The anode means of a Hall accelerator with a main discharge area has coaxial cylindrical electrodes aligned with the longitudinal axis of the main discharge area and an auxiliary electromagnet surrounding the electrodes, and an electric field is applied across the cylindrical electrodes while the auxiliary electromagnet produces an axial magnetic field therebetween so that a preionization discharge area is formed in communication with the main discharge area.

A cold-cathode ion source with a closed-loop ion-emitting slit which is provided with means for generating a cyclically-variable, e.g., alternating or pulsating electric or magnetic field in an anode-cathode space. These means may be made in the form of an alternating-voltage generator which generates alternating voltage on one of the cathode parts that form the ion-emitting slit, whereas the other slit-forming part is grounded. The alternating voltage deviates the ion beam in the slit with the same frequency of the alternating voltage. In accordance with another embodiment, the aforementioned means may be an electromagnetic coil which generates a magnetic field which passes through the ion-emitting slit, thus acting on the condition of the spatial-charge formation and, hence, on concentration of ions in the ion beam. The cold-cathode ion source may be of any type, i.e., with the ion beam emitted in the direction perpendicular to the direction of drift of electrons in the ion-emitting slit or with the direction of emission of the beam which coincides with the direction of electron drift.

The invention provides a multiple-cell ion-beam source in which magnetic poles of all adjacent cells have alternating polarities, i.e., the cells arranged in a single row from the center to the periphery of the cathode plate have polarities in the order of N-S-N-S-N . . . , etc. As a result, the direction of magnetic lines of forces in the aforementioned rows alternates, and therefore the magnetic flux is not accumulated towards the center. This means that the source of such a construction does not have dimensional limitations and ensures uniform distribution of the ion-beam current density over the entire surface of the object. Intensity of the magnetic field for each individual cell can be controlled individually. This allows adjustment in the distribution of the ion-beam current density over the surface of the object.

A universal cold-cathode type ion source with a closed-loop electron drifting source and with an ion-beam propagation direction perpendicular to the plane of electron drifting is intended for uniformly treating stationary or moveable objects with such processes as cleaning, activation, polishing, thin-film coating, or etching. The ion source of the invention allows adjustment of beam parameters and configurations and has an ion emitting slit of an adjustable geometry. In one embodiment, the adjustment is carried out by changing the width of the slit by shifting moveable parts of the cathode in the direction perpendicular to the direction of the ion beam. In another embodiment the slit configuration is adjusted by shifting a moveable part of the cathode in the direction of the beam propagation. The invention also provides a method for adjusting the shape and configuration of the ion beam with respect to the object to be treated. The adjustment can be performed during the operation of the ion beam while observing the beam through a sealed transparent window of the vacuum chamber.

The ion source of the invention emits ion beams radially inwardly or radially outwardly from the entire periphery of the closed-loop ion-emitting slit. In one embodiment, a tubular or oval-shaped hollow body, which also functions as a cathode, contains a similarly-shaped concentric anode spaced from the inner walls of the cathode at a distance required to form an ion-generating and accelerating space. The cathode has a continuous ion-emitting slit which is aligned with the position of the anode and is concentric thereto. A magnetic-field generation means is located inside the ring-shaped anode. When the ion source is energized by inducing an magnetic field, connecting the anode to a positive pole of the electric power supply unit, the cathode to a negative pole of the power supply unit, and supplying a working medium into the hollow housing, the electrons begin to drift in the annular space between the anode and cathode in the same direction in which the ions are emitted from the annular slit. By rearranging positions of magnet, anode, and cathode, it is possible to provide emission of ions in the inward or outward direction for treating outer or inner surfaces of tubular objects.