GB1033597A - Circular particle accelerators - Google Patents

Abstract

1,033,597. Magnetic induction accelerators. CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE. June 11, 1964 [June 14, 1963], No. 24329/64. Heading H1D. A circular particle accelerator, e.g. a betatron, has in addition to the windings 2 for producing the guiding field, a winding 6, as shown made up of square turns connected in series, for producing an azimuthal focusing field and means, such as electrode coatings 7, 7<SP>1</SP>, for producing a temporary transverse deflecting field at the moment of injection of the particles. The arrangement is such that particles injected during several revolutions are accepted without loss to the walls or to the gun structure 4 located at the periphery of the vacuum chamber. The electrodes 7, 7<SP>1</SP> are disposed obliquely to the central plane of the chamber or a third, neutral, electrode may be provided to prevent axial slip by the particle orbits. In another embodiment the particle deflecting field is induced by rapid variation of the azimuthal field. In order that the induced field may be zero at the centre of the vacuum chamber the turns of the azimuthal field winding approximate to semi-elliptical form; in practice they are polygonal and the turns are connected in parallel. The gun is arranged to inject the particules either tangentially to a peripheral orbit or predominantly radially with a small tangential component. An electrostatic screen formed by an inner wall coating is provided in the second embodiment. The screen may be subdivided to enable the setting up of a radial electrostatic field varying in proportion to the azimuthal field to compensate for axial slip of the particle orbits due to non- uniformity of the azimuthal field. The invention is described in connection with an aircored betratron.