Monte Carlo simulation on optimal design of neutron shielding for Am-Be source

Hydrogen-rich material is currently used as shielding material in the conventional container of ²⁴¹Am-Be neutron source, which causes the protective bucket large size, low efficiency and difficult to transport to well logging field. In this work, two different shielding materials are determined. And Monte Carlo simulation method is employed to optimize the thickness and combination mode of that filling material. Results show that the optimal volume and weight of protective tank is 0.187 m³ and 430 kg, respectively. Particularly, 13 centimeters thick tungsten is select as the inner shielding layer and 18 cm thick boron polyethylene is chosen for thermal neutron-absorbent as the outer layer, and the radiation levels of concerned location is evaluated using MCNP code. It can be conclude that the dose rate of the outside is less than 0.025 mSv·h^-1, which meet the requirement of relevant standards. (authors)