The face plates of a drift tube have their joints with a central cylindrical body sealed by utilizating two metallurgical techniques. The first technique involves the soldering of interface surfaces at the joints between the face plates and the body. The soldered joint prevents the entry of electroplating solution into the interior of the drift tube during a second metallurgical procedure involving the electroformation of a copper strap around the joint which provides a permanent seal against leakage of coolant from the drift tube while offering excellent electrical and thermal conductivity across the surface of the drift tube.