Design of Regulator for n/γ in Complicated Radiation Field

In oder to satisfy the spcial demand of some users on the radiation field,it is necessaary to further increase the n/γvalue（neutron-fluence-to-gamma-ray dose ratio） in CFBR-II.The regulator with Pb as the main material is designed,considering its well shielding capability to gamma-ray.The n/γvalues with different lead thickness have been given from theory calculation.Considering the effect of regulator on the neutron spectrum and the load capacity of the installation platform,the regulator consisted of 4 layers（1cm for each layer） is worked out,and the experimental measurements have been carried out.The results indicate that the experimental results accord with the calculational one within allowable error range.The n/γvalue in CFBR-II radiation field can be regulated within 1.07×10¹²cm^-2.Gy^-1 to 4.87×10¹²cm^-2.Gy^-1.