Surface production of negative hydrogen ions by reflection of hydrogen atoms from cesium oxide surfaces

Abstract

Negative hydrogen ions are produced by backscattering a thermal distribution of hydrogen atoms from a converter surface coated with a mixture of cesium oxides. The thick film of cesium oxide is produced by thermal decomposition of cesium carbonate and subsequent thermal activation aided by atomic hydrogen. About 60% of atoms with energies greater than 1.5 eV are reflected as negative hydrogen ions for a temperature of 0.22 eV in the thermal distribution. The H− ions have a Maxwellian parallel energy distribution with a temperature equal to the atomic temperature. Replacing the thermal source of hydrogen atoms with a discharge source results in H− ions of 1 eV temperature and 100 times lower intensity.