RU1653525C - Accelerator of charged particles - Google Patents

Abstract

FIELD: acceleration equipment. SUBSTANCE: invention refers to generation of heavy-current fluxes of accelerated particles with energy exceeding 1 MeV. Accelerator of charged particles has power supply source 1, inductive accumulator 2, plasma current interrupter composed of two coaxial electrodes - cathode and anode, plasma guns 6 and spiral 5 coaxial to electrodes coupled in series. Spiral 5 is placed between plasma guns 6 and outer electrode of plasma interrupter and is manufactured from hollow conductor which houses power supply cables of plasma guns. Average radius of spiral, number of turns and number of starts are chosen in compliance with expressions given in description of invention. EFFECT: increased accelerating voltage and efficiency. 2 dwg

Description

 The invention relates to accelerator technology and can be used to obtain high-current flows of accelerated particles with an energy of more than 1 MeV.

 The aim of the invention is to increase the accelerating voltage and efficiency of the accelerator.

 Figures 1 and 2 show an accelerator diagram in two projections.

 The accelerator contains a power source 1, an inductive storage 2, an insulator 3, an external electrode - a vacuum chamber 4, a spiral 5, plasma guns 6, a high-voltage electrode 7.

 Source 1, drive 2, high-voltage electrode 7, a gap filled by plasma between the electrode 7 and plasma guns 6, i.e. plasma current choppers (PPT), the spiral 5 and the outer electrode 4 form a closed electrical circuit. Plasma guns 6 and electrode 7 are the cathode and anode of the PPT. The insulator 3 serves as a support for the electrode 7. The plasma guns 6 are shifted along the axis relative to the spiral 5 by a length approximately equal to the cathode-anode gap of the PPT. The plasma guns 6 are fed through cables laid inside the hollow conductor (tube) from which the spiral 5 is made.

 The accelerator works as follows.

Using plasma guns 6 fill the vacuum gap PPT plasma and then turn on the power source 1. A current I _о begins to flow in the circuit, and magnetic field energy is stored in the inductive storage 2.

The charging mode is carried out, the resistance of the PMT is small. At the same time, an azimuthal magnetic field H _{φ is created} around the high-voltage electrode 7 and a longitudinal field H _z inside the spiral.

H_кр=

(γ²-1)^1/2 (2) где Н_кр - критическая величина магнитного поля, определяемая эффективным зазором катод-анод d_эф и напряжением на зазоре, точнее, соответствующим ему релятивистским фактором γ .When the current reaches a critical value, a double layer forms at the cathode — a rupture of the plasma, which, as a result of its erosion, expands toward the anode. The resistance of the PPT increases sharply - the acceleration mode is carried out. The azimuthal field leads to the drift of electrons along the axis in crossed E x H fields and the removal of plasma in this direction by a length approximately equal to the cathode-anode gap of the PPT. In order for the plasma rupture to occur in the region of the longitudinal field H ₂ (under the helix), the plasma guns 6 are shifted relative to the helix 5 in the direction of the power supply 1. For the same purpose, the spiral can be made extended along the axis. The presence of a spiral will lead to a significant increase in the rate of plasma erosion, i.e. to increase the efficiency of the accelerator if the longitudinal field H _z created by it at the cathode exceeds the azimuthal field H _φ , i.e., if near the cathode, where a double layer is formed, the condition
H _z > H _φ (1)
The magnitude of the resulting voltage can be estimated from the condition
H _z

H _cr =

(γ ² -1) ^1/2 (2) where H _cr is the critical value of the magnetic field, determined by the effective cathode-anode gap d _eff and the voltage across the gap, more precisely, the corresponding relativistic factor γ.

H_φ=

(3)
если r_к

r_cp , то
H_z=

(4)
Таким образом, как следует из (3) и (4), условие (1) требует выполнения одного (более слабого из неравенств):
N

мин

;

- 1

(5)
При этом отпадают трудности с заполнением зазора ППТ плазмой, поскольку продольное поле Н_z возникает после того, как зазор ППТ уже заполнен плазмой. Это позволяет оптимизировать параметры плазменных пушек (т.е. параметры плазмы в ППТ) и таким образом увеличить эффективность работы ППТ.Condition (1) leads to the following relationship between the number of turns of the spiral N, its average radius r _sr and the radius of the cathode r _to :
if r _k << r _cf then
H

H _φ =

(3)
if r _to

r _cp then
H _z =

(4)
Thus, as follows from (3) and (4), condition (1) requires the fulfillment of one (the weaker of the inequalities):
N

min

;

- 1

(5)
In this case, there is no difficulty in filling the PPT gap with plasma, since the longitudinal field H _z arises after the PPT gap is already filled with plasma. This allows you to optimize the parameters of plasma guns (i.e., plasma parameters in the PMT) and thus increase the efficiency of the PMT.

The number of turns N is defined as the ratio of the length of the spiral conductor to the circumference. For N <1, in order to obtain an azimuthally uniform field H _{z, the} helix is multi-start, the number of entries is n> 1 / N.

 Thus, such a design of the accelerator allows not only to create the magnetic field necessary for electron cutoff and increase the voltage in the interelectrode gap of the PPT, but also to provide the opportunity to optimize the plasma parameters in the PPT and thus increase the efficiency of the accelerator.

 Due to the restrictions on the density of the rupture current, high-current accelerators based on PPT are large in size, therefore, the creation of a magnetic field in an interelectrode gap from an external source requires large energy expenditures that exceed the energy expenditures for charging an inductive storage ring, which makes the use of a spiral economically feasible as well.

 This scheme allows you to increase the voltage and efficiency of the accelerator more than 1., 5 times.

Claims (1)

CHARGED PARTICLE ACCELERATOR, comprising a power supply connected in series, an inductive storage device and a plasma current chopper, including two coaxial electrodes - a cathode and anode, plasma guns and a spiral coaxial with the electrodes, characterized in that, in order to increase the accelerating voltage and the efficiency of the accelerator, the spiral is connected between the plasma guns and the external electrode of the plasma chopper and is made of a hollow conductor, inside which the power cables of the plasma guns are located, with the average radius spiral r _{with p} , m, the number of turns N and the number of entries n are selected according to the expressions

where r _to is the radius of the cathode, m

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