Decreases in deuterium pumping by St707 getter alloy caused by carbon dioxide preexposure
Intentional passivation of the deuterium pumping of the solid getter alloy St707 has been attempted by exposing samples of St707 to carbon dioxide at different pressures, temperatures and exposure times relevant for application to the getter modules in the ALT-I pump limiter. It was found that one of the most effective treatments examined was a 30 min, 1 Torr exposure at approximately 100 /sup 0/C. This preexposure kept the getter pumping speed less than 0.001 of its rated value for about 3 min when exposed to deuterium at 1 Torr and 30 /sup 0/C. After this ''incubation'' period, the getter speed increases to values greater than approx.1% of fully activated values. If left under high deuterium pressure, the getter eventually flakes off the substrate. Video observations of the flaking process indicate that individual particles leave the constantan getter substrate at velocities of 1 m/s. Attempts at passivating the getter using oxygen and carbon monoxide were found to be no more effective than using carbon dioxide, suggesting that there is no way to completely passivate the getter with these gases at pressures low enough for application to in situ getter arrays used in tokamaks.
- Research Organization:
- Physical Research Division I, Sandia National Laboratories, Livermore, California 94550
- OSTI ID:
- 5539055
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 3:3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaluation of Zr-V-Fe getter pump for uhv system
Pumping of methane by St707 at low temperatures
Related Subjects
DEUTERIUM
GETTERING
PUMPING
IRON ALLOYS
PASSIVATION
TOKAMAK DEVICES
VANADIUM ALLOYS
ZIRCONIUM BASE ALLOYS
CARBON DIOXIDE
GETTERS
IMPURITIES
VACUUM SYSTEMS
ALLOYS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CLOSED PLASMA DEVICES
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
OXIDES
OXYGEN COMPOUNDS
STABLE ISOTOPES
THERMONUCLEAR DEVICES
ZIRCONIUM ALLOYS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing