Performance of PHENIX High Momentum Muon Trigger

Muon Tracker Octant number

4 MuTR FEE Upgrade Readout Analog Signal to Get the Position of Particle Passage (OFFLINE Analysis) Get Digital Signal for Trigger Decision (ONLINE) Readout Analog Signal to Get the Position of Particle Passage (OFFLINE Analysis) To trigger Logic ADC 0.95Q 0.05Q Q 1.Charge Sharing with multilple strips provides ~200um resolution out of 5mm strips 2.Fast readout electronics process signal fast enough before trigger decision is made Bottom Line ~10  s

5 High Momentum Muon Trigger System MuTRG ADTX MuTRG MRG Level 1 Trigger Board MuTr FEE Resistive Plate Counter (RPC) (Φ segmented) B 2 planes 5% 95% Trigger Interaction Region Rack Room Optical 1.2Gbps Amp/Discri. Transmit Data Merge MuTRG RPC FEE Trigger events with straight track (e.g.  strip <= 1) RPC / MuTRG data are also recorded on disk. SG1 DCM

Threshold Scan Run #ThresholdS.SG1N.SG mV11kHz750Hz mV76kHz18kHz mV20kHz8kHz mV15kHz32Hz mV200Hz1Hz mV20kHz1Hz mV2kHz1Hz mV1.7kHz0.5Hz mV14Hz0.4Hz mV3.8kHz1.0Hz Good correlation between threshold and N.SG1. 1Hz is reasonable true cosmic rate. Poor correlation between threshold and S.SG1. Not rates are not reproducible. 6

North Threshold Scan

All Octants (Thr=40mV) Measurement and study by SeYoung and Dahee SG １ South Trigger Rate Expected trigger rate for cosmic ~1Hz]

Masking Octant-1 (Thr=40mV) Study by Dahee and SeYoung 20min

Oct-1 Effect

Observation So Far 1. Octant-1 which has intrinsic eigenvalue of – This high rate quenches completely by masking octant-1. Masking at LL1 or MRG doesn't matter. 2.Rate excursion up to >10kHz with minutes of lifetime originated Octant-3. Excursion repeats during the run.

Threshold Response of SG1.S Rate NORTH SG1 SOUTH SG1 w/o Oct-3

MRG LL1 GL1 Oct-3 Excursion yes ADTX Oct-1 HighRate yes MRG LL1 GL1 no ADTX no ✖ mask MRG LL1 GL1 no ADTX ✖ mask Logic Test yes no yes no MRG LL1 GL1 no ADTX ✖ High Threshold yes no 10-13min no yes ~60min no

Octant-3 High Rate Time Structure

PHYSICS INTRODUCTION AND MUON TRIGGER SYSTEM

sqrt(s)=500 RHIC  Parity Violation Asymmetry Clean flavor separation w/o fragmentation uncertainty

17 High Momentum Muon Trigger Run GeV Projection New Trigger Upgrade MuID Trigger Rate 9 MHz 90 kHz σ tot =60mb L=1.5x10 32 cm -2 s -1 BBC  MuID Rejection Power RP~100 Trigger Upgrade RP ~ 45 2 kHz PHENIX Band Width for Muon Required Rejection Power RP tot ~ High Rejection Power 2.High Efficiency 1.High Rejection Power 2.High Efficiency W

18 New MuTRIG-FEE in North Arm  Before Install 2008 Install 

Diagnosis 19 Threshold scan. ✔ Angular distribution of cosmic ✔ Antimask all octants ✔ Fiber swap btwn MRG&LL1