Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1690693 | Vacuum | 2006 | 6 Pages |
Abstract
The accuracy of results in experiments where a well-processed UHV system is exposed to hydrogen depends on the hydrogen absorption rate and kinetics of subsequent spontaneous release from the system itself. In experiments to date, the sensitivity required to detect very low rates has been achieved only when tritium has been used as a tracer gas. Unfortunately, tritiated water from the surface prevails among released gas species which is not expected for well-outgassed surfaces. In the present studies, UHV system behaviour at 303Â K during three deuterium exposures of duration 92 and 72Â h at an initial pressure of 1Â mbar was explored. The rate of decrease of pressure was constant during the whole of these periods as monitored by non-ionizing vacuum gauges. It corresponded to an effective sticking probability of the order of 1Ã10-12 and resulted in absorption of 5Ã1014 D atoms/cm2. The release kinetics were observed for several days starting immediately after deuterium had been pumped from the system. Initially, the deuterium release rate exceeded the background hydrogen outgassing by more than three orders of magnitude. These results demonstrate that extremely high sensitivity for deuterium absorption and release can be achieved with a precise pressure measuring technique otherwise attributed exclusively to tritium scintillation methods.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
Vincenc NemaniÄ, Bojan Zajec,