Technical Papers and Presentations

The thermal load on the system components is one of the technical problems in the development of microfocus X-ray tubes. To improve their stability in long-term use, it is important to understand the physical phenomena and their influence on the system stability and filament lifetime. To improve our X-Ray WorX products, we apply the COMSOL Multiphysics® software to optimize the thermal load on the insulators as well as the target used to generate the X-rays. Joule heating mechanism, used to facilitate thermionic emission from the filament, generate a lot of heat that must be dissipated by the cathode assembly and insulator. The insulators in particular can cause problems from a dielectric and mechanical point of view, since they experience relatively high temperatures and thermal expansion under thermal load in the presence of strong electric fields. The decisive factors here are the vacuum conditions, the temperature distribution, the dielectric insulation strength by high-voltage application of up to 300 kV and the mechanical construction. We apply FEM to address the issue of thermal management and dielectric strength and to optimize the mechanical design of our cathode assembly and insulator.