Cathode life test facility - historical review

Summary form only given. The cathode life test facility (CLTE) has performed real-time life testing of various thermionic cathode types since 1980. The facility originated at Rome Laboratories, Griffiss AFB. In 1992, it was moved to it present location at NSWC Crane, Crane Indiana. Since its inception, the facility has accumulated approximated 4 million total life test hours on cathodes of at least eighteen different types. Historically, the most popular cathodes under test have include reservoir cathodes, designated MK (Siemens), RV and V (CPI), and impregnated cathodes, Designated M (Semicon and Hughes), TM (CPI) and MMM (CPI). In addition, smaller numbers of more exotic cathode types have also been tested. Most cathodes are life tested at loadings of 1, 2, and 4 A/cm² in continuous emission mode. However, a number of cathode (e.g. cathode with 10 A/cm²) have been tested with applied filament power only, due to limitation on the test stations available. A summary of the cathodes tested over the entire life of facility is given and the result obtained is compared. Test vehicle configuration and methods of data collection and analysis are reviewed. Emphasis is placed on comparing different cathodes by type and loading. The usefulness of data is discussed.