PLASMA ION SOURCE Russian patent published in 2009 - IPC H01J3/04 H01J37/08 

FIELD: physics.

SUBSTANCE: plasma ion source has a cathode chamber (1), which is fitted with a gas inlet pipe (2). On the outer wall of the cathode chamber (1) there are pipes (10) for a forced cooling system. A hollow anode (3) forms the anode chamber (4) of the ion source. The emission electrode (11) of the ion extraction system is placed in the outlet opening of the anode chamber (4). Between the cathode and anode chambers there is an additional electrode (5), with holes (9). Diametre d of the holes (9) satisfies the condition: 0.1 mm<d<1 mm. On the surface of the additional electrode (5) there are projections with the shape of a flattened cone, in which holes (9) are made. The projections are directed towards the cathode chamber (1). The anode chamber (4) has an earthed case (7), which is electrically connected to the additional electrode (5). The magnet system has a source of magnetomotive force, which is made in form of an electromagnetic coil (15), fitted coaxially with the additional electrode (5). The flux density vector of the formed magnetic field has an essentially axial direction in the cathode and anode chambers. Value of magnetic flux density B in the axial direction near the holes (9) lies in the range from 2 to 15 mT. Magnetic flux density falls in the axial direction from the additional electrode (5) to the emission electrode (11) and from additional electrode (9) to the end wall of the cathode chamber (1) to a value not greater than 0.6 B. Configuration of the magnetic field, formed in the cathode and anode chambers, choice of magnetic flux density value in the holes (9), as well as choice of the diametre of holes (9) in accordance with given conditions allows for generating intense ion beams with a large diametre using the plasma ion source.

EFFECT: high uniformity of ion current density in the section of the extracted beam.

9 cl, 4 dwg