Radiation Damage in a Rare‐Earth Silicate With the Apatite Structure

The effects of radiation on the rare‐earth silicate, Ca 2 Nd 8 (SiO 4 ) 6 O 2 , with the apatite structure was investigated using 244 Cm doping and alpha, gamma, and electron irradiations. Amorphization of the initially crystalline material was observed to occur only in the Cm‐doped material. Alpha irradiation produced measurable lattice expansions, with no tendency toward amorphization. The gamma and electron irradiations produced no measurable effects. The results indicate that the thermal spikes produced by the recoil nuclei emitted in alpha decay are responsible for the observed amorphization; the alpha particles produce isolated defects which contribute little, if at all, to the amorphization process; and ionizing radiation has no measurable effect on this structure.