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Oct. 10, 2008 Tsutomu Mibe (KEK) for the PHENIX collaboration

Study of polarized sea quark distributions in polarized pp collisions at sqrt(s)=500GeV with PHENIX. Oct. 10, 2008 Tsutomu Mibe (KEK) for the PHENIX collaboration. Are Sea Quarks Polarized?. A fundamental question to further break down the quark spin contents DS ~0.25

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Oct. 10, 2008 Tsutomu Mibe (KEK) for the PHENIX collaboration

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  1. Study of polarized sea quark distributions in polarized pp collisions at sqrt(s)=500GeV with PHENIX Oct. 10, 2008 Tsutomu Mibe (KEK) for the PHENIX collaboration

  2. Are Sea Quarks Polarized? • A fundamental question to further break down the quark spin contents DS ~0.25 • Flavor sensitive measurements required • Semi-inclusive • Weak interaction

  3. Flavor is almost fixed W+ Production in pp Collisions • Best suited for Spin-Flavor Structure Studies nm • Parity violating V-A interaction selects only left-handed quarks and right-handed antiquarks m+ W+ u d

  4. Projected Sensitivity at PHENIX (500GeV pp) m- m+ AL m- m+

  5. p (250 GeV) p (250 GeV) The PHENIX detector μ

  6. Current Muon System • Muon Tracking Chambers (MuTr) • 3 stations of Cathode strip chambers with 2 or 3 gaps • Cathode (1.0 cm pitch) • Non-stereo-strip • stereo-strip • Muon Identifier (MuID) • 80 cm of steel plate absorber (total) • 5 layers of Iarocci tubes in x and y directions • Provides LL1 trigger based on road-finding MuID MuTr St#1 St#2 St#3

  7. Trigger Rate and Rejection Design Luminosity √s = 500 GeV σ=60mb L = 1.6 x1032/cm2/s PYTHIA Total X-sec rate＝9.6 MHz DAQ LIMIT =1-2 kHz （for μ arm） W signal Required RF 10,000 BUT Need Momentum Selectivity in the LVL-1 Trigger MuID LL1 RF=200 ~ 500

  8. RPC1 RPC3 Trigger Algorithm • Momentum selectivity through online sagitta measurement • Uses MuTR 1,2,3 and new Resistive Plate Chambers (RPC) planes • Out-of-time BGs rejected by fast RPC signals. Parallel session (Xiaochun He)

  9. RPC B Upgraded read out system IR Counting House Level 1 Trigger Board Trigger Merge Reformat Amp/Discri. Data Collecting Module MuTRG MRG 5% MuTRG ADTX LV1 Trig accept 2 plane MuTr FEE 95%

  10. MuTr Front End Electronics (FEE) Existing readout New addition

  11. Amplifier-Discriminator board (MuTRG-ADTX) Analog signal from MuTr (64 ch) 6.5 V Dry air Regulators (3.3, 2.5, 1.2 V) Cooling Water Cooling Water 1.2 Gbps 9.4 MHz

  12. Installation plan in 2008 • South Arm • Station 1, 2, 3 (1/2 octant) • RPC prototype D (2x 1/2 octants) • Absorber prototype (1 octant) • North Arm • Station 1 (8 octants) • Station 2 (8 octants) • Station 3 (8 octants) St.3 St.2 St.1 Collision point St.1 St.2 St.3 RPC prototype 35 cm absorber

  13. PHENIX 2008 shutdown The PHENIX detector

  14. Production status of trigger electronics Ckecking power lines • Chassis (130 pcs) • Completed mass production • Completed quality checking Water pressure/leak test Backplane check

  15. Production status of trigger electronics • Chassis (130 pcs) • Completed mass production • Completed quality checking

  16. Existing FEE MuTRG-ADTX Pseudo MuTR Chamber Production status of trigger electronics Test bench at RIKEN • ADTX boards (220 pcs) • Completed production of 132 boards • Completed quality checking of 102 boards (RIKEN/KEK/BNL) Test bench at BNL

  17. Installation status North muon arm before installation Station 3 Station 2 Station 1 N Station 1

  18. Installation status Mounting chassis to station 1 Station 3 Station 2 Station 1 N Station 1

  19. Installation status Mounting chassis to st2 Mounting chassis to bottom of st1 St2 after chassis installation

  20. Installation status Boards slided into chassis at station 1 After all boards installed at station 1

  21. Installation status • Completed construction of infrastructure at North arm • Completed mounting all chassis. • Completed installing the ADTX boards to North station 1. N Station 1

  22. And its working! • Generated test pulse at chamber strip • Read out by ADTX board (100 triggers) • North Station 1 Octant 5 Gap 3 Plane 2 Strip 4 Test pulse signal at chamber Events Signal from chamber was recorded by new trigger system! RHIC Beam Bunch counter

  23. Data merging : ADTXMRG • Merging and reformatting strip data from ADTX boards • The first prototype • Successfully receive and reformat the data from multiple ADTX boards. • Initial communication tests with downstream modules (LL1 and DCM) has been done. • Next version will be produced by the end of this year. Strip hit data from ADTX To LL1 Strip hit data from ADTX To DCM

  24. Summary • PHENIX muon arm is being upgraded to measure the AL of W boson production in pp collisions at 500 GeV. • The muon trigger upgrade has been making steady progress as scheduled. • Installation to the North muon arm will be completed during this year’s shutdown.

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