BNL, Upton, Long Island, New York, USA
There has been increasing interest in low energy run in RHIC to study the QCD phase diagram and search for the critical point. The machine optics is one of the critical pieces for a successful low energy run since it affects the luminosity and its lifetime. Despite the difficulties of taking optics measurement data, progress has been made in recent years to analyze and correct the global optics errors. The analysis technique and specific exception handling, and the results of optics correction for low energy runs will be presented in the report.
BNL, Upton, Long Island, New York, USA
At RHIC, heavy ion beams cross transition energy during acceleration to energies required by the physics programs. In the past, to battle longitudinal instabilities, a Landau cavity was turned on just after acceleration through transition energy. The Landau cavity with modified frequency will be implemented before beam crosses transition in Run-14. Longitudinal dynamics with this new configuration have been simulated to optimize the phase and amplitude of the Landau cavity. We will present simulation results in the report.
BNL, Upton, Long Island, New York, USA
To search for the critical point in the QCD phase diagram, RHIC has been colliding gold ions at a variety of beam energies ranging from 2.5 GeV/n to 9.8 GeV/n. During these low energy operations below the regular injection energy, significant lifetime reductions due to the beam-beam interaction in conjunction with large space charge tune shifts have been observed. Extensive simulation studies as well as beam experiments have been performed to understand this phenomenon, leading to improved performance during the 7.3 GeV run in FY2014.
