The angle of incidence dependence of the sputtering energy threshold of tungsten in future nuclear fusion device

Abstract

The angle of incidence dependence of the sputtering energy thresholds (Eth) for tungsten targets irradiated by Helium, Tritium, and Deuterium ions was studied using two different simulation programs (RDS-BASIC and SDTrimSP). For each of the studied irradiation systems, the sputtering energy threshold was found to slightly decrease (3 to 6 eV) by increasing the angle of incidence of the irradiating ion beam. This decrease was found to vary from one irradiation system to another and give a minimum Eth value which was found to occur at a certain angle range for each system. Departing from this minimal Eth angles toward higher angles was found to result in an abrupt and more dramatic increase in the Eth values which can exceed the normal incident Eth values, especially at grazing angles. Our results were also compared and discussed in light of some existing theories.

Keywords

• Monte-Carlo simulation
• Plasma-facing materials
• Tungsten
• Ion irradiation
• Sputtering energy threshold
• Angle of incidence dependence