RHIC Polarimetery

A.Bazilevsky for RHIC Polarimetry group

RHIC Spin Collaboration MettingApril 10 (Friday), 2009

pC measurements

Fills 10300 (Mar6) – 10522 (Apr 9)

Pol-1 measure systematically lower than Pol-2

Blue1/Blue2 1 from Fill 10476

Yell1/Yell2 1 from Fill 10505

Online Polarization (%), not normalized (!) vs fill

Rate history

Runs in reasonable conditions (below 3 MHz)

Blue-1: since fill 10476

Blue-2 : Ok

Yellow-1: since fill 10505

Yellow2: since fill 10414

pC-Blue vs HJet

Hjet/pC is stable over fills within (large) stat. errors (of HJet)

HJet: <P>=32%(fills 10402-10508)

HJet/Blue1 0.960.04(before target change, fill10476)

HJet/Blue1 0.840.04(after target change , fill10476)

HJet/Blue2 0.820.02

pC-Yellow vs HJet

Hjet/pC is stable over fills within (large) stat. errors (of HJet)

HJet: <P>=36%(fills 10439-10508)

HJet/Yell1 1.020.03(before target change, fill10505)

HJet/Yell1 HJet/Yell2(after target change , fill10505)

HJet/Yell2 0.840.03

Another APEX exercise: Polarization, “rate” corrected

Fill 10508Energy correction assumed to be an offset (baseline shift) – should be confirmed

If so, it may explain the “rate” effect (target dependence and pol1/pol2 difference)

Plans: Put pulses in other bunches (now only in bunch0)Vary pulse amplitude

After correctionBefore correction

2/NDF=12/92/NDF=24/9

Very thick targets (very high rate, >5MHz)

Backups

pC Monitoring

Generator pulses

Carbon

Ekin

ToF

pC monitoringLow rate example: 10429.013 High rate example: 10346.007

Pulse ToF vs time

Event rate vs time

Pulse rate vs time

Pulse amplitude vs time

AN vs energy

Ebeam = 100 GeVEbeam = 100 GeV

Any shift in energy measurements lead to a shift in AN (asymmetry)

FastOffline vs Online From Xuan Li

FastOffline: Use “deadlayer” concept to correct energy: all energy shifts are attributed to change in Si DeadLayer

Offline: Yell1/Yell20.9

Online: Yell1/Yell20.8

Corrects about half of “rate effect”

Flattop

FastOffline vs Online From Xuan Li

FastOffline: Use “deadlayer” concept to correct energy: all energy shifts are attributed to change in Si DeadLayer

Corrects about half of “rate effect”

Offline: Yell1/Yell20.96

Online: Yell1/Yell20.89

Injection

FastOffline vs Online From Xuan Li

FastOffline: Use “deadlayer” concept to correct energy: all energy shifts are attributed to change in Si DeadLayer

Flattop

Offline: Blue1/Blue20.88

Online: Blue1/Blue20.86

FastOffline vs OnlineInjection

FastOffline: Use “deadlayer” concept to correct energy: all energy shifts are attributed to change in Si DeadLayer

Offline: Blue1/Blue20.93

Online: Blue1/Blue20.93