Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (2): 20402-020402.doi: 10.11889/j.0253-3219.2016.hjs.39.020402

• NUCLEAR ELECTRONICS AND INSTRUMENTATION • Previous Articles     Next Articles

Performance measurement of large volume ø30 cm×30 cm gadolinium-loaded liquid scintillator detector

ZHU Chuanxin, MOU Yunfeng, ZHENG Pu   

  1. Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
  • Received:2015-10-17 Revised:2015-12-08 Online:2016-02-10 Published:2016-02-17

Abstract:

Background: The gadolinium-loaded liquid scintillator detector is an important tool for particle detecting in the area of high energy physics and nuclear physics experiments. Purpose: In this work, a large-size ø30cm×30cm gadolinium-loaded liquid scintillator detector has been developed for neutron measurement. Neutron gamma discrimination and distribution of neutron capture time of gadolinium-loaded liquid scintillator were main values of detecting performance. Methods: The n-gamma discrimination of the large-size gadolinium-loaded liquid scintillator detector has been studied using a 252Cf spontaneous fission neutron source by zero-crossing method. It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was poor. n-gamma discrimination spectra of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector within 1 μs after the fission event were captured with coincidence method based on the start signal of fission fragment from 252Cf fission chamber. Results: It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was also poor. The time distributions of neutron and gamma in the n-gamma discrimination spectra were measured by time-of-flight (TOF) technique and coincidence method. The peak time difference of neutron time distribution and gamma time distribution was 2 ns. The distribution of neutron capture time was measured for a ø30 cm×30 cm gadolinium-loaded liquid scintillator detector with coincidence method based on the start signal of fission fragment from 252Cf fission chamber. The main signals of γ by neutron capture of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector were in about 30 μs. The average time of neutron capture is 11 μs. Conclusion: The neutron capture time property of homemade gadolinium-loaded liquid scintillator meets the experimental requirements. For the most signal of neutron and gamma within the superposition, single peak was presented in the n-gamma discrimination spectra. Therefore, the n-gamma discrimination could not be realized. The phenomenon of the poor neutron-gamma discrimination property of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector was explained clearly based on the experiments.

Key words: Gadolinium-loaded liquid scintillator detector, Neutron gamma discrimination, The distribution of neutron capture time