We have studied the response of sapphire (a-Al2O3) to heavy-ion and electron irradiation at cryogenic temperatures using a high-voltage electron microscope. The structural changes were determined in situ during irradiation with 1.5 MeV Xe+, 1 MeV Kr+, and a dual beam of 1 MeV Kr+ and 900 keV electrons at temperatures from 20 to 100 K. At 20 K, a-alumina is amorphized by 1.5 MeV Xe+ at about 3.8 displacements per atom (dpa). The critical temperature for this amorphization was determined to be about 170 K. However, the material remains crystalline when irradiated at 26 K with a dual beam of heavy ions and electrons. The results demonstrate that electron irradiation can promote damage annealing, even at cryogenic temperatures, by causing the migration of point-defects produced in ceramics by ion irradiation.
Revised: June 13, 2019 |
Published: May 15, 1998
Citation
Devanathan R., W.J. Weber, K.E. Sickafus, K.E. Sickafus, M. Nastasi, M. Nastasi, and L.M. Wang, et al. 1998.Cryogenic Radiation Response of Sapphire.Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 141, no. 1-4:366-371.PNNL-SA-29463.doi:10.1016/S0168-583X(98)00190-6