Efficient combining of ion pumps and getter-palladium thin films
- Varian S.p.A., Via Fratelli Varian 54, 10040 Leini, Torino (Italy)
Nonevaporable getters (NEGs) have been extensively studied in the last several years for their sorption properties toward many gases. In particular, an innovative alloy as a thin film by magnetron sputtering was developed and characterized at the European Organization for Nuclear Research. It is composed of Ti-Zr-V and protected by an overlayer of palladium (Pd), according to a technology for which the authors got the licence. NEG-Pd thin films used in combination with ion getter pumps is a simple, easy way to handle pumping devices for ultrahigh and extremely high vacuum applications. To show how to apply this coating technology to the internal surface of different types of ion pumps, the authors carried out several tests on pumps of various shapes, sizes (in terms of nominal pumping speed), and types (diode, noble diode, and triode). Special care was taken during the thermal cycle of baking and activation of the pumps to preserve the internal film from sources of contamination and/or from the sputtering of the titanium cathodes of the pump. Some important remarks will be made about the most appropriate conditions of pressure and temperature. The performance of the NEG-Pd-coated ion pumps was evaluated in terms of ultimate pressure and hydrogen pumping speed. The contribution of the thin film is particularly relevant for the pumping of this gas, due to its high sticking factor on palladium and the great sorption capacity of the underlying getter. Finally, the possibility of further improvement by substituting palladium with other Pd-based alloys will also be evaluated.
- OSTI ID:
- 21192368
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 26, Issue 4; Conference: 54. international AVS symposium, Seattle, WA (United States), 14-19 Oct 2007; Other Information: DOI: 10.1116/1.2834685; (c) 2008 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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