Application of normal and high-pressure ionisation chambers for the determination of A150 kerma components in a 19 MeV neutron field

The twin-detector method was applied to determine the A150 plastic kerma components in a 19 MeV mixed neutron-photon field in free air. High-pressure ionisation chambers and thimble-type ionisation chambers at normal pressure were used. The spectral neutron fluence was measured to subtract the background neutrons and to evaluate the kerma factor for 19 MeV monoenergetic neutrons. The A150 plastic kerma factors derived from the various measurements agree well. They are higher than previously published experimental data, but about 7% lower than the value calculated by Caswell et al. (author)