1 / 37

Acceleration of the polarized proton beam in the AGS with multiple partial Siberian snakes

Acceleration of the polarized proton beam in the AGS with multiple partial Siberian snakes. Junpei Takano. 1. Spin Physics. We have “the proton spin crisis”. Proton spin is not equal to “two up quarks” + “down quark”. The proton spin depends on the gluon??. up quark. gluon. Proton spin.

gaye
Download Presentation

Acceleration of the polarized proton beam in the AGS with multiple partial Siberian snakes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Acceleration of the polarized proton beam in the AGS with multiple partial Siberian snakes Junpei Takano

  2. 1. Spin Physics We have “the proton spin crisis”. Proton spin is not equal to “two up quarks” + “down quark”. The proton spin depends on the gluon?? up quark gluon Proton spin down quark

  3. 1. Spin Physics BNL has the polarized proton accelerator complex. RBRC researches the polarization of the gluon from this high energy polarized protons collision.

  4. 2. Acceleration of polarized proton beam Absolute Polarimeter (H jet) RHIC pC Polarimeters Siberian Snakes BRAHMS & PP2PP (p) RHIC PHENIX (p) STAR (p) Siberian Snakes Spin Rotators Solenoid Snake LINAC BOOSTER Pol. Proton Source 500 mA, 300 ms AGS Warm Snake 200 MeV Polarimeter AC Dipole AGS pC CNI Polarimeter Cold Snake

  5. 2. Acceleration of polarized proton beam LINAC BOOSTER Pol. Proton Source 500 mA, 300 ms 200 MeV Polarimeter No depolarization in this sections 80% polarized proton is provided

  6. 2. Acceleration of polarized proton beam Absolute Polarimeter (H jet) RHIC pC Polarimeters Siberian Snakes BRAHMS & PP2PP (p) RHIC PHENIX (p) STAR (p) Siberian Snakes Spin Rotators All depolarizing resonances are overcome by Full (100%) Siberian Snakes

  7. 2. Acceleration of polarized proton beam AGS Partial Snakes Solenoid Snake (5%) AGS Warm Snake (1.5T, 5.89%) AC Dipole AGS pC CNI Polarimeter AGS has imperfection res. and intrinsic res. Cold Snake (1.5~2.5T, 5~15%)

  8. 3. Siberian Snake for overcoming depol. res. Imperfection res. νs (spin tune) = Gγ = integer where G = (g-2)/2 = 1.7928 in the proton case Weak partial snake is enough to overcome before 2004: solenoid snake → Coupling res. after 2004: warm snake Intrinsic res. νs = Gγ = kP±νy where k is integer, P is super periods (P=12 for AGS), νy is vertical tune (~8.95 in AGS) by using AC dipole or strong partial snake cold snake was installed in 2005 Coupling res. νs = Gγ = kP±νx (νx=8.6 in AGS)

  9. 2. Acceleration of polarized proton beam Warm Snake

  10. 2. Acceleration of polarized proton beam Cold Snake

  11. 3. Siberian Snake for overcoming depol. res. Formula of spin tune and Siberian snake strength cosπνs＝cos(δ/2) cosπGγ where δ is the angle which snake can tilt

  12. 3. Siberian Snake for overcoming depol. res. Snake strength of the AGS partial Siberian snakes Injection Extraction Snake strength depends on the beam energy.

  13. 3. Siberian Snake for overcoming depol. res. 12+v 36-v 24+v 48-v 36+v RUN4 -7.2% +1.5% +4.6% -0.5% -8.2% RUN3 N/A -13.4% -6.9% -8.3% -17.5%

  14. 3. Siberian Snake for overcoming depol. res. Results of RUN4 Total asymmetry drop at the intrinsic res. In RUN4 = -1.6% Total asymmetry drop at the intrinsic res. In RUN3 = -46.1% Polarization at the AGS flat top in RUN3 = 40% Polarization at the AGS flat top in RUN4 = 50% The warm snake increases the polarization 25%

  15. 4. Double partial snakes scheme Locations of the snakes in the AGS Warm Snake at E20 Cold Snake at A20 1/3 of the ring Merit 1: making the spin tune gap bigger at the intrinsic resonances Merit 2: decreasing the spin mismatch at the injection and extraction

  16. 4. Double partial snakes scheme Large spin tune gap Gγ= 3k k: integer Intrinsic res. νs = Gγ= 12k±νy Large spin tune gap 48-νy 36+νy WSNK=6% CSNK=10% Extraction energy

  17. 4. Double partial snakes scheme Spin tune around injection energy and first intrinsic resonance Large spin tune gap 0+νy WSNK=8.4% CSNK=16% Injection energy

  18. 4. Double partial snakes scheme WSNK = 8.4% Injection energy Spin mismatch Vertical component at L20 = 0.991

  19. 4. Double partial snakes scheme WSNK = 6% Extraction energy Spin mismatch Vertical component at H10 = 0.996

  20. 4. Double partial snakes scheme CSNK = 16% Injection energy Spin mismatch Vertical component at L20 = 0.969

  21. 4. Double partial snakes scheme CSNK = 10% Extraction energy Spin mismatch Vertical component at H10 = 0.988

  22. 4. Double partial snakes scheme CSNK = 16%, WSNK = 8.4% Injection energy Spin mismatch Vertical component at L20 = 0.992

  23. 4. Double partial snakes scheme CSNK = 10%, WSNK = 6% Extraction energy Spin mismatch Vertical component at H10 = 0.998

  24. 4. Double partial snakes scheme WSNK only: small spin mismatch CSNK only: spin mismatch comes worse WSNK + CSNK: small spin mismatch Stronger CSNK makes spin mismatch bigger.

  25. 5. Results of RUN5 Asymmetry at Gγ=4.5 (Injection energy) Calculated curve Spin mismatch were measured at injection energy

  26. 5. Results of RUN5 0+v 12+v Effect of AC dipole

  27. 5. Results of RUN5 36-v Effect of AC dipole 36+v

  28. 5. Results of RUN5 All intrinsic resonances are overcome by the Cold Snake without AC dipole

  29. 5. Results of RUN5 Polarization in RHIC 100GeV vs. 100GeV

  30. 6. Three partial snakes scheme If the Solenoid Snake is moved from I10 to I20.... Solenoid Snake (I10) AGS Warm Snake (E20) Cold Snake (A20)

  31. 6. Three partial snakes scheme CSNK = 16%, WSNK = 8.4%, SSNK = -7.6% Injection energy No spin mismatch

  32. 6. Three partial snakes scheme CSNK = 10%, WSNK = 6%, SSNK = 4% Extraction energy No spin mismatch

  33. 6. Three partial snakes scheme 10% extraction 4% ramp up SSNK strength % 0% -7.6% injection The current at injection is negative for no spin mismatch. Then the current should be turned to positive for making spin tune large, but the bipolar PS is needed in this case.

  34. 6. Three partial snakes scheme Large spin tune gap CSNK=16% WSNK=8.4% SSNK= 10% Injection energy

  35. 6. Three partial snakes scheme Large spin tune gap CSNK=10% WSNK=6% SSNK= 4% Extraction energy

  36. 7. Summary Warm Snake has been installed in RUN4 Polarization was improved to 50% at extraction of AGS Cold Snake has been installed in RUN5 2snakes scheme had been worked All intrinsic resonances are overcome by Cold Snake Spin mismatch at injection was measured 3snakes scheme for no spin mismatch was calculated 3snakes scheme can help the spin tune gap larger

  37. Special thanks • L. Ahrens, M. Bai, E. D. Courant, J. W. Glenn, H. Huang, F. Lin, • U. Luccio, W. W. MacKay, T. Roser, N. Tsoupas, J. Woods • and all members in Main Control Room in BNL • M. Okamura / RIKEN • T. Hattori / TITECH

More Related