Practical problems in neutron dosimetry

The first problem discussed is the best phantom material. It is argued that tissue composition has a greater effect on dose distributions from photons than on those from neutrons. As water is normally used for photons, it should be satisfactory for neutrons, but checks are needed with high-energy neutron beams. Another serious problem is that of kerma ratios for neutrons above 20 MeV where highly discordant values have been calculated by several authors. Finally some suggestions are made about measurement of the gamma-ray component in beams of high-energy neutrons.