SPUTTERING YIELDS.

Energy distributions have been determined for atoms sputtered from Cu 100, 110, and 111 surfaces as well as polycrystalline surfaces of about ten different target materials under Hg and noble-gas ion bombardment io the range 80 to 1200 EV. Energies of sputtered atoms are found to depend markedly on the angle of ejection and the mass of the incident ion. The most probable ener gy the energy at which the maximum occurs is nearly independent of bombarding-ion energy down to about 100 EV. At increasing bombarding-ion energy the high energy tail in the energy distribution becomes more pronounced and causes the average energy to increase. Finally, an asymptotic value is reached at about 1000 EV bombardingion energy. For Au-Ar the energy distribution at 1200-EV bombarding-ion energy is fairly similar to that at 43 KEV from Thompsons data with the average energies of 18.5 and 20.5 EV respectively. Author