LONG-LIFE COLD CATHODE STUDIES FOR CROSSED-FIELD TUBES
Abstract
Tests on the effects of high current-density electron bombardment (0. 75 A/sq cm) and of residual oxygen (approximately 0.000015 Torr) on the secondary emission ratio (delta) were performed in the Electron Bombardment Vehicle (EBV). Delta sub max for a 300A electron-beam-evaporated layer of alumina on molybdenum increased from 2.0 to 3.8 due to O2 pressure of 0.000015 Torr, and decreased from 3.8 to 2.0 due to 0.75 A/sq cm electron bombardment without oxygen. Delta sub max for an anodized beryllium target (300A oxide layer) increased from 1.9 to 3.0 under the same O2 treatment. Operation of the QKS1397 CFA test vehicle for more than 200 hours has shown that the available emission (using the O2 dispenser) from an evaporated aluminum-on-copper cold cathode appears to have stabilized near a peak current of 40 amperes (approximately 2A/sq cm) at a 0.002 duty factor. Approximately 70 hours of operation were obtained at 2.5 A/sq cm.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1968
- Accession Number
- AD0837414
Entities
People
- C. Mcgeoch
- L. Lesensky
- M. Arnum
Organizations
- RTX