Damage kinetics in MeV gold ion - Irradiated crystalline quartz

Damage creation in crystalline alpha-quartz under gold irradiation was studied at 1.0 and 5.5 MeV using the ARAMIS accelerator at CSNSM (Orsay). Although at these energies the total stopping powers are nearly equal (respectively, 4.20 and 4.46 keV nm(-1)), the electronic stopping power is only 1.23 keV nm(-1) (25% of the total) at 1 MeV while it reaches 2.75 keV nm(-1) (62% of the total) at 5.5 MeV. The electronic stopping power threshold for damage creation in alpha-quartz is about 1.8 keV/nm [1]. The experiment thus allows us to follow the damage production kinetics due to nuclear collisions (at 1 MeV) versus electronic collisions (at 5.5 MeV), The damage was determined by channeling Rutherford backscatteriag (RBS-C) using the 2 MV Van de Graaff at DPM (Villeurbanne). Single ion impacts create damage when electronic stopping dominates, while several impacts are necessary to achieve complete damage when nuclear stopping dominates. Differences in damage efficiencies will be discussed. (C) 2000 Elsevier Science B.V. All rights reserved.