Abstract: This gun comprises a cathode K, a grid G, and an anode A between which the applied voltages are radio-frequency voltages. The cathode is disposed on the central conductor of a coaxial cavity, facing said grid terminating said cavity. Said cavity is terminated at the other end by a short-circuit and includes a coaxial branch line so as to resonate at two frequencies F.sub.1 and F.sub.2 multiple of f.sub.0, whose beating induces a radio-frequency grid-cathode voltage. Said grid terminates another coaxial cavity whose central conductor is hollow and whose end facing said grid forms the anode. said other coaxial cavity resonator is excited and resonates at a frequency F.sub.0 multiple of f.sub.0, which induces a radio-frequency anode-grid voltage.A proper selection of the frequencies F.sub.0, F.sub.1, F.sub.2 allows to obtain electrons bunches of very short duration.

Abstract: The disclosure relates to an undulator, namely a device generating a transverse magnetic field polarized alternatively North-South and South-North along the path of an electron beam and enabling the direct conversion, in a free electron laser, of a part of the energy of a beam of relativistic electrons into light energy. The undulator comprises a conductor forming, along the path of the electron beam, undulations that wholly or partially induce the transverse magnetic field. To increase the light efficiency, it consists in providing for auxiliary current bypass connectors on said conductor. These auxiliary connectors enable the modulation of the transverse magnetic field as a function of the changing characteristics of the high frequency electrical field which increases during the arrival of a packet of electrons in the optical cavity of the laser owing to the energy yielded by these electrons.

Abstract: The invention concerns a power modulator provided with a transformer. This transformer having a high transformation ratio receives a low voltage impulse and transforms it into a high voltage impulse directly applicable on a high frequency or hyperfrequency tube in order to create a powerful impulse magnetic field. The transformer is particularized by the realization of its primary composed of a plurality of primary windings, all of which are connected in parallel and which, put end to end, extend along the entire lengths of the secondary. They are wound furthermore around the secondary and not inside it.

Abstract: The invention provides a self-focusing cavity for accelerating charged particles, intended to form the first or only cavity of a linear accelerating structure; this structure accelerating a charged particle beam along an axis merging with a longitudinal axis of this structure. The cavity of the invention comprises an input wall sloping with respect to said longitudinal axis so as to form a surface of revolution providing a charged particle focusing effect.

Abstract: An irradiation head permitting the positioning of the area to be treated and the checking of this position. This irradiation head, which is disposed downstream of the neutron target, is provided which a turret carried by a supporting plate and which can rotate about an axis zz perpendicular to said plate. The supporting plate has a central opening A of axis ZZ coinciding with the axis of the useful neutron beam and the axis of the collimator. The turret has three openings a.sub.1, a.sub.2, a.sub.3 which can successively face the opening A in accordance with the axis ZZ. Two of the openings a.sub.1, a.sub.2 are respectively associated with a light source S.sub.1 and an X-ray source S.sub.2 emitting beams of mean paths f.sub.1 and f.sub.2 equidistant with respect to axis zz, these beams being respectively designed for the positioning of the area to be treated and the checking of this position.

Abstract: The particle-accelerating device comprises a charged-particle source, a linear accelerating structure formed by a series of accelerating resonant cavities, an electromagnetic wave generator for emitting a signal to be injected into at least one of the resonant cavities. Means are provided for applying a pulsed high voltage to the particle source and for scanning a target with the pulsed beam of accelerated particles. The electromagnetic wave generator comprises a thermionic tube having a cathode, an anode and at least one grid. At least one of the resonant cavities is electromagnetically coupled to the grid-anode space of the tube.

Abstract: Magnetic mirror enabling a beam F of charged particles to be reflected along its incident path whatever the value W of the momentum of said particles. This magnetic mirror includes a first magnetic deflector having polepieces of circular shape, a second and a third magnetic deflector provided respectively with pairs of polepieces arranged symmetrically with regard to an axis XX coinciding with the mean incident path of the beam F, the entry and exit face of these polepieces being determined in such a way that the beam F emerging from the second magnetic deflector is perpendicular to the symmetry axis of the mirror and that the vertical divergence of the beam is compensated.

Abstract: This device makes it possible to achieve upon a target of predetermined position, the simultaneous focusing of a beam of accelerated particles, in two mutually perpendicular planes, this, whatever the energies of said particles. The device comprises two electromagnets E.sub.1 and E.sub.2 whose entry and exit faces are parallel with one another, and a third electromagnet E.sub.3 whose entry and exit faces are at an angle .gamma.. Relationships are given to determine the different parameters defining the dimensions and positions of the electromagnets in relation to one another being linked by determinate relationships. The device can be utilized in physical and biological researches, as well as in medical irradiation units.