Thermal neutron albedo and diffusion parameter measurements for monolithic and geometric voided reflectors

Experimental measurements of thermal neutron albedo (βthβth) and diffusion parameters have been carried out for monolithic as well as for water reflectors having spherical and cylindrical voids using Am–Be neutron source and BF3BF3-detector. The measured saturation values of βthβth for monolithic water reflector has been found be 0.80±0.0240.80±0.024, which is in good agreement with the corresponding value 0.81 quoted in the literature. In this case, the values of diffusion coefficient (DD) and diffusion length (LL) have been found to be 0.142±0.0210.142±0.021 and 2.57±0.032cm which are in good agreement with the standard values 0.144 and 2.755 cm, respectively. For water reflectors with spherical voids having 3.9 cm diameter, the saturation value of βthβth has been found to be 0.74±0.0180.74±0.018 and the values of DD and LL have been found to be 0.32±0.0430.32±0.043 and 4.39±0.059cm, respectively. In the case of a water reflector with cylindrical voids having diameter 2.54 cm and length 48 cm, the saturation value of βthβth and the values of DD and LL have been found, respectively, to be 0.74±0.0190.74±0.019, 0.41±0.0340.41±0.034, 5.79±0.067cm for parallel configuration and 0.78±0.0180.78±0.018, 0.347±0.0280.347±0.028, 4.22±0.056cm for the perpendicular configuration, respectively.