Effects in the proton bombardment of NaF crystal, 1

NaF crystals were bombarded with protons of energy from 0.6 to 2 MeV at somewhat high temperatures, to have Na colloid in the proton-penetrated zone. The average projected range of protons was measured by thickness of the colloid layer. The range-energy relation obtained in the present study has little effect of the proton channeling and seems to be that for random directions. The microscopic cleavage profile in the beam direction included colored zone, separate colloid layers, microcracks, and turning of the cleavage steps, which appears to have close relation with the effects of resonant 19 F(p, α) 16 O reactions as well as the proton penetration itself. Their locations coincide with the range ends of the protons of incident and resonant energies and of the α-particles produced at 340.5 keV resonance. Hydrogen and oxygen with protons and α-particles may contribute to the occurrence of a local strain to initiate cracks.