Speaker
Description
Due to its advantages such as evenly distributed pumping speed, low thermal outgassing and low photon and electron stimulated desorption yields, the non-evaporable getter (NEG) coating has been used in particle accelerators for years. Even though quaternary Ti-Zr-Hf-V coating deposited from an allow wire has been found to have the lowest desorption yields, highest sticking probability and sorption capacity, it is hard to manufacture such a target. Moreover, twisted wire targets occupy more space and are not good for coating narrow chambers. However, single element targets are widely available and can be produced in a form of a wire that is easy to apply for a uniform coating of various shapes of vacuum chambers. Pure Zr coating is tested to find a more efficient and cheaper way of producing the NEG coated chamber parts. In this work, three samples were coated with pure Zr (dense and columnar) and characterised, then results for pumping properties and electron stimulated desorption (ESD) were obtained. Pure Zr coating, although not as good as the quaternary NEG film, could be an economic solution in practise. It has been shown that columnar Zr coating can be activated at 160°C, the temperature close to the Ti-Zr-Hf-V activation temperature and lower than the one for the widely used ternary Ti-Zr-V alloy.
