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Polarized beam in RHIC in Run 2011. Polarimetry at RHIC A.Zelenski, BNL

Polarized beam in RHIC in Run 2011. Polarimetry at RHIC A.Zelenski, BNL. PSTP 2011, September 13, St.Petersburg. RHIC: the “Polarized” Collider. Polarization facilities at RHIC. Design goal - 70% Polarization L max = 1.6  10 32 s -1 cm -2 50 < √ s < 500 GeV.

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Polarized beam in RHIC in Run 2011. Polarimetry at RHIC A.Zelenski, BNL

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  1. Polarized beam in RHIC in Run 2011.Polarimetry at RHICA.Zelenski, BNL PSTP 2011, September 13, St.Petersburg

  2. RHIC: the “Polarized” Collider Polarization facilities at RHIC. Design goal - 70% Polarization L max = 1.6  1032 s-1cm-2 50 < √s < 500 GeV RHIC pC “CNI” polarimeters Absolute H-jet polarimeter RHIC PHENIX STAR Siberian Snakes Spin Rotators 5% Snake Pol. H- ion source LINAC AGS, 24GeV AGS pC “CNI” polarimeter 200 MeV polarimeter 20% Snake

  3. Higher polarization out of AGS (jump quads). Higher polarization at RHIC store (new working point, tune/orbit feedback on the ramp). Highest peak luminosity ~1.6∙1032 cm-2 s-1 in RHIC so far (9MHz, orbit/tune). Orbit feedback works. We have excellent orbit control on the ramp. 9MHz cavity is operational. No indication of intensity limit. 10Hz orbit feedback works. Beneficial to luminosity. Chromaticity feedback works for these ramps. Essential for the down ramp development. Progress in 2011 polarized proton Run.

  4. Tune jump system in AGS

  5. Polarization at injection in RHIC with the Jump-Quads in operation.

  6. RHIC luminosity in Run-2011 Peak luminosity ~1.5*1032 cm2 s Bunch intensity ~ 1.6 *1011 proton/bunch

  7. RHIC polarized protons 2000-2011 Run 2011,250 GeV, P-53% Wolfram Fischer 7

  8. Polarimetry at RHIC • Faraday rotation polarimeter • Lamb-shift polarimeter • 200 MeV - absolute polarimeter • AGS p-Carbon CNI polarimeter • RHIC p-Carbon CNI polarimeter • RHIC - absolute H-jet polarimeter • Local polarimeters at STAR and PHENIX • Y.Makdisi, A.Poblaguev talks

  9. Faraday rotation polarimeter of Rb vapor. Linear polarized probe laser beam at 780 nm. Θp-optical pumping –on. Θ0-optical pumping -off. Rb-cell PD1 λ/2 PD2 Cr:LISAF pumping laser at795 nm PD1=I0 sin θp PD2=I0 cos θp PRb= (θp- θ0)/ θ0

  10. Proton Lamb-shift polarimeter at3-35keV beam energy. . H-→ H+→ H(2S) La(10.2eV) -121.6 nm • N+ =N0(1+P) / 2 • N- = N0(1-P) / 2 • P=2 (N+-N-)/(N+ +N-) H(2S) B=575 G

  11. Layout of the 200 MeV proton polarimeter, (2010) 16.2 deg

  12. Proton-Carbon Elastic Scattering at 200 MeV.

  13. Ay=99.96+/0.02%

  14. Detector and variable absorber setup for 200 MeV proton beam.

  15. GEANT calculation of pC polarimeter for 200MeV proton beam Ep=194.3MeV inelastic Ep=198.7MeV elastic

  16. Measured Analyzing Power vs length of absorber. Ay(pC) =0.62+/-0.02

  17. AGS CNI Polarimeter 2011 Carbon target 90º in Lab frame Recoil carbon Polarized proton 3 different detector types: 1,8 - Hamamatsu, slow preamplifiers Larger length (50 cm) 2,3,6,7 - BNL, fast preamplifiers Regular length (30 cm) 4,5 - Hamamatsu, fast preamplifiers Run 2009: BNL, slow preamplifiers Outer Inner A.Poblaguev talk 11 February 2011 RHIC Spin Collaboration Meeting Spin Meeting 17

  18. Three complimentary pillars of the RHIC polarimetry. • p-Carbon CNI polarimeter: relative, fast, polarization profiles, bunch-by bunch measurements, polarization decay time. • Proton-proton H-jet CNI polarimeter: absolute, integral, about 5-7% statistical accuracy in one store. • Local polarimeters: relative, fast, integral, bunch-by-bunch, polarization decay time.

  19. RHIC: the “Polarized” Collider Polarization facilities at RHIC. Design goal - 70% Polarization L max = 1.6  1032 s-1cm-2 50 < √s < 500 GeV RHIC pC “CNI” polarimeters Absolute H-jet polarimeter RHIC PHENIX STAR Siberian Snakes Spin Rotators 5% Snake Pol. H- ion source LINAC AGS, 24GeV AGS pC “CNI” polarimeter 200 MeV polarimeter 20% Snake

  20. PHENIX Local Polarimeter Blue Yellow Blue Yellow Blue Yellow Asymmetry vs φ Spin Rotators OFF Vertical polarization Spin Rotators ON Current Reversed Radial polarization Spin Rotators ON Correct Current ! Longitudinal polarization! Monitors spin direction in PHENIX collision region

  21. Beam polarization. Polarization profiles. • Polarization measurements for accelerator setup and monitoring. Depolarization minimization in AGS and RHIC. Relative (on-line) measurements. • Polarization loss from intrinsic resonances: polarization lost at edge of beam → polarization profiles. • Polarization measurements for experimental data normalization (off-line absolute values obtained after detail calibration and normalization). Corrections for polarization profiles.

  22. Hydrogen Gas Jet and Carbon Ribbon Targets. Carbon Ribbon Target Gas Jet Target Beam Cross Section  Carbon Ribbon: ~ 5-10 µm wide 25nm thickness ~ 5 µg/cm2 FWHM~7 mm Average Pave Peak Ppeak and average polarization

  23. H-Jet polarimeter. Elastic scattering: Interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region. Forward scattered proton RHIC proton beam H-jet target recoil proton <5% Ptarget is measured by Breit- Rabi Polarimeter A.S. Belov, A. N. Zelenski, SPIN2008, USA

  24. Spin filtering technique. Atomic Beam Sources. permanent magnet sextupole - 1.7 T gradient 5.7 T/cm Hydrogen atoms with electron polarization: mJ=+1/2 trajectories. Breit-Rabi polarimeter RHIC beam crossing RF transition, polarization transfer from electrons to protons Electron magnetic moment is 659 times Larger than proton :e / P ~659. Focusing strength: ~ (dB/dr)e A.S. Belov, A. N. Zelenski, SPIN2008, USA

  25. H-jet, Blue beam, 250 GeV, Run-2011

  26. H-jet, Yellow beam, 250 GeV, Run 2011

  27. H-jet is an ideal polarimeter ! Problem. Polarization dilution by H2, H2O and other residual gases. Largest source of systematic error. A.S. Belov, A. N. Zelenski, SPIN2008, USA High (~4.5%) analyzing power in a wide energy range (23-250 GeV). High event rate due to high intensity (~100 mA) circulated beam current in the storage ring (~6% statistical accuracy in one 8hrs. long fill). High polarized H-jet density in RHIC ABS. Non-destructive. No scattering for recoil protons. Clean elastic scattering event identification. Direct calibration with Breit-Rabi polarimeter. Most of the false asymmetries are cancelled out in the ratio: P beam =( 1/A)Beam asym / Target asym

  28. H-jet as a luminescence beam intensity monitor.

  29. Carbon target 90º in Lab frame Recoil carbon Polarized proton p-Carbon Polarimetry at RHIC

  30. Measurements with p-Carbon CNI polarimeter. Polarization, polarization profile measurements in the scanning mode. Polarization losses during acceleration and store. Polarization decay during store. Beam intensity profile (emttance) including bunch-by-bunch. Emittance measurements cross-calibrations. Emittance measurements on the ramp.

  31. The RHIC p-Carbon CNI polarimeter. 6 1 2 5 Run04 3 4 Ebeam = 100 GeV Elastic scattering: interference between electromagnetic and hadronic amplitudes in the Coulumb-Nuclear Interference (CNI) region. Carbon target Recoil carbon Ultra thin Carbon ribbon Target (5 mg/cm2) 18cm Si strip detectors (TOF, EC)

  32. The target ladder. Carbon ribbon ~5-10 um wide 25 nm thicknes

  33. April 18, 2011, Blue1, H6

  34. Pol. Profile: 250 GeV in Run-2009 Intensity and polarization profiles: R=0.280.07

  35. P-Carbon polarimeter upgrade for Run-2009 • Two polarimeters in each ring. • Routine polarization profile measurements in both-vertical and horizontal planes. • Beam intensity profile (emittance) measurements. • Doubled number of Carbon-strip targets. • New detectors development.

  36. Pol. Profile: 250 GeV in Run-2009 • Polarization loss from intrinsic resonances: polarization lost at edge of beam → polarization profile. • Impact of polarization profile on beam polarization at collisions: For RH ≈ RV and small: P0 = <P> (1+<R>)2; Pcoll. = <P> (1+½<R>) There is a

  37. Polarization evolution in AGS and RHIC. Note that P0, the polarization of the core particle, should be equal to the maximum achievable polarization. There is a possibility of an additional longitudinal polarization profile.

  38. Polarization profiles Run 9, Injection

  39. Polarization profiles at 100GeV, Run 2009

  40. Polarization profiles at 250GeV, Run 2009

  41. Run-2009, polarization profiles.

  42. Polarization profiles at injection, Run-2011 A. Poblaguev Spin Meeting

  43. 24 GeV, Blue-2, Horiz profiles, Run-2011 A. Poblaguev Spin Meeting

  44. 24 Gev, Blue-1, Horiz target, Vert profiles A. Poblaguev Spin Meeting

  45. Run-2011, 250 GeV, Blue-2, Horiz profiles A. Poblaguev Spin Meeting

  46. Run-2011,250 GeV, Yellow-1, Vert.profiles A. Poblaguev Spin Meeting

  47. Polarizaion profiles in Run-2011 A. Poblaguev Spin Meeting

  48. Polarization decay during the store.Yellow ring, Vert.target, 0.72+/-0.18%/hr

  49. Blue-1, 250 GeV, Run-2011

  50. Blue-2,Vertical target, 250 GeV

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