Thumbnail
Access Restriction
Subscribed

Author Antoniazzi, A.B. ♦ Shmayda, W.T. ♦ Palma, T.
Source IEEE Xplore Digital Library
Content type Text
Publisher Institute of Electrical and Electronics Engineers, Inc. (IEEE)
File Format PDF
Copyright Year ©1993
Language English
Subject Domain (in DDC) Technology ♦ Engineering & allied operations
Subject Keyword Monitoring ♦ Laboratories ♦ Rough surfaces ♦ Surface roughness ♦ Pollution measurement ♦ Copper ♦ Surface contamination ♦ Atmospheric measurements ♦ Steel ♦ Temperature
Abstract Smearing is the most frequently used technique to determine surface activity. The technique is destructive, does not account for all the tritium adsorbed on surfaces and cannot track changes in surface concentration in real time. A relationship correlating the outgassing of tritiated species with surface activity as measured by smearing is sought. In vacuum technology significant efforts have been made to measure and derive relationships between outgassing rates and time, material and temperature. One major difference between outgassing in vacuum systems and outgassing from tritiated surfaces is the presence of one atmosphere of air. The interaction between air and the active surface may alter the outgassing spectrum commonly observed for unbaked vacuum systems. The tritium outgassing rate is measured by pumping room air continuously over the active surface in a chamber and through a tritium monitor. The real time airborne tritium concentration is correlated with the surface activity. Surface activities in the range of 5 to 200,000 /spl mu/Ci/m/sup 2/ have been examined. Outgassing rates in the range of 3 to 8,000 /spl mu/Ci/m/sup 2/.hr have been measured. Desorption of physisorbed HTO is most likely the dominant outgassing mechanism. For times shorter than 200 hours following a tritium exposure the surface outgassing rate decreases with a negative half power dependence on time.
Description Author affiliation: Ontario Hydro, Toronto, Ont., Canada (Antoniazzi, A.B.; Shmayda, W.T.)
ISBN 0780314123
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research ♦ Reading
Education Level UG and PG
Learning Resource Type Article
Publisher Date 1993-10-11
Publisher Place USA
Rights Holder Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Size (in Bytes) 406.49 kB
Page Count 4
Starting Page 975
Ending Page 978


Source: IEEE Xplore Digital Library