Fast warm dispenser cathodes - modified standard designs

Abstract

Several current and future mini TWT applications require fast (2.5 -6 second) turn on of the TWT and hence the cathode-heater assembly it contains. This work was intended to develop low cost modified standard cathode/heater designs to achieve these requirements. !Traditional dedicated designs (bombarders, metal potting, multiple heaters), with their associated high costs, are available, but a low cost alternative is also desired for many applications. Standard cathode-heater designs currently in use in mini TWT's have been modified to enhance the warm up performance. Flexible designs have been produced with minor heater modifications, mass reductions, and configuration changes.Semicon Associates has assembled a dedicated set of equipment to evaluate the fast warm up performance of dispenser cathode heater assemblies. A programmable power supply that can simulate the end user's power supply and a fully capable data acquisition system are included. Assemblies can be exercised and evaluated as required. Temperature is monitored using single or two color pyrometers. 0-7803-7256-5/02/$10.00 0 2002 IEEE 307