Single metal zirconium non-evaporable getter coating

Abstract

Non-evaporable getter (NEG) coating has been used for years in many particle accelerator facilities due to its evenly distributed pumping speed, low thermal outgassing, and low photon and electron stimulated desorption yields. In our earlier work, it has been demonstrated that quaternary Ti–Zr-Hf-V coating deposited from an alloy target in a form of a rod has the lowest desorption yields, the highest sticking probability and sorption capacity. In this paper, a single element Zr target has been explored. This type of target is widely available and produced in a form of a wire that is easy to apply for a uniform coating of various shapes of vacuum chambers. Two samples coated with Zr film of dense and columnar structure were analysed and results of the pumping properties and electron stimulated desorption results are reported. The results show that pure Zr coating could be an economic solution, despite not being as effective as can be achieved with a quaternary NEG film. It shows that columnar Zr coating can be activated and reaches full pumping capacity at 160 °C. This is close to the activation temperature of Ti–Zr-Hf-V film and lower than that for the widely used ternary Ti–Zr–V film. Single metal Zr coatings demonstrated that it could be a more efficient and inexpensive way of producing the NEG-coated vacuum chambers.