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.

线性气体塞广泛用于将高能，稀有同位素束和反应产物转换为横向发射率和能量分布较小的低能束。通过与通常会产生大量He的缓冲气体（通常是氦气）相互作用来实现高能离子的阻止${}^{+}$/ e${}^{-}$对。先进的低温气体塞子（ACGS）设计用于快速，有效地阻止和提取高强度稀有同位素束。作为设计过程的一部分，开发了一个全面的单元内粒子代码，以优化存在空间电荷（包括氦）的情况下从ACGS转运和提取稀有同位素的能力。${}^{+}$/ e${}^{-}$动力学，缓冲气体的相互作用，包括气流，射频地毯和通过喷嘴或孔口的离子提取。将提供模拟的详细信息，并在可用时与实验进行比较。