Atomic Energy Science and Technology ›› 2020, Vol. 54 ›› Issue (3): 385-393.DOI: 10.7538/yzk.2019.youxian.0481

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Measurement of Beam Profile of CSNS Back-n

HAN Changcai;OUYANG Xiaoping;ZHANG Xianpeng;SONG Zhaohui;BAO Jie;YAN Weipeng   

  1. Northwest Institute of Nuclear Technology, Xi’an 710024, China;China Institute of Atomic Energy, Beijing 102413, China
  • Online:2020-03-20 Published:2020-03-20



  1. 西北核技术研究院,陕西 西安710024;中国原子能科学研究院,北京102413


The measurement of neutron beam profile will provide fundamental data for subsequent nuclear data measurements and other physical experiments. A high performance intensified CMOS camera based on neutron energy resolved imaging system with time-of-flight technique was developed at China Spallation Neutron Source, and its spatial resolution is less than 1 mm. Some typical characteristic parameters of the neutron beam, such as beam profile, beam size and non-uniformity were obtained and analyzed. At ES1 and ES2 (experiment station 1 and 2), which are about 55 and 75 m away from the target respectively, the FWHMs of neutron beam profile are 55 and 63 mm respectively, and the full widths of 75% maximum are 50 and 60 mm respectively, and the beam profile is well-defined and step like. The results show that the beam profile, size and non-uniformity are not dependent on neutron energy, even the non uniformity in the center of the beam profile is less than 10%. With the well-defined contour and elegant non-uniformity of the beam profile, the nuclear data can be measured successfully.

Key words: China Spallation Neutron Source, Back-n, time-of-flight, nuclear data measurement


中国散裂中子源(CSNS)反角白光中子(Back-n)束斑品质是核数据测量和其他物理实验的基础。利用像增器脉冲选通特性和飞行时间法搭建了一套具有时间分辨能力的成像系统,其空间分辨小于1 mm,初步实现了束斑轮廓、尺寸和非均匀性等特性参数的测量和定量分析。在距散裂靶约55、75 m处测得束斑FWHM分别为55、63 mm,对应峰值强度约75%处束斑直径分别为50、60 mm,且束斑边缘陡峭,呈台阶状。分析表明,束斑轮廓、尺寸和非均匀性等特性参数均与中子能量无关,在束斑中心区域80%范围内非均匀性小于10%。测量结果表明,CSNS反角白光中子源物理终端具有较好的中子束斑品质,可开展较高精度的核数据测量。

关键词: 中国散裂中子源, 反角白光中子, 飞行时间, 核数据测量