Ion-beam source

The ion-beam source contains an annular anode and cathode which are arranged in a cylindrical housing (1) having end walls (2, 3). Mounted rigidly at one end on one of the end walls (2) is a rod (4) whose other end carries a disc. An annular hollow body (7) having an annular gap on the one end surface (8) is accommodated in the housing (1). An incandescent cathode (11) is arranged outside the housing (1), in the vicinity of the end surface (3) of said housing, with an annular gap. The housing (1) with the end walls (2, 3) and the rod (4) with the disc (5) consist of a soft-magnetic material, while the annular hollow body (7) consists of non-magnetic material. In the case of such an ion-beam source, the intensity of the ion beam can be increased by compensating for the intrinsic space charge of the ion beam, and an increase in the ionisation level of the working medium can thus be achieved.