The G-value for the ferrous sulphate dosemeter for 14 MeV neutrons

Double strand-breaks and DNA-to-protein cross-links induced by fast neutrons in bacteriophage DNA

Coliphage T7 was suspended in tryptone broth and exposed to a mixture of fast neutrons and gamma radiation. Plaque survival, double strand-breaks and DNA-to-protein cross-linkage were examined and the results compared with those found in phage exposed to gamma radiation alone. Neutral sucrose density sedimentation patterns indicate that neutron-induced double strand-breaks sometimes occur in clusters of more than 100 in the same phage and that the effeciency with which double strand-breaks form is about 50 times that of gamma-induced double strand-breaks. Neutron-induced protein-to-DNA cross-links probably also occur in clusters with enhanced efficiency relative to low LET radiation.

The response of the ferrous sulphate dosemeter to neutrons

A semi-empirical method of calculating G-values for the ferrous sulphate dosemeter irradiated by neutrons up to 18 MeV has been developed. It utilizes published charged particle G-values along with particle spectra calculated for mono-energetic neutron interactions with the dosemeter medium. All available G-value measurements with neutrons have been evaluated and compared with values predicted by this method. The agreement was excellent for DT generator and cyclotron neutron beams in which the neutron spectra had been accurately determined. However, the predictions could not be completely confirmed for lower energy neutrons becuase of the large experimental uncertainties in the measured G-values and the lack of detailed information on the neutron spectra.