Monte-Carlo simulation of Cherenkov light spot produced by underwater radioactive source

The removal cross section method and the buildup factor method have been used to calculate the dose equivalent distribution of neutron and gamma rays permeating through the primary shielding layer of underwater radiator respectively. With this distribution, Cherenkov light spectrum and flux distribution in 3 m water layer radiator after -rays permeating through secondary shielding layer and follow-up water layer have been simulated with Geant4. In addition, considering the geometry dilution and water attenuation for Cherenkov light propagating through some thickness of the pure water layer, the size of Cherenkov light spot and the intensity distribution were obtained.