EFFECT OF BOMBARDMENT TEMPERATURE ON TRAPPING OF XENON IN SOME OXIDES AND HALIDES

This investigation was concerned with the effect of ion bombardment temperature on the subsequent release of xenon during post-irradiation annealing. For materials resistant to irradiation damage, increasing the bombardment temperature had little effect if the temperature was still low enough to avoid appreciable diffusion of the free gas atoms (T ≤ 0.4 Tmelting). An effect was observed with bombardment doses high enough to cause trapping of xenon, if the bombardment temperature was above that required for migration of the free gas but below that required for escape of the temporarily trapped gas. The retained gas in such samples will be primarily trapped gas, while a similar sample bombarded to the same dose at room temperature will contain both free and trapped xenon. A third effect was noted with MgO, which is subject to gross structural damage during irradiation. Samples bombarded at room temperature to an appreciable dose exhibited a large release of gas at low temperature coincident with the annealing of the damage, while samples bombarded to the same dose above the annealing temperature for damage exhibited normal diffusional release. © 1968.