LOW-ENERGY (10 TO 700 EV) ANGULARLY RESOLVED SPUTTERING YIELDS FOR D+ON BERYLLIUM

The phenomenon of ion induced sputtering is integral to many applicati ons. In magnetically confined fusion, this sputtering is important for both the lifetime of the plasma facing components and the contaminati on of the plasma. A method has been developed to obtain both the angul ar distribution and the total sputtering yield. The total yield is det ermined by collecting the sputtered material on a quartz crystal micro balance. The sputtered material is also collected on a pyrolytic graph ite collector plate. By mapping the concentrations of the sputtered ma terial on this plate, both the polar and the azimuthal angular distrib ution can be determined. Utilizing this set-up, data have been obtaine d for 10 to 700 eV D+ on beryllium at a 45 degrees angle of incidence to the normal. Subthreshold sputtering (0.004 +/- 0.003 at 10 eV) has been observed. These data are some of the first to become available, e specially at the lower energies.