Non Evaporable Getter (NEG) Pumps: a Route to UHV-XHV

Non Evaporable Getter (NEG) technology has been developed in the 1970's and since then adopted by industry, R and D labs, research centres and in large physics projects like accelerators, synchrotrons and fusion reactors. NEG pumps are very compact and vibration-free devices able to deliver very high pumping with minimal power requirement and electromagnetic interference. In the present paper, main features and performances of getter pumps are reviewed and discussed with a special focus to photocathode gun application, where UHV or XHV conditions are mandatory to ensure adequate gun life. NEG coating and future challenges for NEG technology are also discussed.