BNL, Upton, Long Island, New York, USA
FRIB, East Lansing, USA
LBNL, Berkeley, California, USA
JLab, Newport News, Virginia, USA
The 2015 Nuclear Science Advisory Committee Long Rang Plan identified the need for an electron-ion collider facility as a gluon microscope with capabilities beyond those of any existing accelerator complex. To reach the required high energy, high luminosity, and high polarization, the eRHIC design based on the existing heady ion and polarized proton collider RHIC adopts a very small beta-function at the interaction point, a high collision repetition rate, and a novel hadron cooling scheme. Collision with a full crossing angle of 22 mrad and crab cavities for both electron and proton rings are required. In this article, we will present the high priority R&D items related to beam-beam interaction for the current eRHIC design, the simulation challenges, and our plans to address them.
FRIB, East Lansing, USA
The Facility for Rare Isotope Beams (FRIB) being built at Michigan State University moved to the commissioned stage in the summer of 2017. There were extensive beam dynamics simulations in the FRIB driver linac during the design stage. Recently, we have used TRACK and IMPACT simulation codes to study dynamics of ion beam contaminants extracted from the ECR together with main ion beam. The contaminant ion species can produce significant losses after the stripping. These studies resulted in development of beam collimation system at relatively low energy of 16 MeV/u and room temperature bunchers instead of originally planned SC cavities. Commissioning of the Front End and the first 3 cryomodules enabled detailed beam dynamics studies experimentally which were accompanied with the simulations using above-mentioned beam dynamics codes and optimization code FLAME. There are significant challenges in understanding of beam dynamics in the FRIB linac. The most computational challenges are in the following areas: (1) Simulation of the ion beam formation and extraction from the ECR; (2) Development of the virtual accelerator model available on-line both for optimization and multi-particle simulations. The virtual model should include realistic accelerator parameters including device misalignments; (3) Large scale simulations to support high-power ramp up of the linac with minimized beam losses; (4) Interaction of the beam with the gas stripper which is the backup option for high power operation of the linac.