Capture-gated Technology For Lithium Compounds On Organic Scintillator Surfaces

Sensors are an important component of the control system,which can sense the information needed to be measured and convert it to output.High-precision sensors are indispensable to the control system,and have important technical support for improving the reliability of the control system.Space neutron detector is a kind of sensor.The sensitivity of probe determines the quality of space neutron detection system.In this paper,the neutron detection technology is mainly studied.The plastic scintillator probe is used as the sensor of the neutron detection system to sense the neutron radiation field.Capture-gated Technology is a new means to further enhance the reliability of neutron detection system.In this paper,the application of capture gating technology in neutron detection is realized in a novel way.The main work of this paper is as follows.First of all,the probe is the core module of space neutron detection system.In this paper,plastic scintillators,reflectors and photomultiplier tubes are screened and evaluated to form a probe with high sensitivity.Secondly,the photomultiplier tube used in this paper will produce noise signal.The two-terminal signal correlation method is used to integrate the length of the two ends and use the merging algorithm to suppress the noise signal.Finally,the capture-gated technique is used for neutron detection,in which lithium compounds are added to the detector to detect charged particles generated by thermal neutrons captured by ~6Li.Firstly,different lithium carbides were prepared for experimental comparison,and the experimental results of different lithium carbides were compared.Lithium carbonate and lithium chloride were selected as lithium carbides for capture-gated experiments.Then the selected lithium compounds were tested in the neutron gamma radiation field,which not only realized the identification of n/γ,but also realized the detection of charged particles generated after neutron capture.The experimental results show that the fast neutron signal is detected by the scintillator detector,and then the charged particle signal produced by the slowed thermal neutron captured by ~6Li is detected.Through the correlation of the two signals,the neutron can be accurately identified,which not only realizes the detection of neutron energy,but also realizes the particle identification.Therefore,the capture-gated technology combined with the two-terminal signal correlation method improves the reliability of the neutron detection system.The FOM value of the detector can reach 1.05 and the energy resolution is 22%.