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

TitleParticle-in-cell techniques for the study of space charge effects in the Advanced Cryogenic Gas Stopper
Publication TypeJournal Article
Year of Publication2021
AuthorsRingle, R, Bollen, G, Lund, K, Nicoloff, C, Schwarz, S, Sumithrarachchi, CS, Villari, ACC
JournalNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Volume496
Pagination61-70
ISSN0168-583X
KeywordsGas stopper, Particle-in-cell method, Space charge
Abstract

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

URLhttps://www.sciencedirect.com/science/article/pii/S0168583X21001117
DOI10.1016/j.nimb.2021.03.020