Simulation and Analysis of 4H-SiC-Based PiN Fast Neutron Detector With Polyethylene Converter Using Geant4

Abstract When detecting fast neutrons, generally select materials with high hydrogen content, such as polyethylene and lithium hydride. It’s known that polyethylene is widely used and has high detect efficiency. Therefore, this paper uses Geant4 software to simulate 4H-SiC-based PiN fast neutron detector with polyethylene converter of varies thickness. With the increase of converter thickness, the conversion efficiency of 1–14MeV monoenergetic fast neutron will first increase and then decrease. By analysing the trend of conversion efficiency, the thickness is determined as 1000um. Then, the 1MeV, 2MeV, 4MeV and 8MeV monoenergetic neutrons and typical fats neutron source: Am-Be neutron source are simulated under the thickness of 1000um convertor, the particle types and energy distribution to the sensitive volume and the energy deposition of particles in the sensitive region are also obtained. Through the analysis of recoil proton energy spectrum, the relationship between incident neutron energy and recoil proton energy are studied. Also, through the analysis of PKA (primary knocked-out atoms) energy spectrum, we found that the main reactions in epi-layer are 28Si(n,n’) 28Si, 12C(n,n’) 12C, 28Si(n,α) 25Mg, 28Si(n,p) 28Al, etc. It is found that heavy ions such as C and Si produced by neutrons in sensitive volume account for a large proportion. The above research finally helps to investigate the deposit energy in the epi-layer.