Cesium gettering by graphite-improvement in the gettering efficiency

Author

Bhaskar, N.D. ; Kahla, C.M.

Author_Institution

Aerosp. Corp., Los Angeles, CA, USA

Volume

37

Issue

5

fYear

1990

Firstpage

355

Lastpage

358

Abstract

Results of experimental investigations of the cesium (Cs) gettering properties of graphite at various temperatures are reported. Possible reasons for this behavior are discussed. A model based on the grain boundary and surface diffusion of Cs in graphite is used to explain the results. Using this model, the activation energy for surface/grain boundary diffusion of Cs into polycrystalline graphite is estimated to be approximately 14 kcal/mole. The initial motivation was to examine the performance of graphite getters used in the cesium beam tube frequency standards. New results are presented regarding the dramatic improvement in the Cs gettering efficiency of graphite when heated to and maintained at elevated temperatures (100-130 degrees C) over the room-temperature efficiency.<>

Keywords

caesium; getters; grain boundary diffusion; graphite; surface diffusion; 100 to 130 degC; C:Cs; activation energy; beam tube frequency standards; elevated temperatures; gettering efficiency; grain boundary diffusion; polycrystalline graphite; surface diffusion; Atomic beams; Coatings; Collimators; Frequency; Gettering; Global Positioning System; Grain boundaries; Ovens; Satellites; Temperature;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/58.105241

Filename

105241