Life test evaluation of 411M cathode for highly reliable satellite TWTs

We evaluated 218 411M cathodes in a cathode test tube CTT.through continuous operation. These cathodes have been evaluated at four operating temperatures between 910 and 1100 Cb, and six types of current density from 0.6 to 5.0 Arcm2 for 100,000 h or more. The total accumulated life test time was 7,513,400 h. We formulated a life prediction model based on optimum operating temperature and cathode current density. The results of evaluation verified the validity of the life prediction model, which showed that the 411M cathode has a life of more than 200,000 h 22.8 years.at a current density of less than 2.0 Arcm2. q1999 Published by Elsevier Science B.V. All rights reserved.