Proton Polarimetry at RHIC K. Oleg Eyser for the CNI polarimeter group Newport News, VA, October 25, 2013

2 2 2 AGS LINAC BOOSTER Polarized Source Spin Rotators 200 MeV Polarimeter Absolute Polarimeter (H jet) P HENIX B RAHMS & PP2PP S TAR Siberian Snakes Spin Flipper RHIC pC Polarimeters Rf Dipole AGS Internal Polarimeter AGS pC Polarimeter Strong Snake Partial Snake Helical Partial Snake

3 3 3 RHIC Luminosity Beam momentum 100 GeV 250 GeV Consistent luminosity improvement over the years 255 GeV in 2013

4 4 4 Polarization and Asymmetries S x y N P  Polarization: left right scattering plane (proton) (Carbon)

5 5 5 Polarimeters in RHIC normalization Carbon polarimetersHydrogen jet beam

6 6 6 Elastic Signal Identification ADC/TDC waveform readout normalized to peak  ADC max  TDC 0 V10BASELINE Elastic signal → Energy calibration → Time offset

7 7 7 Energy Calibration Stopping power for α-particles and protons from NIST database

8 8 8 Elastic Signal and Background 5 MeV 1 MeV signal regionbackground region atomic jet target proton beam

9 9 9 Asymmetry and Polarization Polarization independent background Polarization dependent background abort gaps

10 Polarimeter Performance Kinematic distributions for consistency checks Fast feedback to RHIC operations Target P=92% 1 Fill over 150 RHIC fills in 2013

11 Summary  Polarization in RHIC is measured with  fast p+C targets for monitoring, polarization profiles, and polarization decay,  a polarized atomic hydrogen jet for normalization.  The 2013 data provides unprecedented possibilities to use the jet polarimeter for background studies.  The jet polarimeter provides fast feedback to RHIC operations.  Final analysis and systematic studies are on-going.

BACKUP

13 Polarization Profile jet target polarization is flat vertical and horizontal Carbon targets available