Development of a portable transfer standard for the neutron source yield measurement using Fluka simulation

A novel light weight portable transfer standard has been developed for the standardization of the laboratory neutron sources conforming to in-situ measurements. Fluka simulation was used to optimize various design parameters in such a way that it has almost constant efficiency for the neutron energy range of few keV to 10 MeV and also for the commonly available laboratory neutron sources. The optimized total length and radius of the system is 39.4 cm and 13.5 cm, respectively. The weight of the system is about 22 kg. The efficiency of the system obtained from experiment for four laboratory neutron sources (241Am-Be, 241Am-B, 252Cf and 241Am-F) is constant within the deviation of ±8% having the average value of 2.85 counts/n.cm2. The efficiency of the system was also calculated from Fluka simulation. For mono-energetic neutrons from 1 MeV to 10 MeV the efficiency of the system was found to be constant within ±10% having the average value of 2.9 counts/n.cm2 and for the above mentioned four neutron sources also it is constant within ±4% with the same average value.