Estimation of neutron effective dose from DD and DT neutron generators and the design of appropriate shield for standing user

Neutron Generators (NG) are used as a neutron source for different applications. During recent years, major efforts are underway to develop a high yield compact NG. In this way, radiation protection aspects need to be considered during the operation of these high yield NGs. In this paper the neutron effective dose of a NG operator has been calculated using MCNPX Monte Carlo code. The results show that the neutron dose around a NG tube is highly dependent on the angle, distance and the type of NG (DD or DT). The dose due to DT source is 500 time higher than the DD source. Increasing the distance from 1 m to 5 m will decreased the dose up to 20 times. Increasing the distance is the effective way to reduce the dose rate but in a laboratory which there is not enough space, an appropriated neutron shield should be considered. The shields had designed in 6 different materials (ALF3, Borated-Polyethylene, concrete 806, Paraffin, Polyethylene,non-borated, Solid boric acid) and in thicknesses of 10, 20, 30, 40, 50 and 60 cm. The gamma flux, gamma effective dose, thermal neutron flux, epithermal neutron flux, fast neutron flux, total flux of neutron, and neutron effective dose components had calculated in a phantom spherical hypothetical shape. The results showed that Borated-Polyethylene shields for both of DD and DT source in thickness of 60 cm had the minimum neutron effective dose and also this shield in 60-cm thickness had lower gamma Dose than the other shields in both of the DD and DT source.