Use of discharge intensity for evaluation of pumping characteristics of a sputter ion pump

摘要

The pressure dependence of current in sputter ion pump has been investigated. Results may be fitted by a relationship I=kpn. The pumping speed after saturation, has been measured as a function of pressure. The proportionality between pumping speed and discharge intensity I/p has been verified. The exponent in the previous relationship is slightly larger than unity and it is expected that the pumping speed will increase with pressure. Experimental results are in good agreement with expectation, within a wide range of pressure. Measurement of the discharge intensity is therefore a good method to evaluate the pressure dependence of pumping speed for sputter ion pumps. With this method various sputter ion pump element structures have been tested.