GB1191223A - Magnetically Confined Electrical Discharge Getter Ion Vacuum Pumps - Google Patents

Abstract

1,191,223. Ion pumps. VARIAN ASSOCIATES. 20 Aug., 1968 [23 Aug., 1967], No. 39741/68. Heading H1D. In a getter ion pump comprising an anode structure 4 having at least one discharge passageway traversed by a magnetic field B and insulated by a structure 13 from a cathode structure 5, a projection 6 of getter material extending from the cathode 5 into the passageway terminates substantially less than halfway along said passageway, thus forming a magnetron discharge zone 16 and a Penning discharge zone 18. Material sputtered from the projections 6 forms annular deposits 19 on the cathodes 5, thus improving the pumping of noble gases. The insulator 13, e.g. of alumina ceramic, is protected by an annular sputter shield 15 mounted on the anode support rod 9. The cathode plates 5 may be of Ti and the projections 6 of Zr, Mo or Ta to give increased sputtering. The projections 6 may be conical (Fig. 2, not shown), and a single projection extending into one end of the passageway may be used. A plurality of projections may be formed by folding a serrated metal sheet which is associated with a multi-cellular anode (Figs. 4 or 5, not shown). The projections 6 may be integral with the cathode plate 5 or may be insulated therefrom (Fig. 6, not shown) to enable the projections to be held at a lower potential than the cathode, thus providing a triode arrangement with reduced re-sputtering of the deposits 19.