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arXiv · 2604.19497

Design and preliminary performance study of the broad-band spectrometer detector for POLAR-2

Jian-Chao Sun·Jiang He·Shuang-Nan Zhang·Shao-Lin Xiong·Jiang-Tao Liu·Yan-Bing Xu·Jia Ma·Shuo Wang·Lei Shuai·Xiu-Zuo Liang·Hong-Bang Liu·Fei Xie·Ming Zeng·Philipp Azzarello·Joerg Bayer·Franck Cadoux·Nicolas De Angelis·Huan-Bo Feng·Zu-Ke Feng·Min Gao·Ramandeep Gill·Jonathan Granot·Jochen Greiner·Alejandro Guzman·Jin-Xiu Hu·Yue Huang·Johannes Hulsman·Zheng-Huo Jiang·Merlin Kole·Dao-Wu Li·Han-Cheng Li·Tong-Lei Liao·Long Peng·Agnieszka Pollo·Nicolas Produit·Dominik Rybka·Andrea Santangelo·Li-Ming Song·Chris Tenzer·Xiao-Ming Wang·Yuan-Hao Wang·Bo-Bing Wu·Pei-Lian Wu·Xin Wu·Shuo Xiao·Sheng Yang·Lai-Yu Zhang·Lei Zhang·Yong-Jie Zhang
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Abstract

POLAR-2, the successor of the POLAR experiment aboard China's Tiangong-2 space lab, is set to be deployed on the China Space Station. The POLAR-2 mission aims to conducting high-precision polarization measurements of high-energy transients with a primary focus on Gamma-Ray Bursts (GRBs), following POLAR's pioneering accurate polarization measurements of GRB prompt emission. One of the key advancements in POLAR-2 is the inclusion of a dedicated Broad-band Spectrometer Detector (BSD) instrument, designed to provide precise measurements of GRB location and spectral parameters, which are critical inputs for accurate polarization analysis of POLAR-2's dedicated High-energy Polarimetry Detector (HPD), which is made of plastic scintillator bars array. BSD employs a coded-aperture mask imaging technique and pixelated GAGG scintillation crystals, offering a wide half-coded field of view of ~132{\deg} x 125{\deg} and an operational energy range of 10-1000 keV. Simulation results indicate that the instrument can achieve a localization accuracy of approximately 1.5{\deg} for faint GRBs similar to GRB 170817A, satisfying the core requirements of GRB polarimetry with HPD. BSD also has moderate capability for GRB polarimetry, particularly at several hundred keV energy. This paper outlines the preliminary design of BSD and presents an overall evaluation of its expected scientific performance, based on extensive Monte Carlo simulations and preliminary ground-based calibration tests.

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Jian-Chao Sun, Jiang He, Shuang-Nan Zhang, Shao-Lin Xiong, Jiang-Tao Liu, Yan-Bing Xu, Jia Ma, Shuo Wang, Lei Shuai, Xiu-Zuo Liang, Hong-Bang Liu, Fei Xie, Ming Zeng, Philipp Azzarello, Joerg Bayer, Franck Cadoux, Nicolas De Angelis, Huan-Bo Feng, Zu-Ke Feng, Min Gao, Ramandeep Gill, Jonathan Granot, Jochen Greiner, Alejandro Guzman, Jin-Xiu Hu, Yue Huang, Johannes Hulsman, Zheng-Huo Jiang, Merlin Kole, Dao-Wu Li, Han-Cheng Li, Tong-Lei Liao, Long Peng, Agnieszka Pollo, Nicolas Produit, Dominik Rybka, Andrea Santangelo, Li-Ming Song, Chris Tenzer, Xiao-Ming Wang, Yuan-Hao Wang, Bo-Bing Wu, Pei-Lian Wu, Xin Wu, Shuo Xiao, Sheng Yang, Lai-Yu Zhang, Lei Zhang, Yong-Jie Zhang. 2026-04-21. Design and preliminary performance study of the broad-band spectrometer detector for POLAR-2. https://doi.org/10.1007/s10686-026-10043-1

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