Spectral dependence of the FeSO4 G-value in DT neutron beams

Ferrous sulphate G-values for DT neutron beams have been measured using ionization dosimetry based on a number of different ion chamber systems. Measurements were made in neutron beams with (a) minimum scattering material present so that only 13% of the neutron dose was due to low energy neutrons (mean energy approximately 1.3 MeV) and (b) a uranium block in the beam to increase the low energy neutron component to about 57% (mean energy approximately 1.5 MeV). In both cases the gamma -ray component was only about 5%. The results for the mixed neutron and gamma -ray beams were (a) 9.7+or-0.6 and (b) 8.8+or-0.6. G-values for neutrons of nominal energy 14.3 MeV and 1.5 MeV were estimated from these results to be 9.6+or-0.6 and 7.6+or-0.9.