD/CERN
Atomic Beam Source
Six additional quadrupolesBreit-Rabi
Polarimeter
Target chamber:Detector system + storage cell
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
21June 26, 2012 SPIN Physics Workshop in Gatchina
Preparations for PAX @ AD/CERN
PAX low-β section for AD ready for installation
Mitg
lied
der
Hel
mho
ltz-G
emei
nsch
aft
22June 26, 2012 SPIN Physics Workshop in Gatchina
Collaboration members in [email protected] r, L. Barion c, S. Barsov d, U. Bechstedt a,b, P. Benati c, S. Bertelli c, V. Carassiti c, D. Chiladze e, G. Ciullo c,M. Contalbrigo c, P.F. Dalpiaz c, S. Dymov g,h, R. Engels a,b, W. Erven i,b, M. Fiorini c, M.Gaisser a,b, R. Gebel a,b, P. Goslawski j, K. Grigoryev d,a,b, G. Guidoboni c, A. Kacharava a,b, A. Khoukaz j, A. Kulikov h, G. Langenberg a,b, A. Lehrach a,b, P. Lenisa c, N. Lomidze e, B. Lorentz a,b, G. Macharashvili h, R. Maier a,b, B. Marianski r, S. Martin a,b, D. Mchedishvili e, S. Merzliakov h,a,b, I.N. Meshkov h, H.O. Meyer k, M. Mielke j, M. Mikirtychiants d,a,b, S. Mikirtychiants d,a,b, A. Nass g,a,b, M. Nekipelov a,b, N.N. Nikolaev a,b,l, M. Nioradze e, D. Oellers a,b,c, M. Papenbrock j, L. Pappalardo c, A. Pesce c, A. Polyanski a,b,f, D. Prasuhn a,b,F. Rathmann a,b, J. Sarkadi a,b, R. Schleichert a,b, A. Smirnov h, H. Seyfarth a,b, V. Shmakova h, M. Statera c, E. Steffens g, H.J. Stein a,b, H. Stockhorst a,b, H. Straatmann m,b, H. Ströher a,b, M. Tabidze e, G. Tagliente n, P. Thorngren Engblom o, S. Trusov p,q, A.Trzcinski r, Y. Valdau a,b,d, A. Vasilyev d, Chr. Weidemann a,b,c, K.M.von Würtemberg o, P. Wüstner i,b, P. Zupranski r
a Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germanyb Jülich Center for Hadron Physics, 52425 Jülich, Germanyc Università di Ferrara and INFN, 44100 Ferrara, Italyd St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russiae High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgiaf Institute for theoretical and experimental physics, 117218 Moscow, Russiag Physikalisches Institut II, Universität Erlangen-Nürnberg, 91058 Erlangen, Germanyh Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russiai Zentralinstitut für Elektronik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germanyj Institut für Kernphysik, Universität Münster, 48149 Münster, Germanyk Physics Department, Indiana University, Bloomington, IN 47405, USAl L.D. Landau Institute for Theoretical Physics, 142432 Chernogolovka, Russiam Zentralabteilung Technologie, Forschungszentrum Jülich GmbH, 52425 Jülich, Germanyn INFN, Sezione di Bari, 70126 Bari, Italyo Royal Institute of Technology, Physics Department, SE-10691 Stockholm, Swedenp Institut für Kern- und Hadronenphysik, Forschungszentrum Rossendorf, 01314 Dresden, Germanyq Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow, Russiar National Centre for Nuclear Reserch, 00681 Warsaw, Poland
