The Performance Study Of Neutron Flux Monitor Based On Scintillator And Cherenkov

With the development of nuclear science and technology,neutrons technology have been widely used in various disciplines,which greatly promoted the research on neutron detection methods and neutron detectors.Especially in the development of nuclear technology in the industrial field,the real-time online detection device for industrial materials based on the prompt gamma ray neutron activation analysis?PGNAA?technology often uses a neutron generator with high neutron yield as the neutron source term,but neutron detection may have unstable neutron yields,so monitoring neutron flux is particularly important.³He proportional counter has the characteristics of high thermal neutron detection efficiency,insensitivity to gamma rays,and ease of use,it is widely used in neutron detection.However,due to the lack of ³He gas,the ³He proportional counter is expensive,so the new neutron detector developed is of great significance.A neutron flux monitor based on scintillator and Cherenkov has been demonstrated for neutron flux monitoring of D-T neutron generators.In order to expand the application field of the detector and further understand the relevant performance indicators of the detector,this paper conducts a more in-depth study on the performance parameters such as measurement accuracy,energy response,distance response and detection efficiency of the detector.The main contents are as follows:?1?The detector prototype package was completed for the previously developed detector prototype.The GEANT4 software was used to simulate the incident detectors of different neutron sources,the counts of the scintillator and Cerenkov layers in the different neutron-gamma mixing fields were obtained.Then,according to the simulation results,three unknown parameters in the neutron counting calculation formula of the detector under different neutron source illumination are obtained for the calculation of the detector neutron count in the subsequent performance test.?2?The GEANT4 software simulation and experimental measurement are combined to study the detector-related performance parameters.Through the repeatability measurement of the ²⁴¹Am-Be neutron source,the precision of the detector is 0.79%.the response curve of the detector is obtained by simulating different energy neutrons,then the results of the experiment are combined with the simulation to obtain the response of the detector to the neutron source of ²⁴¹Am-Be neutron source,²⁵²Cf neutron source and D-T neutron generator.It is proved that the detector is suitable for the measurement of the above three neutron sources and has a certain response to neutrons with energy between 150keV and 14MeV.Based on the experiment and simulation of the ²⁴¹Am-Be neutron source experimental platform,the response law and fitting equation of the detector for different distances are obtained.The angular distribution of the neutron source is measured,and the ³He proportional counter is used for comparison.The results show that the two detectors have good consistency at different angles,which proves that the detector is measuring the accuracy of the neutron source angular distribution.?3?The detector is absolutely scaled by the activation method.The absolute neutron flux and the neutron source yield are given by the activation measurement.Then intrinsic detection efficiency and the absolute detection efficiency of the detector are 20.2%and 0.130%,respectively.The detector after the calibration is monitored by the actual neutron flux,and the measurement result of the detector is compared with the result obtained by the activation method,the measurement error of the detector is4.58%.This proves that the absolute calibration result of the neutron flux monitor has certain accuracy.