Fabrication of quartz diaphragms for helium leak detection

The feasibility of 50 mm thick diaphragms with a metallic film heater integrated on a quartz disc and working up to 500 1C has been demonstrated. The diaphragms have been realized with the coupling of abrasive jet machining and mechanical polishing techniques. The metallic film has been obtained by means of a sequence of e-gun evaporation and electrochemical growth steps. No degradation of the adhesion characteristics was registered. Electrical properties were retained without electro-migration even for working conditions of 50 h at 500 1C. Aim of the device is the application in quartz molecular sieves thermally/electrically modulated, basically for helium leak detection.