Probe Development And Performance Studying Of Space Neutron Detector Based On Plastic Scintillator

Space environment contains all kinds of environmental factors,including space radiation environment which contains a variety of radiation fields that will cause radiation damage to astronauts with space missions and spacecraft.Different particles have different damage mechanisms and characteristics.However,with deep space exploration missions’time span,space radiation especially space neutron damage effect,has drawn more attention.In this paper,to achieve space radiation’s especially neutron’s detection,plastic scintillator with high neutron sensitivity and bioequivalence is used combined with fast response,low noise and high sensitive SiPMs to assemble photon collection system forming the probe.Then with electronics,digital acquisition and process system a detector formed and experiment data was used for research.In the above process,the probe is designed with different sizes of plastic scintillator,different sizes and types of chamfer.With improvements of data processing methods,experiment suggest when the chamfer size changing from 40mm high to 12mm integrated chamfering scheme,the energy resolution of the scintillator improved.Linear energy calibration and nonlinear scaling are accomplished using exemptionγsources ⁶⁰Co,¹³⁷Cs and ²²Na making the single energy characteristics more obvious.Secondly,the high atomic number doped scintillator’s discrimination of neutron,gamma or even charged particles is realized by the PSD method.By using the gated measurement technique,the width of short gate is adjusted from 100 ns to 20 ns by fixing the width of long gate,and the FOM value is accordingly increased from 0.71 to 1.22,improving discrimination ability.The utilizing of ROI and background deduction extracted the detector’s energy resolution for 11MeV single energy neutron up to 22%.The double-end coincidence time corresponding to the highest percentage of true events is obtained from the detecting efficiency-time relationship in order to set the self-coincidence time of the probe.Then,the research on double-ended events’modification function is completed to further increase the proportion of true events.In addition,main-sub coincidence measurement technology is utilized with plastic scintillator and LYSO crystal to experiment.After linear calibration of spectrum respectively,0.511MeV and1.275MeV peak were obtained.Fitting and comparing the energy spectrum with the theoretical one is excellently coincident,improving the neutron detection ability and the charged particles,gamma anti-interfere ability of the detector.Finally,the final probe of detector system was finished.