Studying Of Correlation Measurement Method With Plastic Scintillator Array Detector

With the development of the aerospace business,the damage caused by the space radiation to the electronic components of the spacecraft and the astronauts cannot be ignored.Deep space radiation field is a complex mixed field with multiple particle types and wide energy spectrum,that puts forward higher request to the space exploration technology.In order to ensure the accuracy of energy measurement,multi-probe combination detectors are often used to complete the mission objectives.In this work,an array miniaturized radiation detector for aerospace field is built,which can achieve the neutron energy spectrum measurement and particle identification.Main research contents include:First,This work develops an array radiation detector,which consists of a probe sensing unit array,an analog signal processing unit,a digital unit and a data transmission unit.The probe sensing unit array is composed of three parallel 6×6×130mm plastic scintillators combined with a high-gain miniaturized silicon photomultiplier.The analog signal processing unit is composed of several integrated operational amplification microunits,which can realize signal amplification and I/V conversion.The digital unit can realize the 16 channels simultaneous input of signals and has the capability of high-speed pulse signal processing.The data is transmitted by optical fiber,which satisfies the storage requirement of high counting rate.Secondly,the two-sided sampling mode is adopted to realize the simultaneous readout of the two-terminal trigger signal in the process of signal acquisition.The photon signal transport in the scintillator has a correlation in the time domain.The trigger timing difference at both ends of the signal is limited by the parameter of internal timing window.The timing difference of true events is less than the window width.The setting of timing window width can effectively suppress false event interference and increase the proportion of true events.Finally,The motion track of true events when moving across multiple scintillator has direction consistency in the spatial domain.By introducing the parameter of external timing window to limit the average trigger timing difference between scintillators,This work obtained a multiple time correlation measurement method to effectively suppress the false event interference,and carried out experimental verification with the array radiation detector.The neutron source of ²⁵²Cf was used for experimental test,and the energy threshold was set to 2Me V.Under the condition that the internal timing windows are associated simultaneously of two scintillators but there is no external window,the FOM value increases from 0.67 to 1.22,and further increases to 1.39 under the condition that the external window is added.Under the condition that the internal and external timing windows are associated simultaneously of three scintillators,the FOM value is finally increased to 1.46.As the association condition increases,the FOM value increases.