Effect of Monoenergetic Fast Neutrons onn-Type Germanium

The density of vacancy-interstitial pairs produced per unit of fast-neutron flux on $n$-type germanium has been measured experimentally using monoenergetic neutrons. The changes in resistivity and Hall coefficient have been determined as a function of neutron flux and energy for $n$-type germanium having impurity concentrations of about 2×${10}^{12}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Both the irradiation and electrical measurements have been made at about 77°K. Neutron energies in the experiment were 4.8, 3.2, and 1.7 Mev from the ${\mathrm{H}}^2(d, n){\mathrm{He}}^3$ reaction and the observed changes in resistivity and Hall coefficients indicate charge carrier removal rates per unit of neutron flux, $-\frac{\mathrm{dn}}{d\phi }$, of 12, 12, and 21, respectively. Not only do the results appear much lower than the value of 160 calculated by current models, but they are less than would be estimated by extrapolating the results obtained with reactor neutron irradiations.