PHENIX Status, 2/22/11 VTX commissioning on beam Local polarimeter in service 9.6% in blue, -16.6% Residual transverse component for longitudinal beam If the values are true, difficult to accept MuTrig and RPC commissioning MuTrig in final adjustment Making coincidence of MuTrig and RPC Finalizing timing and trigger setup for physics running Background This morning, we saw the smooth transition on background when steering beam Still RPC background should be reduced. Working around. Collimator test, etc. Takao Sakaguchi

Integrated events Events in data files named “PHYSICS”

RPC Background investigation Hit Rates Tunnel Scalers vs RPC Rates - RHIC store Yellow beam dumped, only blue beam left in ring- (blue runs from south to north through PHENIX IR) Run Yellow beam dumped Injection Yellow beam dumped Orbit correction test Run /11 Run

Hit Rates Tunnel Scalers vs RPC Rates 480k clock trigger events. run Blue beam only RPC3S RPC3N 4/11 We see large background From Blue beam

Hit Rates Tunnel Scalers vs RPC Rates clock trigger events. Before yellow dump, both beams are on run We see large background From Both beam Note, Vertical scale is different from the previous.

Hit Rates Tunnel Scalers vs RPC Rates - Same run as before, but extracted collision-related timing. run RPC3S RPC3N 6/11 Even for collision events, We see background in center region

-location of tunnel scalers south RPC3 South South Muon arm structure 7/11

Special runs next couple days Vernier scans – With collimator test (set back after collimation) – Collimator may have caused additional background 1x3 bunch run – For RPC1 development 20% magnetic field runs

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Hit Rates Tunnel Scalers vs RPC Rates - Cosmics. run k clock trigger events. run Cosmics no beam RPC3S RPC3N 10/11