Abstract: A plasma source is described, comprising a discharge chamber (1) bounded by a base wall (5) and by a lateral wall (3), a system (7) for the admission of gas into said discharge chamber, a system of electrodes (13, 15) which are associated with said discharge chamber (1) and which are connected to a radio-frequency generator (17), and which apply an oscillating electric field within the discharge chamber, and means (9, 11) for generating a static magnetic field in said discharge chamber. Coaxially with said discharge chamber (1) there are disposed a first and a second electrode (15; 13; 13X), at least one of which has an annular extent and is disposed in an intermediate position along the axial extent of the discharge chamber, said two electrodes (15; 13; 13X) being connected to two poles of the radio-frequency generator.

Abstract: In a device for ion generation, the ionization chamber is characterized by walls coated with a material with a high coefficient of secondary emission, such as a suitable glass; this enables the energy yield and mass yield of the device to be improved with respect to known techniques. (FIG.

Abstract: An innovative method is proposed for the production of ion extraction grids, comprising the stages of:disposing a plurality of wires or metallic filaments in a lattice structure;coating said structure with a layer of boron.The coating with boron may take place by thermal reduction of boron trichloride in a hydrogen atmosphere. This makes it possible to produce grids at low cost and with high resistance to sputtering, suitable for use for the extraction, focusing and acceleration of the beam in ion sources for industrial and space applications.

Abstract: A technique is described for the production of manufactured articles of composite material of large thickness, the matrix of which is composed of polymerizable resins, using electron beams. To achieve the polymerization of the matrix, it is proposed to induce the adhesion of the resin of a layer (1) of already polymerized material with the resin of a second layer (3) to be polymerized by irradiating the second layer and the zone of adhesion between the first and the second layer with electron beams (F) of appropriate energy. The method can also be used for the welding of a plurality of layers or portions of already polymerized material. This permits the polymerization of matrices of such a thickness as not to be penetrated in a single phase by electron beams of limited energy. The treatment by successive phases performs the polymerization of the resin matrix in a manner equivalent to a simultaneous treatment over the entire thickness.

Abstract: A hollow cylinder (3) of suitable material (the cathode) and one or more anodes (5, 7) of suitable shape and dimensions permits the generation of high-density plasma capable of being used particularly (but not exclusively) for applications in space. The plasma is produced by an electrical discharge in a gas which flows in the device through the cathode (3) and suitable orifices (8, 27) formed in the anodes (5, 7) in order to create a pressure difference between the cathode cavity (3C) in which the discharge is to be initiated and the exterior of the device. The discharge is initiated in the first place between the hollow cathode (3) and the first anode (5) and is then transmitted to the following anodes. The cathode (3), unlike the usual hot cathodes, not only does not have a filament to heat it to a suitable temperature before the initiation of the discharge, but can operate even if kept suitably cold.

Abstract: An ion engine for the generation of primary plasma by discharge in a gas wherein the discharge is obtained by the simultaneous use of a magnetic conditioning and confinement field and an electromagnetic field. The latter being at a frequency such that the cyclotron resonance effect of the electrons in the gas can be exploited. The engine generates a static magnetic field and generates and applies an electromagnetic field at cyclotron frequency. By using the cyclotron resonance effect, it is possible to improve the processes of plasma generation and the processes of ion beam extraction by the use of an optimized system of grids made of refractory material. These processes are optimized to match the differences in the operating conditions acting on the intensity of the magnetic field.