PRODUCTION OF EXTREME HIGH-VACUUM WITH NON EVAPORABLE GETTERS

Producing pressures lower than 10(-12) Torr (XHV) at room temperature imposes severe constraints on the performance of materials and pumps. While today a wide choice of materials exists, only bakeable cryopumps and getter pumps are suitable for XHV applications. Non Evaporable Ge tter (NEG) pumps maintain their high pumping speed at the lowest press ures and therefore fulfil XHV requirements. The results presented here show that pressure in the low 10(-13) Torr and low 10(-14) Torr range s have been obtained in two different set-ups with a Zr-Al and a Zr-V- Fe NEG respectively.