PHENIX Run 11 pp Kieran Boyle PHENIX Goals

PHENIX Run 11 p+p Kieran Boyle ( )

PHENIX Goals for Run 11 • Physics: – First measurement W cross section and asymmetry – W e in central arm – 0 ALL in MPC and central arm • Commissioning of three new systems: – RPC Detector – Muon Trigger (Muon Trig FEE and RPC) – VTX Kieran Boyle – RSC – May 6, 2011 2

Timeline for Run • Jan 4 -Jan 27: Setup of PHENIX • Jan 27 -Feb 11: Commissioning of Muon trig FEE and RPC, Preparatory work for Local. Pol • Feb 11: PHYSICS declared by CAD • Feb 11 -Feb 16: Local Pol measurement, some transverse running • Feb 17 -25: Rotator commissioning (last special run 3/1), fine tuning of Muon trig Fee system • Feb 27: PHENIX declares Physics – Muon Trigger defined as MUIDLL 1&&SG 1&&BBCnotvertex – RPC taking data, but high background at start of fills • Mar 2: Additional Shielding in South tunnel • Mar 7 -Mar 16: Cryo failure – Shielding in North tunnel – Fixed drift chamber wire • Mar 17 -20: Power failure in AGS Kieran Boyle – RSC – May 6, 2011 3

Timeline for Run • Mar 23: Modified RPC gas mixture, increased RPC efficiency • Mar 30: Move tunnel scintillators, to better correlate high current with background seen by RPCs • Apr 13: 9 MHz failure • Apr 15: RPC trigger commissioning finished for Run 11, VTX always in data taking • Apr 18: p+p run ends Kieran Boyle – RSC – May 6, 2011 4

Final stats for Run • Original goal for Run 11: L=50 pb-1 with P=50% • Reduced goal after cryo failure: L=20 pb-1 • Achieved: L=16. 7 pb-1 with P=45% (online) – 1/3 of original luminosity goal, 84% of reduced goal – Final figure of merit achieved will wait for more firm P value Kieran Boyle – RSC – May 6, 2011 5

Rotator Commissioning • • • PHENIX takes dedicated special runs for rotator commissioning Start in transverse running 2/2. Longitudinal from 2/17 Commissioning required 5 iterations “Final” settings 3% and 5% transverse components – During STAR rotator commissioning, we saw our component increase according to scaler values – As was near end of run, we decided not to change Rotator off Wrong setting Kieran Boyle – RSC – May 6, 2011 Final setting: change in fill 6

RPC Commissioning • Detectors ready for data taking in February – Available for analysis. Reduces background for W. – Gas change in March increased efficiency • Most luminosity with this setting • Cautious early on with new detector system – Initially, low trip voltage setting • Difficult to turn on with high background rates (start of run, An. DY) • On for most of fill for most fills at end of Run 11 – Increased trip threshold, and better steering by CAD Kieran Boyle – RSC – May 6, 2011 7

Shielding Added in tunnels • Added near Q 3, covered in holes in previous shielding. • Shielding added to South (3/2) and North (3/10) • Working on plan for possible additional shielding in summer shutdown. Kieran Boyle – RSC – May 6, 2011 8

rejection Effect of Shielding Before shielding After shielding Collision rate • Clear increase in rejection in MUID triggers after shielding as compared to before. Other trigger, including W trigger show similar. • Reduced background in RPCs Kieran Boyle – RSC – May 6, 2011 9

Muon Trigger Commissioning • High efficiency for high momentum muon tracks • Good Rejection: – Large variation in red points from threshold scan • Muon physics trigger: SG 1&&MUIDLL 1&&BBCnovertex • Rejection was enough that trigger was never prescaled, even at highest rates in Run 11 rejection – SG 1 selects small sagita of high momentum track Before shielding After shielding – Around 5 k. Hz total rate at maximum collision rate • RPC trigger commissioned before end of pp Collision rate Kieran Boyle – RSC – May 6, 2011 10

VTX Commissioning • Most commissioning happened in parallel to data taking • Integrated in all data starting April 14 • Reasonable measurement of beam size ry a in m i l re p y r e V Single strip ladder used Kieran Boyle – RSC – May 6, 2011 11

Other Performance Plots • No clear impact from 9 MHz RF on vertex width PHENIX Runnumber • Not so many long stores in Run 11. Kieran Boyle – RSC – May 6, 2011 12

Summary • Run 11 p+p was difficult, but PHENIX did commission 3 new systems: Muon trigger, RPC (incl. trigger) and VTX. • RHIC was able to produce high intensity stores and higher pol. – Need better integrated luminosity, not only instantaneous • Need to see better machine reliability in next run • We recorded 17 pb-1 in 30 cm vertex cut, enough for a cross section for the forward W. Kieran Boyle – RSC – May 6, 2011 13