Titanium Getter Pumps

Abstract

Since the titanium getter pump was investigated by Prof. Herb in 1954, it has been recognized that it is a powerful tool to obtain “clean vacuum”.In Japan, valuable improvements were done by the group associated under Prof. Kumagai (J. Vac. Soc. Japan 1 22, July 1958), subsequent work has followed in Japan Vacuum Engineering Co. Ltd., and applications have been found both in nuclear machines and in some industrial high vacuum instrument such as vacuum sintering furnaces, metal vapor coating units and small electron beam furnaces.Many difficulties were experienced in manufacturing and operating the continuous evaporation type (Herb type) titanium getter pumps. In this paper cautions to be paid for troubles to be encountered in continuous running, effect of back-pumping by means of a diffusion pump on boosting a pumping speed, and ultimate pressure, are described.Conclusions for Herb type pump are as follows ; in the present step, it is not suitable for ultra-high vacuum application, while its ultimate pressure is limited in the region between 10-7 to 5 × 10-8 mmHg. The occluded gas in the titanium wire released during continuous feeding and evaporation may be a gas source which limit the ultimate pressure. But it may be useful for obtaining 10-6-10-7 mmHg in short pumping time in cooperation with the diffusion pump. It is better to appreciate the titanium getter pump as one of good trap for active gases, but poor one for inert gases and organic vapors.Flashing type absorber pump is very simple in construction, but is suitable for metal ultra-high vacuum system when it is used with a L - N trap and a diffusion pump.Triode type pump such as Huber's, and Alpert's, or Hall's modyfication of Penning type pump are suitable for glass ultrahigh vacuum system, because they have appreciable pumping speed for helium. Desorption of the occluded gases, however, will be a problem.