Frenkel pair creation and stage I recovery in W crystals irradiated near threshold

Abstract

Abstract Single crystals of tungsten have been irradiated with electrons in the energy-range 1.4–1.8 MeV, perpendicularly to the three planes (100), (110) and (111). After elimination of the subthreshold effects, the threshold energy for atomic displacement has been determined for the major crystallographic directions. It is found to be minimum in the <100> direction: T100 = 42±1 eV, and only slightly higher in the <111> direction (7111 = 44 ± 1 eV). Three isochronal anneals were performed after irradiations at 1.6, 1.65 and 1.7 MeV. The recovery of the Frenkel defects was found to be nearly complete at 44 K. The analysis of the recovery spectra as a function of the incident electron energy as well as of the sample orientation leads to attribute the 38 K peak to the correlated recombination of freely migrating interstitials. The 11 K and 17 K peaks are attributed to close pairs produced respectively through <100> and <111> displacements.