A fast response time gas ionization chamber detector with a grid structure

Article type: Research Article

Authors: Chang, Jiahao^{a; b} | Zhu, Chaoyang^{a; b} | Song, Yuanpeng^{a; b} | Wang, Zhentao^{a; b; *}

Affiliations: [a] Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, China | [b] Beijing Key Laboratory of Nuclear Detection Technology, Beijing, China

Correspondence: [*] Corresponding author: Zhentao Wang, E-mail: wangzt@mail.tsinghua.edu.cn.

Abstract: The time response characteristic of the detector is crucial in radiation imaging systems. Unfortunately, existing parallel plate ionization chamber detectors have a slow response time, which leads to blurry radiation images. To enhance imaging quality, the electrode structure of the detector must be modified to reduce the response time. This paper proposes a gas detector with a grid structure that has a fast response time. In this study, the detector electrostatic field was calculated using COMSOL, while Garfield++ was utilized to simulate the detector’s output signal. To validate the accuracy of simulation results, the experimental ionization chamber was tested on the experimental platform. The results revealed that the average electric field intensity in the induced region of the grid detector was increased by at least 33%. The detector response time was reduced to 27% –38% of that of the parallel plate detector, while the sensitivity of the detector was only reduced by 10%. Therefore, incorporating a grid structure within the parallel plate detector can significantly improve the time response characteristics of the gas detector, providing an insight for future detector enhancements.

Keywords: Time response characteristics, gas ionization chamber, garfield++, grid detector, detector sensitivity

DOI: 10.3233/XST-230219

Journal: Journal of X-Ray Science and Technology, vol. 32, no. 2, pp. 339-354, 2024