Ultra Clean Leak Detection Techniques for the Development of Microwave Tubes

摘要

Leak detection in the sensitivity range of 10~(-9) to 10~(-10) std. CC/Sec is essential right from the sub-assembly stage up to the final integration of the microwave tube. These tubes in general require clean contamination free vacuum of the order of 10~(-7) ton or better for its optimum operation. In view of above, it becomes necessary to adopt ultra clean leak detection techniques in the development of MW tubes by avoiding the use of grease or wax during, the leak testing. This requires design of special fixtures for leak testing of various critical assemblies particularly for those having ceramic parts and multiple open ends. This paper presents the clean (grease/finger prints free) leak detection technique adopted for some typical assemblies of miniature helix TWTs.