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arXiv · 2106.11139

A simulation study of a windowless gas stripping room in an E//B neutral particle analyzer

Yuan Luo·Wei-Ping Lin·Pei-Pei Ren·Guo-Feng Qu·Jing-Jun Zhu·Xing-Quan Liu·Xiao-Bing Luo·Zhu An·Roy Wada·Lin-Ge Zang·Yu-Fan Qu·Zhong-Bing Shi
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Abstract

Neutral Particle Analyzer (NPA) is one of the crucial diagnostic devices on Tokamak facilities. Stripping unit is one of the main parts of the NPA. A windowless gas stripping room with two differential pipes is adopted in a parallel direction of electric and magnetic fields (E//B) NPA. The pressure distributions in the stripping chamber are simulated by Ansys Fluent together with MolFlow+. Based on the pressure distributions extracted from the simulation, the stripping efficiency of the E//B NPA is studied with GEANT4. The hadron reaction physics is modified to track the charge state of each particle in a cross section base method in GEANT4. The transmission rates ($R$) and the stripping efficiencies $f_{+1}$ are examined for the particle energy ranging from 20 to 200 keV at the input pressure ($P_0$) ranging from 20 to 400 Pa. According to the combined global efficiency, $R \times f_{+1}$, $P_0$ = 240 Pa is obtained as the optimum pressure for the maximum global efficiency in the incident energy range investigated.

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Yuan Luo, Wei-Ping Lin, Pei-Pei Ren, Guo-Feng Qu, Jing-Jun Zhu, Xing-Quan Liu, Xiao-Bing Luo, Zhu An, Roy Wada, Lin-Ge Zang, Yu-Fan Qu, Zhong-Bing Shi. 2021-06-21. A simulation study of a windowless gas stripping room in an E//B neutral particle analyzer. https://arxiv.org/abs/2106.11139

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