Measurements have been made of the total back-scattered D/sup -/ yields from Cs, Rb, K, Na and Li surfaces bombarded with D/sub 2//sup +/ and D/sub 3//sup +/ in the energy range 0.05 to 3.5 keV/nucleon. All measurements were made at a background pressure less than 10/sup -9/ Torr and the alkali-metal surfaces were evaporated onto a substrate in situ to assure uncontaminated surfaces. For each target, the D/sup -/ yield is at a maximum (as high as 12% per incident deuteron for Cs) between 150 and 300 eV/nucleon, and at any measured energy, the D/sup -/ yield decreases from Cs to Li in the order given above.

Experimental measurements of the production of H/sup -/ from surfaces bombarded with hydrogen are reviewed. Some measurements of H/sup +/ and H/sup 0/ production from surfaces are also discussed with particular emphasis on work which might be relevant to ion source applications.

The formation of negative ions by hydrogen collisions on cesium-coated surfaces is discussed in the limiting cases where the resident cesium is either in the purely ionic state or in the purely atomic state. The survival fraction for negative ions moving away from a metal surface is calculated using a method employing complex eigenvalues. The fraction of surviving ions is found to be larger than calculated by previous workers. The secondary emission coefficient for negative ion production by incident atoms with energies of ten to one hundred electron volts is estimated to be in the range thirty to fifty percent. The secondary emission coefficient is found to be a sensitive function of the thickness of the alkali adsorbate coating for ion energies in the range below a few hundred electron volts.

This article discusses K-shell x-rays of selected elements from Nb through Gd for incident protons and alpha particles from 0.6 to 2.4 MeV.

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