Low Flux Neutron Radiation Detection Technology

In recent years,there are more and more applications neutron technology in all areas of life,especially for the measurement of wide spectrum of low-level fission neutron becomes increasingly important.Boron-containing plastic scintillator detector have a high detection efficiency for low-intensity thermal neutrons and fast neutrons which is currently the preferred types of neutron detector.This thesis is based on Monte Carlo method,studied boron-containing plastic scintillator for neutron detection performance,and analysis the energy deposition flux characteristics when low intensity fission neutron incident to the boron plastic scintillator.And thus to lay the foundation for the further calculation of boron-containing plastic scintillator detection efficiency.The thesis mainly research method is by Monte Carlo method of numerical simulation,obtained in a variety of neutron source energy,boron-containing plastic scintillator diameter and length,the boron-containing plastic scintillator neutron detector performance.On the basis of the study,add polyethylene moderated for scintillator.Improve the neutron moderation by scattering with polyethylene moderator.It can increase the probability of neutron reaction with boron.Simulate moderator adding method in different ways and fine the best way.With our group's help,we set up the experimental platform.Measure the actual detector through experiments.The results show that the detection efficiency of boron-containing plastic scintillator detector will decrease with the incident neutron energy increase.The detection efficiency and energy deposition of the detector will increase with the increase of the diameter or length of the detector.By processing the data shows that,we can improve the neutron moderation and increasing the number of neutron in the scintillator through scattering when we add polyethylene moderated in the side of the scintillator.This is a good method to design detector.In the actual experiment,we tested Am-Li neutron source and Cf 252 neutron source and get some test data.The results provides help for the further development according to low flux fission neutron of high sensitivity boron-containing plastic scintillator detector.