The Energy Response of LaBr3(Ce), LaBr3(Ce,Sr) and NaI(Tl) Crystals for GECAM

Pei-Yi Feng; Xi-Lei Sun; Zheng-Hua An; Yong Deng; Cheng-Er Wang; Huang Jiang; Jun-Jie Li; Da-Li Zhang; Xin-Qiao Li; Shao-Lin Xiong; Chao Zheng; Ke Gong; Sheng Yang; Xiao-Jing Liu; Min Gao; Xiang-Yang Wen; Ya-Qing Liu; Yan-Bing Xu; Xiao-Yun Zhao; Jia-Cong Liu; Fan Zhang; Hong Lu

arXiv · 2312.16658

The Energy Response of LaBr3(Ce), LaBr3(Ce,Sr) and NaI(Tl) Crystals for GECAM

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Abstract

The GECAM series of satellites utilize LaBr3(Ce), LaBr3(Ce,Sr), and NaI(Tl) crystals as sensitive materials for gamma-ray detectors (GRDs). To investigate the non-linearity in the detection of low-energy gamma rays and address errors in the E-C relationship calibration, comprehensive tests and comparative studies of the non-linearity of these three crystals were conducted using Compton electrons, radioactive sources, and mono-energetic X-rays. The non-linearity test results for Compton electrons and X-rays displayed substantial differences, with all three crystals showing higher non-linearity for X-rays and gamma-rays than for Compton electrons. Despite LaBr3(Ce) and LaBr3(Ce,Sr) crystals having higher absolute light yields, they exhibited a noticeable non-linear decrease in light yield, especially at energies below 400 keV. The NaI(Tl) crystal demonstrated excess light output in the 6~200 keV range, reaching a maximum excess of 9.2% at 30 keV in X-ray testing and up to 15.5% at 14 keV during Compton electron testing, indicating a significant advantage in the detection of low-energy gamma rays. Furthermore, this paper explores the underlying causes of the observed non-linearity in these crystals. This study not only elucidates the detector responses of GECAM, but also marks the inaugural comprehensive investigation into the non-linearity of domestically produced lanthanum bromide and sodium iodide crystals.

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Pei-Yi Feng, Xi-Lei Sun, Zheng-Hua An, Yong Deng, Cheng-Er Wang, Huang Jiang, Jun-Jie Li, Da-Li Zhang, Xin-Qiao Li, Shao-Lin Xiong, Chao Zheng, Ke Gong, Sheng Yang, Xiao-Jing Liu, Min Gao, Xiang-Yang Wen, Ya-Qing Liu, Yan-Bing Xu, Xiao-Yun Zhao, Jia-Cong Liu, Fan Zhang, Hong Lu. 2023-12-27. The Energy Response of LaBr3(Ce), LaBr3(Ce,Sr) and NaI(Tl) Crystals for GECAM. https://arxiv.org/abs/2312.16658

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