An Approach to the Study of Genetic Effects from the ¹⁴N(n, p)¹⁴C Reaction for Thermal Neutrons

Summary

The genetic effect of the nuclear reaction ¹⁴N(n, p)¹⁴C was evaluated in a tomato cross; dry pollen with a known chemical composition was exposed to a thermal neutron flux of 4·1 × 10⁷ n cm⁻² sec⁻¹ plus 11·6 rads/h gamma contamination.

For this purpose plants were fed ¹⁵N in place of ¹⁴N from the beginning of growth.

For seven criteria of radiosensitivity (reduction in seed-set and mutation frequencies in F₁) the radiation effect was reduced by half to two-thirds as a consequence of this change.

As the second capture reaction, ¹⁰B(n, α)⁷Li, was similarly controlled in the same material, the degree of genetic effect of both reactions could be compared. They were found to be independent and additive, the nitrogen capture reaction being the more important, partially because of a larger effect per rad.

The gamma component of the beam also provided a basis for an estimation of RBE. This would lie, for the ¹⁴N reaction, in the neighbourhood of 1·5 to 3·0 in the present conditions.