Abstract: Lineal energy spectra of novel SOI (silicon-on-insulator) microdosimeter and detector response in Cf-252 neutron and gamma mixed field and Co-60 gamma radiation field were simulated with GEANT4. The simulated results were compared with the TEPC monitoring experiments with good consistency. Some differences are identified and discussed. The effects of different conversion layer thickness on lineal energy spectra were analyzed. Through the simulation, it can be seen that the SOI detector could be used to distinguish the contribution of neutron from gamma. We also found that the thicker conversion layer could increase the peak values of gamma lineal spectra, which may be used for gamma dose measurement at various depth of tissue. These results provide valuable information for the design of the SOI microdosimeter.

Key words: SOI, microdosimeter, lineal energy, dose equivalent, GEANT4, mixed fiel