SU741347A1 - Device for shaping pulsed electron beam - Google Patents

Description

The invention is attributed to accelerator technology and can be used, for example, in high-current induction accelerators (LIAs) for energy of five ten MeV.

A device using a source of particles, a permanent magnet located on the drift section of the accelerator and deflecting particles with 10 different energies at given angles, and a highly stabilized DC source feeding the winding of the deflecting magnet 11 is known. To increase the uniformity of the deflected magnetic field in the passage of the beam, the pole of the magnetic circuit in some cases is shaped as semi-ellipses separated by a slit, and sometimes the poles of the magnet are simultaneously conductive.

With the help of such a device it is possible to form monochromatic beams, the deviation of the short-circuit of the total spectrum is partial. titsy with a certain energy. 25

The disadvantage of this device is the bulkiness of the deflecting magnet, the large weight of its windings and magnetic circuit. The range of action for energy and deviation angles, i.e. Q range

adjusting such a magnet is usually small; in addition, due to the large inductance, a high-speed pulsed mode of operation is not feasible.

It is also known a device for generating a pulsed electron beam, containing a pulsed electron gun, a imi-cathode and a grounded anode, the source of accelerated voltage 21.

The disadvantage of this device is the existence of a finite value of the front durations and the occurring accelerated pulses (100-500 nil). The presence of particles with energy (0-0.9) E located at the front and in the fall limits the production of large average electron currents in LIA when using such a gun, since these particles will not be kept near the accelerator axis and will bombard and destroy the chamber. LIU

The aim of the invention is the monochromatization of the electron beam.

For this purpose, in a device containing a pulsed electron gun, having a cathode and a grounded anode, the source of accelerating voltage is made in the reader of an element that represents

two half-cylinders connected by an annular jumper with an outward-curved end on the cathode side, one of the opposite ends of the half-cylinders being grounded and the other connected to the additionally introduced source of pulse currents connected to the synchronizer also connected to the accelerating voltage source.

FIG. 1 schematically shows the proposed device; Fig.2Dia1telafl, illustrating the operation of the device. Here 1 is the source of pulsed voltage, 2 is the cathode of a pulsed electron gun, 3 and 4 are the lower and upper half-cylinders, 5 is a ring jumper, 6 is the bent end of the anode of the electron gun, 7 is the source of pulsed currents, 8 is a synchronizer.

The device works in the following way.

Two clock pulses from the synchronizer 8 simultaneously start the source 1 of the pulsed accelerating voltage and the first channel of the source 7 of the pulse currents. Electrons located at the front of the injected bunch and having non-nominal energy (0-0.9) fall into a pulsed transverse magnetic field produced by flow in semi-cylinders 3 and 4 and the ring jumper 5 of the current pulse from source 7 and despite the existing axial focusing constant a magnetic field is planted on these parts of the anode which are forcibly cooled

Simultaneously with the beginning of the flat top of the accelerating pulse (see Fig. 2), the first channel of the source of impulse currents ends in a steep downturn, and electrons with energy (0.9-1.0) E, cn. pass without interruption.

The action of the second channel of the source of pulsed currents begins with a steep front of the end of the flat top of the accelerating pulse by starting it from the synchronizer with the third sync pulse with delay +. regarding the first two. Electrons that are on the decay of the accelerator. impulse and having an energy of (0.90) Emvm, are removed from the acceleration process in the same way as photon pulses.

Calculations show that with an injection energy of (500–700) keV focusing a field of 300–500 Å, an electron current of up to 250 A, the amplitude of current pulses in a device with a cut length between hemispheres of 15–16 cm and a radius of 2.5–3 cm should be 90 -1000 And with the steepness of the front and

A / s

slept current pulses up to 5-10

in a manufactured device being developed as an injector for an LIA, as shown by tests, for deflection of particles with an energy of 310 keV at a cut length of 15 cm and a radius of 3 cm, the amplitude of the deflecting current pulses is 320 A. Focusing field is about 150 E. Duration of monochromatization pulses , corresponding to the duration of the front and decay of accelerating pulses, is 0.8 of the ISS, the duration of the front and spades are 2-4 NS.

The device is compact and allows to obtain electron beams with a high degree of monochromatization.

Claims (2)

1. Works of the All-Union Conference on Accelerators of Charged Particles. M., VINITI, 1970, Vol. 1, p. 2.Anatsky A.I. and others. Linear induction accelerator. 1A ,, Atomic Energy, 1966, T.21, Issue 6, p.439 (prototype).