Trapping of Helium Ions and the Re‐Emission of Trapped Atoms from Molybdenum
Autor: | L. J. Varnerin, J. H. Carmichael |
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Rok vydání: | 1957 |
Předmět: | |
Zdroj: | Journal of Applied Physics. 28:913-919 |
ISSN: | 1089-7550 0021-8979 |
DOI: | 10.1063/1.1722887 |
Popis: | The electrical cleanup of helium on molybdenum surfaces has been investigated. In this case, the phenomenon can be described by a trapping of ions upon impact with the surface. Measurements of the trapping efficiency η (atoms removed/ions collected) have been made over a range of ion energies from 150 to 2600 ev. The re‐emission of trapped helium atoms was investigated in detail. The contribution of re‐emission to the pumping process is described by a phenomenological theory. The results indicate that the trapping efficiency is lowered by a short time re‐emission of trapped atoms. Through the long‐time re‐emission of atoms, the theory accounts quantitatively for the observed saturation of the cleanup process. |
Databáze: | OpenAIRE |
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