Particle-in-cell techniques for the study of space charge effects in the Advanced Cryogenic Gas Stopper

Linear gas stoppers are widely used to convert high-energy, rare-isotope beams and reaction products into low-energy with small transverse emittance energy spread. Stopping of the high-energy ions is achieved through interaction a buffer gas, typically helium, generating large quantities He$^+$/e$^-$ pairs. The Advanced Cryogenic Gas Stopper (ACGS) was designed for fast, efficient stopping extraction high-intensity, beams. As part design process, comprehensive particle-in-cell code developed optimize transport rare isotopes from ACGS in presence space charge, including dynamics, interactions flow, RF carpets, ion nozzle or orifice. Details simulations presented together comparison experiment when available.