Range measurements in oriented tungsten single crystals. III. The influence of temperature on the maximum range

Abstract

The maximum range, Rmax, of 42K ions along the [Formula: see text] axis in tungsten has been measured over the temperature region 30–725 °K, by means of the anodizing/stripping technique. The results show that Rmax is completely independent of the lattice temperature, within an experimental precision of ± 3%. The prominent supertail (~10%) observed in 42K range distributions at 30 °K interferes with the evaluation of Rmax. This tail, however, can be completely suppressed by subsequently bombarding the crystal with a higher dose (3 × 1015/cm2) of Ne ions of similar energy while still at ~30 °K.The main conclusions derived from this series of three papers on range measurements in tungsten single crystals are briefly outlined. We find that Rmax is an extremely useful experimental parameter for characterizing the range distribution of channeled ions. Its value in tungsten is determined almost entirely by electronic stopping, except at energies less than a few keV. The electronic stopping powers derived from the energy dependence of Rmax agree roughly with theoretical predictions; however, the observed stopping power values exhibit large oscillations about the smooth theoretically predicted dependence on Z1, the atomic number of the projectile. An adequate explanation of these Z1 oscillations is not yet available.