Length Change of Copper and Aluminum after Electron Irradiation

With the new application of capacitance-change techniques, length-change measurements were made in conjunction with annealing copper and aluminum specimens above their electron-irradiation temperature of about 15°K. Damage rates at this temperature were also measured. The Stage I recovery of length change is compared with its resistivity counterpart. Remarkable correspondence is obtained to the degree that percentages of recovery of individual substages compare favorably, with the same defect inferred to be responsible for recovery in both cases. The production rate for length change was determined to be +1.8×10−23 cm2/electron for 2.2 MeV electrons. Linear bending with dose was observed. This bending was analyzed as due to electron straggling. The ratio of resistivity change to volume change and to stored energy for electron and heavy-particle bombardment shows good relative agreement. From the results, it was concluded that these physical-property changes do not depend sensitively upon Frenkel pair close-pair separation.