Role of Ionizztion in Radiatin Annealing

The role of ionization in the phenomenon of" radiation annealing" of graphite has been studied by using a I-MeV electron beam. Changes in the C-axis of a sample with a Hanford irradiation of 460 Mwd/ct were studied. Two thermal anneals of 4 hours each at 350{degree}C proved sufficient to complete the thermal annealing at this temperature. The samples were then irradiated for 7 {1I2} hrs at a temperature of 340 {degree}c. The samples received an irradiation of 47 microampere-hours, equivalent in ionization to an exposure of 200 Mwd/ct in a Hanford reactor. No changes were noted as a result of the electron bombardment. It is concluded that the ionization is not of major importance in radiation annealing