Spin-Filtering Studies at COSY

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Bartholomew Richards
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1 Mitglied der Helmholtz-Gemeinschaft Spin-Filtering Studies at COSY Proposal and beam request #199 PAX collaboration 6. September 2009 Mikhail Nekipelov

2 Outline Spin-filtering. Polarisation buildup at COSY. Status of machine acceptance studies (proposal #198). PAX-at-COSY. Measurements. Time plan. 6. September 2009 Folie 2

3 Polarisation Build-up of the stored beam in 2 sub states: up/down selective loss remove one substate more than the other selective flip Reverse one substate more than the other 6. September 2009 Folie 3

4 Polarisation Build-up of the stored beam in 2 sub states: up/down selective loss remove one substate more than the other selective flip Reverse one substate more than the other PLB 674 (2009) September 2009 Folie 4

5 Spin Filtering (Selective Loss) Polarisation build-up of an originally unpolarised particle beam by repeated interaction with polarised hydrogen target, e.g. in a storage ring: unpolarised beam polarised beam polarised target 6. September 2009 Folie 5

6 Cross Sections σ tot = σ 0 + σ 1 P Q + σ 2 (P k)(q k) P beam polarisation Q target polarisation k beam direction max dσ σ1 2π (Axx Ayy)d dω 0 ~ TSR measurement Longitudinal σ ~ 1 2π max acc dσ dω (A xx A yy )d Transverse N.Nikolaev, arxiv:hep-ph/ September 2009 Folie 6

7 σ 0 [mb] σ 1 [mb] Spin-flip Cross Sections Θ acc [mrad] Θ acc [mrad] Δσ 0,1 << σ 1 (>Θ acc ) 6. September 2009 Folie 7

8 Acceptance of the Cooled Beam (2008) NIM A 441 (2000) 54 acc x y Θ acc =2.14±0.15 mrad 6. September 2009 Folie 8

9 y' (mrad) y' (mrad) Principle of the Measurement y (mm) 4 y (mm) NIM A599 (2009) 130 Fig. 11. y-y' phase space at the ANKE interaction point at 2.65 GeV with a machine acceptance of A y = 25 π mm mrad, and a beam emittance of y = 3.8 π mm mrad (left panel). When the aperture is moved into the machine acceptance (right panel), the reduced maximum allowed y' leads to smaller beam lifetime. Geometrical COSY acceptance ~ 40 p mm mrad 6. September 2009 Folie 9

10 Beam current (a.u.) Beam current (a.u.) Acceptance of the Uncooled Beam (2008) A x =(23.7±2.4)µm Electron beam reduces machine acceptance X (s) Y (s) A y =(15.7±1.3)µm Dynamic effects are believed to be responsible for the difference with the geometrical value 6. September 2009 Folie 10

11 COSY Orbit Correction Orbit response matrix method, PhD thesis D.Welsch 6. September 2009 Folie 11

12 Working Point 6. September 2009 Folie 12

13 Acceptance of the Cooled Beam Acceptance of the cooled and uncooled beam: A x = A y = 25 p mm mrad Improvement is due to the minimisation of the orbit distortions. Electron cooler does not restrict machine acceptance. No special care has been taken to establish good vacuum conditions for these studies. Acceptance angle at PAX target position: acc = 8.4 mrad 6. September 2009 Folie 13

14 Polarisation Buildup Transverse Longitudinal COSY cooling range Strong dependence on COSY vacuum need for improvement 6. September 2009 Folie 14

15 COSY Ring 6. September 2009 Folie 15

16 PAX-at-COSY Main purpose: 1. Quantitative understanding of the polarisation buildup 2. Commissioning of the experimental setup for AD COSY-Quadupoles ABS Target chamber with storage cell and detector system BRP Low-β quadrupoles (CELSIUS) 6. September 2009 Folie 16

number of events number of events Measurements (Transverse Case) o

measure beam or target polarisation Use dp at T d =98.

=49.3 MeV to measure beam polarisation dp at T d =98.

17 number of events number of events Measurements (Transverse Case) o o o pp analysing powers are very small and cannot be used to measure beam or target polarisation Use dp at T d =98.6 MeV to measure target Q After spin-filtering in pp use pd at T p =49.3 MeV to measure beam polarisation dp at T d =98.6 MeV pd at T p =49.3 MeV cell region cell region vertex z [mm] vertex z [mm] 6. September 2009 Folie 17

18 Polarisation Evolution Transverse T=49.3 MeV t l 4 measurement points are needed (2 per target spin state) in order to determine the slope 6. September 2009 Folie 18

19 Count Rates (6h filtering + 0.5h cycle) * 8.5h measurement / 0.5h cycle = 5 days 6. September 2009 Folie 19

20 Anticipated Time Plan COSY st COSY Proposal submitted Installation of low-β insertion 2 nd Commissioning of the low-β section, and vacuum improvement Machine acceptance measurement AD CERN Proposal submitted July 2009 CERN Research board decision st Installation of the target chamber, cryo pump, ABS, BRP, holding field, collimators, fixed cell etc. Commissioning and measurement of the acceptance angle 2 nd Installation of COSY detection system Measurement of the target polarisation in dp and pd elastic scattering Spin-filtering at COSY with transverse polarisation st Spin-filtering at COSY with transverse polarisation (continued) Installation of the AD low-β insertion Commissioning of the AD low-β insertion AD user compatibility PAX optics 2 nd Installation of the target chamber and scraper system st Implementation of solenoid(s) in injection beam line Installation of ANKE ABS and AD detector at TP1 Commissioning of the AD detector with openable cell 2 nd Spin-filtering at COSY with longitudinal beam using ecooler + WASA solenoids st Implementation of the ½ AD Siberian snake at ANKE Commissioning of the AD Siberian snake Spin-filtering with longitudinal beam Machine acceptance studies Stacking studies Installation of PAX ABS and BRP Installation of openable storage cell and detection system Measurement of H and D target polarisation with pbar beam Spin-filtering using H and D target below 70 MeV, transverse polarisation 2 nd Implementation of 300 kev ecooler st Commissioning of ecooler with beam 2 nd Spin-filtering with H and D target below 430 MeV with transverse polarisation 2015 Implementation of the Siberian snake 2016 PAX optics with Siberian snake Spin-filtering measurements with H and D target below 430 MeV with longitudinal polarisation, including commissioning of the Siberian snake. 6. September 2009 Folie 20

21 Anticipated Time Plan COSY st COSY Proposal submitted Installation of low-β insertion 2 nd Commissioning of the low-β section, and vacuum improvement Machine acceptance measurement st Installation of the target chamber, cryo pump, ABS, BRP, holding field, collimators, fixed cell etc. Commissioning and measurement of the acceptance angle 2 nd Installation of COSY detection system Measurement of the target polarisation in dp and pd elastic scattering Spin-filtering at COSY with transverse polarisation st Spin-filtering at COSY with transverse polarisation (continued) AD CERN Proposal submitted July weeks CERN Research board decision 2 weeks Installation of the AD low-β insertion 2+4 weeks Commissioning of the AD low-β insertion AD user compatibility PAX optics 2 nd Installation of the target chamber and scraper system st Implementation of solenoid(s) in injection beam line Installation of ANKE ABS and AD detector at TP1 Commissioning of the AD detector with openable cell 2 nd Spin-filtering at COSY with longitudinal beam using ecooler + WASA solenoids st Implementation of the ½ AD Siberian snake at ANKE Commissioning of the AD Siberian snake Spin-filtering with longitudinal beam Machine acceptance studies Stacking studies 4 weeks 1+4 weeks Installation of PAX ABS and BRP Installation of openable storage cell and detection system Measurement 3 weeks of H and D target polarisation with pbar beam Spin-filtering using H and D target below 70 MeV, transverse polarisation 2 nd Implementation of 300 kev ecooler st Commissioning of ecooler with beam 2 nd Spin-filtering with H and D target below 430 MeV with transverse polarisation 2015 Implementation of the Siberian snake 2016 PAX optics with Siberian snake Spin-filtering measurements with H and D target below 430 MeV with longitudinal polarisation, including commissioning of the Siberian snake. 6. September 2009 Folie 21

22 The COSY Low-b Section July 2009 installation of the PAX Low-β Section at COSY: Vacuum: New section 1.2, NEG-coated beam-line, fast shutters Magnets: 4 CELSIUS quadrupoles, 4 steerer magnets 6. September 2009 Folie 22

23 COSY Low-b Section: Vacuum Installation 2xTS Fast Shutters NEG 5000 l/s NEG 5000 l/s BPM IG 100 l/s IG 100 l/s BPM BPM IG 100 l/s IG 100 l/s 6. September 2009 Folie 23

24 Commissioning 2009/10 Develop PAX optics up to 135 MeV Use steerers to keep beam on axis Measure machine acceptance Long beam life time without target (better COSY vacuum needed) 6. September 2009 Folie 24

25 individual beam requests Anticipated Time Plan COSY st COSY Proposal submitted Installation of low-β insertion 2 nd Commissioning of the low-β section, and vacuum improvement Machine acceptance measurement st Installation of the target chamber, cryo pump, ABS, BRP, holding field, collimators, fixed cell etc. Commissioning and measurement of the acceptance angle 2 nd Installation of COSY detection system Measurement of the target polarisation in dp and pd elastic scattering Spin-filtering at COSY with transverse polarisation AD CERN Proposal submitted July weeks CERN Research board decision 2 weeks Installation of the AD low-β insertion 2+4 weeks st Spin-filtering at COSY with transverse polarisation (continued) Commissioning of the AD low-β insertion AD user compatibility PAX optics 2 nd Installation of the target chamber and scraper system st Implementation of solenoid(s) in injection beam line Installation of ANKE ABS and AD detector at TP1 Commissioning of the AD detector with openable cell 2 nd Spin-filtering at COSY with longitudinal beam using ecooler + WASA solenoids st Implementation of the ½ AD Siberian snake at ANKE Commissioning of the AD Siberian snake Spin-filtering with longitudinal beam Machine acceptance studies Stacking studies 4 weeks 1+4 weeks Installation of PAX ABS and BRP Installation of openable storage cell and detection system Measurement 3 weeks of H and D target polarisation with pbar beam Spin-filtering using H and D target below 70 MeV, transverse polarisation 2 nd Implementation of 300 kev ecooler st Commissioning of ecooler with beam 2 nd Spin-filtering with H and D target below 430 MeV with transverse polarisation 2015 Implementation of the Siberian snake 2016 PAX optics with Siberian snake Spin-filtering measurements with H and D target below 430 MeV with longitudinal polarisation, including commissioning of the Siberian snake. 6. September 2009 Folie 25

26 Installation 2010 Target chamber with 3 additional fast shutters (ABS, BRP and UGSS) Weak holding field coil system Openable collimators Cryo pump ABS BRP COSY-PAX interlock system NEG-activation (230 C) Rail system for installation of detection system COSY detection system with fixed storage cell 6. September 2009 Folie 26

27 individual beam requests Anticipated Time Plan COSY st COSY Proposal submitted Installation of low-β insertion 2 nd Commissioning of the low-β section, and vacuum improvement Machine acceptance measurement AD CERN Proposal submitted July weeks Present beam request CERN Research board decision st Installation of the target chamber, cryo pump, ABS, BRP, holding field, collimators, fixed cell etc. Commissioning and measurement of the acceptance angle 2 nd Installation of COSY detection system Measurement of the target polarisation in dp and pd elastic scattering Spin-filtering at COSY with transverse polarisation 2 weeks Installation of the AD low-β insertion 2+4 weeks st Spin-filtering at COSY with transverse polarisation (continued) Commissioning of the AD low-β insertion AD user compatibility PAX optics 2 nd Installation of the target chamber and scraper system st Implementation of solenoid(s) in injection beam line Installation of ANKE ABS and AD detector at TP1 Commissioning of the AD detector with openable cell 2 nd Spin-filtering at COSY with longitudinal beam using ecooler + WASA solenoids Machine acceptance studies Stacking studies 4 weeks 1+4 weeks Installation of PAX ABS and BRP individual st Implementation of the ½ AD Siberian snake at ANKE Commissioning of the AD Siberian snake Spin-filtering with longitudinal beam Installation of openable storage cell and detection system Measurement 3 weeks of H and D target polarisation with pbar beam Spin-filtering using H and D target below 70 MeV, transverse polarisation 2 nd Implementation of 300 kev ecooler Σ = 22 weeks st Commissioning of ecooler with beam 2 nd Spin-filtering with H and D target below 430 MeV with transverse polarisation 2015 Implementation of the Siberian snake 2016 PAX optics with Siberian snake Spin-filtering measurements with H and D target below 430 MeV with longitudinal polarisation, including commissioning of the Siberian snake. 6. September 2009 Folie 27

Spin Filtering at COSY - First Results

Mitglied der Helmholtz-Gemeinschaft Spin Filtering at COSY - First Results Dieter Oellers University of Ferrara, INFN Ferrara STORI11, Frascati PAX-Collaboration Goal: Produce a beam of polarized antiprotons