Low-temperature specific heat and thermal conductivity of neutron-irradiated lithium fluoride

Exposure of LiF to radiation within a reactor reduces the low-temperature thermal conductivity and creates an excess specific heat. These properties are similar to those observed in samples exposed only to γ-irradiation and, for our sample, could be accounted for by the integrated γ-exposure alone. The low-temperature behavior can be explained by invoking various kinds of defects such as fluttering dislocations or clusters (extended defects) having a spectrum of shapes and sizes. The two-level-states found in reactor-irradiated SiO₂ cannot be identified in the irradiated LiF.