Design of a Mercury Vapor Target X-Ray Tube

Abstract

A mercury vapor target x‐ray tube has been constructed and utilized for bremsstrahlung studies. An electrically heated boiler at the bottom of the target chamber vaporizes mercury which is expanded through a nozzle to form the target. The mercury jet expands into a water‐cooled condenser at the top of the target chamber and the liquid mercury is returned to the boiler. A Pierce type electron gun provides the bombarding beam which exits from the high vacuum beam‐formation region through a 3‐mm‐diam aperture into the higher pressure target chamber. The radiation produced can be observed from ports in the target chamber wall. The apparatus is operable up to 30 kV with beam currents as high as 50 mA. The equivalent solid thickness of the target ranges up to 500 Å, which yields a photon intensity near the high frequency limit comparable to that from a solid target. Design and operational features of the device are discussed.