Technique for sealing emitter enclosures

Sealed emitters employed in non-destructive materials testing or in medical applications must meet stringent safety requirements. For this purpose, they are put in multi-component enclosure shells which must be joined gastight. The familiar techniques mainly employ enclosures consisting of two stainless steel components which are brazed or welded together. Because of the stringent requirements the systems must meet, most components of enclosures are electron beam or argon arc welded. Despite these sophisticated techniques, defects cannot be excluded. In a newly developed method the contact surfaces of the parts of the enclosure are coated with a high-viscosity liquid or paste which cures after the emitter has been added and the shells closed around it and in this way seals the enclosure. (orig.)