Measurement of the 241Am–Li radionuclide neutron source spectrum

The neutron energy spectrum of an 241Am–Li radionuclide source has been measured in a low scatter room at the National Physical Laboratory, using a variety of spectrometers namely: a Bonner sphere set, a 3He ionisation chamber, and a set of proton recoil proportional counters. Calculations with the Monte Carlo multi-particle transport code MCNP have been used to explain some of the features seen in the spectrum. The data have been analysed using different unfolding techniques, and a final spectrum has been derived based on all the available measurements.