LONG-LIFE COLD CATHODE STUDIES FOR CROSSED-FIELD TUBES
Abstract
The objective of the cold cathode study program is to achieve long life cold cathode performance for crossed-field amplifiers. Selected cold cathode materials will be evaluated as to: their secondary emission properties, their ability to withstand environmental factors expected in a crossed-field amplifier, and their crossed-field amplifier performance. Examination of samples sputtered in Ion Bombardment Vehicle, as well as measurement and observation of samples in Secondary Emission Test Vehicle, led to following conclusions: (1) 30% Mo - 70% Al2O3 films on Mo substrate exhibited sputtering rate of 0.007 molecules of Al2O3 per nitrogen ion; (2) Two hours of N2 sputtering of impregnated tungsten sample increased apparent porosity of surface from 15% to 47%; (3) Sputtering had no effect on K of Pt, while sputtering for 1-2 hours reduced K for nickel cermet and impregnated tungsten samples. Maximum secondary emission ratios K of 3.5 and 4.3 were measured respectively for GaAs and 200 A CVD BN samples. Measurements in Electron Bombardment Vehicle (EBV) demonstrated: (1) Secondary emission ratio maximum of 3.6 was maintained for 500A thick 30% Mo - 70% Al2O3 film on Mo substrate. Electron diffraction measurements showed K of Mo - Al2O3 film was reduced by agglomeration of Mo component to aggregates several hundred atoms in size.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1966
- Accession Number
- AD0801737
Entities
People
- C. R. Mcgeoch
- L. Lesensky
Organizations
- RTX