rhic polarimetery
DESCRIPTION
RHIC Polarimetery. A.Bazilevsky for RHIC Polarimetry group RHIC Spin Collaboration Metting May 1 (Friday), 2009. pC: s=2 00 GeV run. The same setup as in the end of s=500 GeV run Energy Calibration Energy and ToF corrections Targets The same measurement strategy - PowerPoint PPT PresentationTRANSCRIPT
RHIC Polarimetery
A.Bazilevsky for RHIC Polarimetry group
RHIC Spin Collaboration MettingMay 1 (Friday), 2009
pC: s=200 GeV run
The same setup as in the end of s=500 GeV runEnergy CalibrationEnergy and ToF correctionsTargets
The same measurement strategyRun all 4 polarimeters simultaneously (vertical and horizontal scans for each beam) Monitor the system (excluding detectors) during measurements with generator pulses
So far no major issues
pC Rate historys=200 GeV
Smooth, no change
pC measurements
Fills 10616 (Apr 18) – 10682 (Apr 30)
“Online” polarizations: 0.50-0.60
“Quite” consistent (relative) behavior of Pol-1 vs Pol-2
Pol-1 measure slightly lower than Pol-2: by ~5%
Online Polarization (%), not normalized (!) vs fill
pC-Blue vs HJet
Hjet/pC is stable over fills within (large) stat. errors (of HJet)
HJet: <P>=54%(fills 10616-10668)
HJet/Blue1 1.03
HJet/Blue2 0.97
pC-Yellow vs HJet
Hjet/pC is stable over fills within (large) stat. errors (of HJet)
HJet: <P>=56%(fills 10616-10646)
HJet/Yell1 1.05
HJet/Yell2 1.01
More precise Hjet-pC comparison
Hjet: fills combined in 3 periods
Drop in polarization confirmed by Hjet in both blue and yellow
pC-yellowHJet
pC-blueHJet
Pol. Profile 2
2
P
IR
Polarimeters 2Polarimeters 1
Usual…R0.15 in previous years (100 GeV beams)R0.1 Experiments see 5% more polarization than Hjet
Horizontal profile
Vertical profile
Vertical profile
Horizontal profile
Spin Horizontal Components=200 GeV
Horiz. Component:
0.065 (of ~0.55) ~7 degrees
0.035 (of ~0.55) ~3.5 degrees
Consistent between Pol-1 and Pol-2
Spin Horizontal Components=500 GeV
No spin horizontal component with 250 GeV beams
Backups
Rate historys=500 GeV
C Mass
pC: Polarization Profile
pC Scan C target over the beam cross:
Target Position
Inte
nsity
Pola
rizati
on
2
2
P
IR
I
P
2. Obtain R directly from the P(I) fit:
2
2
max 2exp)(
P
xPxP
2
2
max 2exp)(
I
xIxI
R
L
LPP
maxmax
P
I
Precise target positioning is NOT necessary
1. Directly measure I and P :
R=0.290.07
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)