Proel Tecnologie S.p.a.

Proel Technologie S.p.a.

Fabbrica Italiana Magneti Marelli, S.p.a.

Valfivre S.p.a.

Gianfranco Cirri

Giovanni Fidanzati

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. 2)

Ion generator with ionization chamber constructed from or coated with

The equipment for measuring on earth the thrust of thrusters for use in space comprises a balance (1) and a measuring means (11) which is associated with the balance in order to measure the thrust exerted by the thruster (P). The balance (1) is provided with a target (13) at which the exhaust jet from the thruster (P) is directed, whereas the thruster is mechanically free from the structure of the balance and the measuring means (11) measures the force applied to the balance in order to balance the thrust exerted on the balance by the jet from the thruster. (FIG. 3)

Device and method for measuring on earth the thrust of thrusters for use

In the discharge chamber (21) of a device for generating plasma, used in the space sector for ion propulsion or for the discharging of satellites and in applications on the ground, suitable ionizing radiation sources (47) are provided, capable of improving the performance of said device. The radiation emitted by the sources creates constant ionization of the gas with advantages both during the preionization phase, i.e. starting of the device, and during the operating phase, standardizing the performance thereof in particular in terms of continuity and regularity of operation.

Plasma generator and associated ionization method

The cathode of an electron gun is connected to the body of a space vehicle, performing an automatic limitation (or neutralization) of the negative potential (measured with respect to the physical entity toward which the electron beam is directed, i.e. the anode (A) of the gun, whether this be the environment in which the gun is immersed or a particular object such as a second space vehicle) which the body may assume in the absence of the connection referred to. The aforementioned negative potential is limited or neutralized by means of the extraction of negative charges emitted from the gun (K-E) in the form of an electron beam under appropriate conditions of vacuum. The gun comprises a cathode (K) to be connected to the body (C), at least one accelerating electrode (E), an accelerating voltage generator (G) and a generator (R) for heating the cathode.

Electron gun device for controlling the potential of a body in space

An innovative method is proposed for the production of ion extraction grids, comprising the stages of:

Method for the production of extraction grids for ion generation and

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.

Method for the production of manufactured articles of resin or composite

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.

Cyclotron resonance ion engine

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.

Device with unheated hollow cathode for the dynamic generation of plasma

An electron gun and a high tension switch permits the achievement of high-power electron beams which are ON-OFF modulated by DC up to frequencies exceeding kHz. The electron gun has a cathode, at least two accelerating electrodes, a cathode heater, and a possible focussing system. The or each accelerating voltage, generated by any source, which may in the case of space applications also be a tether, is applied between accelerating electrodes and cathode, with the exception of an appropriate accelerating electrode to which there is applied, by of the switch, alternately its accelerating voltage or the same voltage as that of the cathode, obtaining an ON-OFF modulation of the electron beam emitted by the gun.

Device for generating an on-off modulation electron beam

A process and apparatus for increasing the pulse repetition frequency in a laser is disclosed. The laser includes first and second series connected discharge tubes, a supply unit for applying energy to the discharge tubes and a pulse generator for controlling the discharge of the discharge tubes. The discharge tubes are alternately discharged such that one of the tubes is charging as the other of the tubes is discharging. In this manner, the maximum pulse frequency of the laser is twice the maximum pulse repetition frequency of each of the individual discharge tubes.

Process for increasing the pulse repetition frequency in a laser

A process for the fabrication of thermistors is described. Conductive wires are positioned in a spaced fashion and are aligned so as to intersect one another. The wires are maintained in the above alignment and placed into a reaction chamber or other suitable environment in which chemical vapor deposition of a semiconductor material by a pyrolysis technique is produced. The temperature of the reaction chamber is preferably just below the temperature level needed to produce the vapor deposition. Electric current is preferably passed through the conductors causing them to heat at the region of the intersections to a level sufficient to induce vapor deposition. The semiconductor material is caused to be deposited upon the conductors in the region of the intersection and is continued until the semiconductor material substantially completely surrounds both of the wires in the region of the intersection so as to mechanically and electrically join the wires. The growth is continued until the thermistor of the desired characteristics is developed. Thereafter, two adjacent leads are removed leaving the remaining two leads projecting from the semiconductor material for use in coupling the thermistor to electrical circuits. The process when completed substantially provides a thermistor device which is ready for use without the need for performing additional steps of providing electrical terminations. The nature of the process also lends itself advantageously for producing thermistors on a large mass production scale.

Process of thermistor manufacture

An accelerometer sensor comprising two vertically disposed tubular passages communicating at their bottom; the passages and the connection therebetween being partially filled with a conductive liquid; an electrical resistor in each passage; a conductor communicating into the liquid; an electrical circuit for detecting the resistance unbalance in the resistors, due to the shifting liquid caused by acceleration.

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Florence, Italy

Gianfranco Cirri