Beam profile measurements and transverse phase-space reconstruction on the relativistic heavy-ion collider

Abstract

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab was commissioned during the summer of 1999. Transverse beam profiles on RHIC are measured with ionization profile monitors (IPMs). An IPM measures beam profiles by collecting the electrons liberated by residual gas ionization by the beam. The detector is placed in the gap of a dipole magnet to force the electrons to travel in straight lines from the beamline center to the collector. One IPM was tested and it measured the profiles of a single gold bunch containing 10 8 ions on consecutive turns. We show an example of one of these profiles giving transverse emittance. Several profiles are assembled into a mountain-range plot which shows betatron oscillations at injection. Finally, we use tomographic techniques to reconstruct the beam transverse phase space at two times in the early beam store.