A luminosity model of RHIC gold runs

Abstract

In this note, we present a luminosity model for RHIC gold runs. The model is applied to the physics fills in 2007 run without cooling, and with the longitudinal cooling applied to one beam only. Having good comparison, the model is used to project a fill with the longitudinal cooling applied to both beams. Further development and possible applications of the model are discussed.

RHIC Au beam in Run 2014

“…In general, below the transition energy, which is approximately at γ of 26.4 for IBS suppression lattice and 23.4 for the nominal lattice, the IBS model in [1] is over estimated, and at higher energy, the model is under estimated.…”

“…The observed Au bunch length and the calculated longitudinal emittance are studied for run 2011, run 2012, and run 2014, where the longitudinal emittance growth in ramp is dominated by the IBS (intra-beam scattering). A model of IBS effect on RHIC Au beams is shown in [1]. Since the longitudinal emittance growth also depends on other beam parameters, such as the transverse emittance and momentum spread, the IBS studies also provide estimate of these parameters, which are more difficult in direct measurement.…”

“…In this study, a slightly modified IBS model from the one used in [1] is applied. The IBS rise time is calibrated according to RHIC Au runs at 9.8 GeV/n, 13.5 GeV/n, 19.5 GeV/n, 31.5 GeV/n, and 100 GeV/n.…”

“…In Figure 4, the observed FWHM bunch length in 30 minutes with RHIC runs in different energy is presented. The IBS model of [1] is applied, which only has a dependence on the usual Lorentz parameters. A systematic deviation of the simulated bunch length growth from the observed ones is shown in RHIC experiments.…”

EBIS Au Beam at RHIC

“…where the first part of the equation can be found in [1]. In the second part, the bunch intensity N bh , the normalized transverse emittance N , and the longitudinal emittance are singled out for the effect of the longitudinal growth rate.…”