Detector calibration based on secondary protons of Back-n white neutron source
Authors: Jiang Wei , Jiang Hao-Yu , Yi Han , Fan Rui-Rui , Cui Zeng-Qi , Sun Kang , Zhang Guo-Hui , Tang Jing-Yu , Sun Zhi-Jia , Ning Chang-Jun , Gao Ke-Qing , An Qi , Bai Huai-Yong , Bao Jie , Bao Yu , Cao Ping , Chen Hao-Lei , Chen Qi-Ping , Chen Yong-Hao , Chen Yu-Kai , Chen Zhen , Feng Chang-Qing , Gu Min-Hao , Han Chang-Cai , Han Zi-Jie , He Guo-Zhu , He Yong-Cheng , Hong Yang , Huang Han-Xiong , Huang Wei-Ling , Huang Xi-Ru , Ji Xiao-Lu , Ji Xu-Yang , Jiang Zhi-Jie , Jing Han-Tao , Kang Ling , Kang Ming-Tao , Li Bo , Li Chao , Li Jia-Wen , Li Lun , Li Qiang , Li Xiao , Li Yang , Liu Rong , Liu Shu-Bin , Liu Xing-Yan , Luan Guang-Yuan , Mu Qi-Li , Qi Bin-Bin , Ren Jie , Ren Zhi-Zhou , Ruan Xi-Chao , Song Zhao-Hui , Song Ying-Peng , Sun Hong , Sun Xiao-Yang , Tan Zhi-Xin , Tang Hong-Qing , Tang Xin-Yi , Tian Bin-Bin , Wang Li-Jiao , Wang Peng-Cheng , Wang Qi , Wang Tao-Feng , Wang Zhao-Hui , Wen Jie , Wen Zhong-Wei , Wu Qing-Biao , Wu Xiao-Guang , Wu Xuan , Xie Li-Kun , Yang Yi-Wei , Yu Li , Yu Tao , Yu Yong-Ji , Zhang Lin-Hao , Zhang Qi-Wei , Zhang Xian-Peng , Zhang Yu-Liang , Zhang Zhi-Yong , Zhao Yu-Bin , Zhou Lu-Ping , Zhou Zu-Ying , Zhu Dan-Yang , Zhu Ke-Jun , Zhu Peng , The CSNS Back-n Collaboration   ,   Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China,   Spallation Neutron Source Science Center, Dongguan 523803, China,   State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China,   State Key Laboratory of Particle Detection and Electronics, China,   University of Chinese Academy of Sciences, Beijing 100049, China,   Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China,   Key Laboratory of Nuclear Data, China Institute of Atomic Energy, Beijing 102413, China,   Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China,   Northwest Institute of Nuclear Technology, Xi’an 710024, China,   Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei 230026, China,   School of Physics, Beihang University, Beijing 100083, China
Published: December 2020

At present, there exist few proton-beam terminals for the detector calibration in the world. Meanwhile, most of these terminals provide monoenergetic protons. Back-n white neutron source from China Spallation Neutron Source(CSNS) was put into operation in 2018. Based on the white neutron flux ranging from 0.5 eV to 200 MeV from the CSNS Back-n white neutron source, continuous-energy protons involved in a wide energy spectrum can be acquired from the <sup>1</sup>H(n, el) reaction. Adopting this method, a new research platform for researches such as proton calibration is realized at CSNS. As hydrogen exists as gas at normal temperature and pressure, in the selecting of the proton-converting target, the hydrogen-rich compounds are preferential considered. Considering the reaction cross sections of the <sup>1</sup>H(n, el), <sup>12</sup>C(n, p)<sup>12</sup>B, <sup>12</sup>C(n, d)<sup>11</sup>B, <sup>12</sup>C(n, t)<sup>10</sup>B, <sup>12</sup>C(n, <sup>3</sup>He)<sup>10</sup>Be, <sup>12</sup>C(n, α)<sup>9</sup>Be and <sup>1</sup>H(n, γ)<sup>2</sup>H, polyethylene and polypropylene are suitable for serving as targets in this research. Based on a 3U PXIe, digitizers with 1 GSps sampling rate and 12 bit resolution are utilized to digitize and record the output signals of telescopes. The time and amplitude information of each signal are extracted from its recorded waveform. Proton fluxes can be calculated by using the neutron energy spectrum and the cross section of the <sup>1</sup>H(n, el) reaction. Using the γ-flash event as the starting time of the time-of-flight (TOF) and the time information of signal in detector as the stopping time, the kinematic energy of each secondary proton can be deduced from the TOF and the angle of the detector. A calibration experiment on three charged particle telescopes, with each telescope consisting of a silicon detector and a CsI(Tl) detector, is carried out on this research platform. The readout methods of the CsI(Tl) detectors in these three telescopes are different. In the calibration experiment, Δ<i>E-</i><i>E</i> two-dimensional spectra and amplitude-<i>E</i><sub>p</sub> two-dimensional spectra of these telescopes are obtained. Through comparing these particle identification spectra, the SiPM is chosen as the signal readout method for CsI(Tl) detectors in the charged particle telescopes. These researches provide experimental evidence for the construction of the charged particle telescope at Back-n, and also illustrate the feasibility of wide-energy spectrum proton calibration based on the Back-n white neutron source.