Acceleration of Charged Particles in an Annular Cavity Resonator with Magnetic Trajectory Control
Abstract Generated abstract
This paper proposes using the accelerating chamber itself as an annular cavity resonator or waveguide for charged-particle acceleration, rather than installing a separate cavity resonator in the chamber. It outlines possible excitation schemes, including standing waves, traveling waves, and a high-frequency field across a gap in a conducting layer on the chamber walls, and argues that such arrangements could simplify construction while allowing high accelerating fields. The authors emphasize the use of electric field modes, specifically E01 in a ring waveguide and E010 in a ring cavity resonator, with magnetic control of particle trajectories to maintain the required orbit radius during acceleration.
Full Text
ACCELERATION OF CHARGED PARTICLES IN AN ANNULAR CAVITY RESONATOR WITH MAGNETIC TRAJECTORY CONTROL
A. A. VOROBYOV and G. V. KRIVOSHEKOV
Field systems (cavity resonators) in which an electromagnetic field is excited in one way or another may be regarded as guides for electromagnetic waves used for accelerating particles [1].
In synchrotrons, the electric field in the gap of a quarter-wave cavity resonator is used as the accelerating interval. The manufacture of this accelerating element and its installation in the accelerating chamber present certain difficulties.
It is proposed, instead of a separate cavity resonator introduced into the accelerating chamber, to excite electromagnetic oscillations in the accelerating chamber itself. The cavity resonator or waveguide will be formed by a conducting layer covering the inner walls of the accelerating chamber. In this case three variants are possible: 1) excitation of standing waves, 2) excitation of traveling waves, 3) excitation of a high-frequency field in the gap of the conducting layer. In the latter case (Fig. 1) the accelerating chamber, coated with a conducting layer, is regarded as
Diagram labels: accelerating chamber; conducting layer; gap; high-frequency voltage.
Fig. 1
an oscillatory circuit with “concentrated” constants (the gap is the capacitance, the entire accelerating chamber coated with a conducting layer is the inductance),
In all variants of excitation there is a considerable advantage over the existing methods of acceleration by means of a separate volume resonator introduced into the accelerating chamber, or by using a sector of the accelerating chamber as a quarter-wave resonator.
First, the separately constructed volume resonator, which is difficult to design, is eliminated; second, accelerating fields of high intensity can be created. The fields excited in the accelerating chamber, used as a volume resonator or waveguide, must have a longitudinal component of the electric-field intensity along the axis of the chamber. To obtain particle trajectories of constant radius, as in synchrotrons of the usual design, the magnetic-field induction must increase synchronously with the increase in particle velocity. Proposals to use “coiled waveguides” for the purpose of accelerating charged particles have been made earlier. However, the proposals made envisaged acceleration by means of the fundamental wave of magnetic type, i.e., \(H_{01}\). In such a case the charged particles move in the chamber from wall to wall; for accelerating a charged particle moving rectilinearly, the particles must successively pass through several cross sections of the waveguide. In this case the waveguide is arranged in a plane spiral.
We propose to use, for accelerating particles in a ring waveguide, the fundamental electric wave of type \(E_{01}\), and, for acceleration in a ring volume resonator, a field structure of type \(E_{010}\). Control of the trajectory of the accelerated particles is effected by means of a magnetic field.
Closed curvilinear waveguides can be used for accelerating charged particles without a controlling magnetic field, by controlling the trajectory of the electrons upon their reflection from specially installed reflectors or by using reflection of the electromagnetic wave from the walls of the waveguide.
LITERATURE
- Veksler, A. A. Accelerators of Charged Particles. GÉI, p. 220, 1949.