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PHENIX local polarimeter @ RUN9

PHENIX local polarimeter @ RUN9. 2009/02/27 @ RSC meeting. Took data @ Fill#10228. 56*56 bunch collision Polarization @ CNI monitor : 20-30% Sample selection Collected by BBCLL1&(ZDCN|S) Measured energy @ ZDC > 40 GeV. SMD hit at least 2 columns to determine the position.

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PHENIX local polarimeter @ RUN9

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  1. PHENIX local polarimeter@ RUN9 2009/02/27 @ RSC meeting

  2. Took data @ Fill#10228 • 56*56 bunch collision • Polarization @ CNI monitor : 20-30% • Sample selection • Collected by BBCLL1&(ZDCN|S) • Measured energy @ ZDC > 40 GeV. • SMD hit at least 2 columns to determine the position. Cut parameters are very preliminary

  3. First results from RUN9(First measurement at 500 GeV!) Blue forward Yellow forward BBCLL1&(ZDCN|S) ~20 M evts By sqrt formula Blue backward Yellow backward

  4. New! Local pol. scalers Make scaler in ZDC LL1 bord 4*2*120 channels 20 bits in each! Make hit pattern by TDC in FEM (with high threshold) • We can measure spin condition bunch-by-bunch • We can measure it online. • So far we took LP trigger with 200 Hz at physics run, and analyze it after run. SMD scintillators for y (8 scinti.) ZDC LL1 TOP Hit patterns are sent by fibers Bottom SMD scintillators for x (7 scnti.) Local pol. scaler is developing by : Cheng-Yi Chi, Ed Desmond, Yuji Goto, John Haggerty, John Lajoie and Manabu Togawa LEFT RIGHT

  5. Scaler counts - 10 mins data - SMD threshold has no optimization. Just apply high threshold for this data. - Small BG can be confirmed by unfilled bunch

  6. LP scaler can see asymmetry too! Measured @ SOUTH LR Measured @ NORTH LR Fill#10228 (NL-NR)/(NL+NR) Measured @ SOUTH TB Measured @ NORTH TB (NB-NT)/(NB+NT) Crossing# Significant asymmetry in LR only and we got it bunch-by-bunch! This is just 10 minutes data. We need to check stability.

  7. 2009/02/27 (28*28 bunch collision) Measured @ SOUTH LR Measured @ NORTH LR Fill#10260 (NL-NR)/(NL+NR) Measured @ SOUTH TB Measured @ NORTH TB (NB-NT)/(NB+NT) Crossing#

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  9. SMD 1 ZDC ZDC (Zero Degree Calorimeter) Setup Schematic view from simulation. - GEANT3 (Geisha) - From the pythia simulation, Main backgrounds are photon and proton. 10*10cm  ±2.8 mrad 3 module 150X0 5.1λI Collision point 1800 cm SMD (Shower Max Detector) BBC Neutron position can be decided by centroid method.

  10. Detector asymmetry Blue forward Yellow forward Raw asymmetry Luminosity asymmetry ~ 0.5-1.5% f Blue backward Yellow backward Detector asymmetries are up to 50%, but it is cancelled according to backward asymmetry.

  11. ZDC energy distribution with high threshold cut for SMD (in ZDCN|S sample @ RUN5 data) NORTH SOUTH • SMD threshold corresponds to 20 MIP • With high SMD cut can be help to select neutron sample. • BG1 : photon will stop at 1st module; not hit SMD. • BG2 : proton event is only distributed low energy region. Bottom cut Top cut Bottom cut Top cut Left cut Right cut Left cut Right cut 70 GeV Measured energy in ZDC (GeV)

  12. Raw asymmetry for Fill#10228 Measured @ SOUTH LR Measured @ NORTH LR (NL-NR)/(NL+NR) Measured @ SOUTH TB Measured @ NORTH TB (NB-NT)/(NB+NT) Crossing#

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