Absolute polarimetry at RHIC

Abstract

Abstract. Precise and absolute beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of A&am/Pbeam < 5%.The absolute polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip detectors and was installed in the RHIC-ring in 2004. This system features proton-proton elastic scattering in the Coulomb nuclear interference (CNI) region. Precise measurements of the analyzing power AN of this process has allowed us to achieve Mbeam/Pbeam = 4.2% in 2005 for the first long spin-physics run.In this report, we describe the entire set up and performance of the system. The procedure of beam polarization measurement and analysis results from 2004 -2005 are described. Physics topics of AN in the CNI region (four-momentum transfer squared 0.001 < -t < 0.032 (GeV/c)2) are also discussed. We point out the current issues and expected optimum accuracy in 2006 and the future.

Polarized negative ion source with multiply spherically focusing surface plasma ionizer

“…The BNL polarized atomic H jet [ 11 ] has an intensity of up to 1.7 10 17 atoms/s and polarization of ~0.97 in the DC mode of operation and it is possible to have an even higher intensity and polarization in the pulsed mode of operation. An ABS with very good parameters was developed for the internal target experiments at BINP [ 12 ].…”

Perspective for development of a universal source of highly polarized ions

“…These developments can use to improve an ABPIS design. a b Figure 6: a) Schematic of the BNL ABPS [14]; the H-jet polarimeter includes three major parts: polarized Atomic Beam Source (ABS), scattering chamber, and Breit-Rabi polarimeter. The polarimeter axis is vertical and the recoil protons are detected in the horizontal plane.…”

Measuring transverse beam emittance using a 2.07 GHz movable Schottky cavity at the Relativistic Heavy Ion Collider

“…A fourth system that is currently being developed is to use a camera to measure the fluorescence induced by the passage of the beam through a hydrogen jet [8], which is primarily used to measure and calibrate the beam polarization in RHIC [9]. At present, this system is limited to measuring just the vertical beam size.…”