Abstract: The disclosure relates to linear proton accelerators. A proton accelerator is made by using travelling waves with magnetic coupling to accelerate the protons in forward or backward mode and in fundamental or harmonic mode. In particular, an accelerator for medical use, giving energy of 250 MeV, uses three accelerator structures positioned in series and working with travelling waves of the forward, harmonic mode type for a first structure, of the backward harmonic type for a second structure and of the backward fundamental mode type for a third structure. Furthermore, the microwave energy at 3,000 megahertz is given by a single klystron. This results in a considerably reduced length of the accelerator and a cost that makes it capable of being used for therapeutic applications.

Abstract: Good bunching and high electron capture efficiency of a first resonant cavity of an accelerator are combined with the self-focusing properties of said cavity associated with a following second cavity by modifying the law of the modulus of the electric field set up within said cavity, the amplitude of said field being greater within a first portion of the cavity than within a second portion. It is shown that the electrons are thus naturally bunched within the first portion of the cavity. In the second portion of the cavity, they are than subjected to acceleration and then to uniform focusing which includes entry into the following cavity. The result thereby achieved is to increase the capture efficiency and electron density of the beam which is accelerated from a low-voltage electron gun.

Abstract: A self focusing linear charged particle accelerating structure is provided which avoids the radial defocusing effect of the particle beam, more particularly at the outlet of a first accelerating cavity which this structure comprises. Said first accelerating cavity comprises an inlet face and an outlet face which are spaced apart by a distance formed by an accelerating length plus an additional length intended to delay the arrival of the particles at said outlet face.

Abstract: An achromatic magnetic deflection device for deflecting by an angle .phi. between .pi. and 2.pi. a beam of charged accelerated particles having different momentum. This device comprises an electromagnet provided with pole pieces delimiting three contiguous sectors, the whole of these sectors, having an axis of symmetry XX, presenting flat input E and output S faces and common faces F.sub.1 and F.sub.2 in an arc of a circle, the position, the radius of curvature of these faces F.sub.1, F.sub.2 as well as the value of the magnetic induction in the sectors being chosen so that the different paths are substantially orthogonal both to faces F.sub.1, F.sub.2 and to axis XX.

Abstract: Magnetic system making it possible to obtain from a pulsed electron beam supplying bunches of electrons of density d.sub.o, a pulsed beam formed from electron groups of density k d.sub.o, said result being obtained by converting the variation of the momentum of the electrons emitted during the time .DELTA. t of the pulse into a length variation of the paths of said electrons, resulting in regrouping or rearrangement of the electrons within the bunch. This magnetic system has at least one electromagnet equipped with several pairs of pole pieces A, B, D defining a succession of air gaps in which are created, by means of at least one annular coil disposed therein, magnetic fields of different values.

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: Apparatus for irradiating the two opposite faces of a target by means of a scanning beam and comprising a magnetic deflection system formed by an electromagnet provided with two pole pieces disposed downstream of the target to be irradiated, the length of the pole pieces corresponding to the amplitude of the scanning beam in such a way that, if .theta.=.theta..sub.1 +.theta..sub.2 is the total scanning angle, the scanning beam of angle .theta..sub.1 impinges on one face of the target, while the scanning beam of angle .theta..sub.2 =.theta.-.theta..sub.1 is deflected in the magnetic deflection system and irradiates the other face, the polepieces having a face, so-called useful face, facing the other face of the target and comprising several sections with different curvatures for obtaining a reflected beam substantially perpendicular to this other face of the target.

Abstract: An apparatus for treating waste-waters and sludges and using an irradiation beam of accelerated electrons, comprises a treatment circuit c equipped with valves, an electromagnetic regulator providing a constant flow of the fluid to be treated by the irradiation beam, systems for controlling the flow of fluid and for controlling the characteristics of the irradiation beams, a microprocessor associated with the flow control systems for controlling at least the automatic closure of a shut-off valve and the opening of a purge valve.

Abstract: A compact accelerating structure comprises an accelerating section and a complementary section which may be used as a bunching section and/or a preaccelerating section, this complementary section being constituted by a first cavity and a second cavity joined to one another and electromagnetically coupled with one another in a direct manner, the second cavity, which is adjacent to the accelerating section, having a length L and being electromagnetically coupled to the first cavity and to the accelerating section in such a manner that the electromagnetic accelerating field is zero in this second cavity.

Abstract: An accelerating structure for a linear particle accelerator operating in the progressive wave mode or in the stationary wave mode and comprising at least one accelerating section and a complementary bunching or pre-accelerating section formed by a resonant cavity C of the "reentrant" type magnetically coupled with the first cavity of the accelerating section by means of a coupling iris, the cavity C having a length L=(2m+1).lambda..sub.o/4 and the distance D separating the interaction spaces of the cavity C and the first cavity of the accelerating section being equal to D=(2k+n/2+.alpha.).pi..beta..lambda..sub.o, with O.ltoreq..alpha..ltoreq.1/4, n and k being integers, .beta. being the reduced velocity v/c of the particles and .lambda..sub.o being the operating wave length of the accelerator.

Abstract: A particle accelerator for obtaining high energy particle beams, comprises an accelerating structure S.sub.A, one mirror or two mirrors constituted with magnetic achromatic and stigmatic deviators and a source K of particles located at the entry of the accelerating structure S.sub.A and having an annular shape allowing the accelerated particles having passed twice through the accelerating structure S.sub.A to cross the source K, the axis of the source K being coincidental with the axis of the accelerating stucture S.sub.A. Magnetic fields are determined in such a manner that the mirrors totally reflect the particles having a predetermined energy level and totally transmit the particles having an energy level higher than this predetermined energy level.