'SPUTTER-ION PUMPS: PERFORMANCE-ASSESSMENT AND NOBLE-GAS PUMPING OPTIMISATION IN VIEW OF THE COMBINATION WITH NON-EVAPORABLE GETTERS'

The pumping properties of sputter-ion pumps (SIPs) have been studied in view of the combination with non-evaporable getters (NEG) for ultra-high vacuum applications. Several diode and noble-diode SIPs have been tested on a dedicated test bench and a specific procedure has been tuned, which allows to obtain reliable and reproducible values of pumping speed after saturation for different gases. In addition, several innovative combinations of cathode materials have been investigated, aiming in particular at an optimised pumping of noble gases and methane. These gas species cannot be pumped by NEG and thus their sorption represents the main task of a SIP in a combination pump. In parallel, each pair of cathodes has been analysed by FESEM/EDX and XRD, in order to find any possible correlation between their crystal structure, the surface modifications occurred during their functioning and the measured sorption performances.