Beam lifetime and emittance growth measurements of gold beams in RHIC at storage

Abstract

During stores of gold beams, longitudinal and transverse beam sizes were recorded., Longitudinal profiles were obtained with a wall current monitor. Transverse profiles were reconstructed from gold-gold collision rates at various relative transverse beam positions. The total beam lifetime was measured with a beam current transformer, the bunched beam lifetime with the wall current monitor. Diffusion rates in the beam halo were determined from the change in the loss rate when a scraper is retracted. The measurements are used to determine the lifetime limiting effects. Beam growth measurements are compared with computation's of beam-growth times from intra-beam scattering.