Design parameter investigation of a cold-cathode Penning ion source for general laboratory applications

Abstract

An investigation of different design parameters of a cold-cathode Penning ion source is described. The Penning source had an iron cathode body, samarium cobalt permanent magnet, stainless steel anode and iron cathode faceplate. The faceplate extraction orifice diameter, anode shape and permanent magnet location were adjusted. Discharge current–voltage characteristics and current to a grounded target were measured for the different ion source configurations. Results indicate that for hydrogen and helium operation, the largest orifice, cylinder anode and baseline magnet location provides optimum source operation. Specifically, a continuous positive hydrogen ion target current of 1.0 ± 0.15 mA was attainable at only 1.6 × 10−4 Torr of pressure. At 1.0 mTorr of hydrogen pressure a target current of 2.0 ± 0.15 mA was possible. These results far surpass the design goal of 1 mA hydrogen ion beam at 1 mTorr of pressure. This cold-cathode Penning ion source design has potential application in a wide variety of laboratory research and development projects.