A cathode assembly is for use in a radiation generator and includes an ohmically heated cathode, and a support having formed therein a hole and a recess at least partially surrounding the hole. In addition, there is a mount coupled to the support. The mount includes a larger outer frame positioned within the recess, a smaller inner frame carrying the ohmically heated cathode and spaced apart from the larger outer frame, and a plurality of members coupling the smaller inner frame to the larger outer frame.