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 1

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

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

4. Projected Sensitivity at PHENIX (500GeV pp) 4 ALAL ++ ++ -- --

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

6. 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 St#1 St#2 St#3 MuTr MuID

7. Need Momentum Selectivity in the LVL-1 Trigger 7 Trigger Rate and Rejection Design Luminosity √s = 500 GeV σ=60mb L = 1.6 x10 32 /cm 2 /s Total X-sec rate ＝ 9.6 MHz MuID LL1 RF=200 ~ 500 DAQ LIMIT =1-2 kHz （ for μ arm ） Required RF 10,000 BUT W signal PYTHIA

8. Parallel session (Xiaochun He) 8 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. RPC3 RPC1

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

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

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

12. 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 RPC prototype St.3 St.2 St.1 Collision point 35 cm absorber

13. The PHENIX detector 13 PHENIX 2008 shutdown

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

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

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

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

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

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

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

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

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 22 RHIC Beam Bunch counter Events Signal from chamber was recorded by new trigger system! Test pulse signal at chamber

23. Data merging : ADTX  MRG 23 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. To LL1 To DCM Strip hit data from ADTX Strip hit data from ADTX

24. Summary PHENIX muon arm is being upgraded to measure the A L 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. 24