Total sputtering yield of Nb bombarded by MeV heavy ions

Abstract

The angular distribution and total yield of atoms sputtered from polycrystalline Nb by 70 MeV 79Br 7+ ions have been measured. For comparison, measurements have also been made using 100 keV 40Ar + and 100 keV 79Br + projectiles. Targets were sputtered in ultra-high vacuum and sputtered material was collected on cylindrical AI foils. The areal density of collected material was subsequently determined by Rutherford backscattering using 850 keV 4He + and 15 MeV 16O 3+ incident ions. The low energy results were consistent with previous measurements in this energy regime where collision cascades are the dominant sputtering mechanism. For the 70 MeV Br irradiation, we measured a total yield, Y = 0.14, which is also consistent with a collisional description of the sputtering process.