An emitter for a miniature X-ray apparatus comprises an insulating shell, an anode, and a cathode. The insulating shell includes a conical brazing surface, brazed to a conical brazing surface on the anode. The braze consists of a pure titanium layer and a pure tin layer. During brazing, the pure metals react and bond to the insulating shell and create a titanium-tin alloy between the pure layers. Pure tin is sputtered from tin sputter target onto the exposed brazing surfaces of the cathode cap and the anode. The insulating shell is placed in a vacuum chamber of deposition applicator, which deposits an active metal onto the shell brazing surface. In a brazing oven, the anode is placed within insulating shell such that the anode conical brazing surface and the shell conical brazing surface are contacting and aligned with each other. During brazing, the cathode is brought into contact with the insulating shell. The sealed emitters are placed in a sputtering machine's vacuum chamber. A metal is sputtered from a sputtering target to form a metal layer on the exterior of insulating shell.