CSNS/RCS粒子散射束流损失研究

在中国散裂中子源快循环同步加速器（CSNS/RCS）中，质子束流在加速过程中会与一些器件（如剥离膜、准直器、散射引出膜等）相互作用，产生粒子散射并导致束流损失。本工作首先利用ORBIT模拟RCS束流注入过程，并用FLUKA模拟注入束流穿过剥离膜的粒子散射过程，计算剥离膜散射所造成的束流损失。其次，模拟质子束流与准直器相互作用的粒子散射，计算质子束流与不同尺寸的次级准直器相互作用的吸收效率，作为对次级准直器优化的依据。最后，研究CSNS/RCS膜散射引出方案，利用FLUKA对不同引出方案进行模拟并比较，得到最佳的可行性方案。

Study of Beam Loss due to Particle Scattering in CSNS/RCS

In the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS), the proton beam will interact with some devices, such as the stripping foil, beam collimator, and foil for scattering extraction. These interactions result in some particle scattering and beam losses. In this paper, firstly, the beam transportation in the injection procedure was simulated by ORBIT and the particle scattering due to the interaction between the beam and stripping foil was simulated by FLUKA, then the beam loss due to the foil scattering was calculated. Secondly, the particle scattering due to the proton beam interacting with the secondary collimator was simulated, and based on which, the secondary collimator was optimized by calculating the absorb efficiency. The optimization was done for the foil scattering extraction scheme by simulating and comparing different schemes with FLUKA.