Application of Geant4 code to radiator degrader CR39 neutron spectrometer

Response functions of different thickness combinations are calculated by using the Geant4 code. It is concluded that the FWHM and the minimum detectable limit depend upon the thickness of polythene and aluminum layer respectively, while the peak value depends on both of them. The radiation experiments using the D-D neutron source are carried out to obtain the detection efficiencies for four different thickness combinations, which agree with the calculated results well and this verifies the reliability of the Geant4 code.