How to achieve and maintain UHV and XHV levels
December 22, 2020
5 MIN READ
When pressure within the pump body is at 10-4 mbar or better, a high voltage is applied to the Titanium electrodes which results in an electron discharge. The powerful magnets, typically 1200 Gauss, attract and maintain these electrons within the anode ring as a plasma.
Residual gases within the anode assembly will collide with these free electrons. As a result of these interactions, electrons are removed from the valency shells of the gaseous elements and molecules. The resultant positive gaseous species are repelled from the positive anode to the Titanium cathode plates.
When the positive gaseous ions collide with the cathode, some of the titanium is sputtered from the surface. The gaseous species then react chemically and physically with the titanium and become trapped, thus providing a pumping mechanism akin to cryopumps.