Accession Number : ADA191498

Title :   A Scientific Basis for an Alternate Cathode Architecture.

Descriptive Note : Rept. for Sep 84-Dec 87,

Corporate Author : ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY

Personal Author(s) : Daniszewski, E J

PDF Url : ADA191498

Report Date : Feb 1988

Pagination or Media Count : 153

Abstract : The main effort of this research has been to try to bring together in a simplified manner both theoretical and experimental studies basic to the analysis of thermionic emission from Impregnated Dispenser Cathodes (IDC) as it is understood at this time. This study revealed two major areas of uncertainty: (1) the electronic and steric nature of the cathode emissive surface, and (2) the lack of a reproducible impregnation procedure. Mossbauer Spectroscopy was used to probe cathode surfaces and revealed that enhanced thermionic emission was concomitant with the presence of a low-spin state transition metal ion. The existence of the low-spin Mossbauer probe led to a formulation of a hypothetical surface considerations. This model had a striking parallelism with similar systems in the field of heterogeneous supported catalysis (HSC), viz., the hexagonal barium titanates (HBT). Keywords: Thermionic emission, Mossbauer spectroscopy, Differential thermal analysis, Crystal field theory, Metal metal bond.

Descriptors :   *ARCHITECTURE, *BARIUM TITANATES, *CATHODES, BONDING, CATALYSIS, CRYSTALS, DIFFERENTIAL THERMAL ANALYSIS, DISPENSERS, EXPERIMENTAL DATA, FIELD THEORY, HETEROGENEITY, IMPREGNATION, LOW LEVEL, METALS, MOSSBAUER EFFECT, PROBES, REPRODUCIBILITY, SPECTROSCOPY, SPINNING(MOTION), SURFACES, THEORY, THERMIONIC EMISSION

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE