JPS6376299A - Induction accelerator - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in guided accelerators.

Induction-type accelerators accelerate charged particle beams (hereinafter referred to as beams), such as pulsed electron beams and ion beams, passing through an acceleration tube maintained in a vacuum by applying an induction electric field. An example of accelerating an electron beam with an energy of IMeV to several tens of MeV was announced in the United States, and development is progressing in fields such as inertial fusion research and free electron laser amplifiers.

BACKGROUND ART FIG. 3 shows a conventional induction accelerator, in which (A) is a simplified sectional view for explanation and (0) is an equivalent circuit diagram. (2) is a cylindrical metal accelerator tube maintained in a vacuum, and a beam 2 guided by a magnetic field (not shown) passes through this accelerator tube l°.

By the operation of a pulse power source 1) consisting of a power source 3, a switch 4, a circuit impedance 5, etc., a part of the accelerating tube l, that is, an excitation coil, is formed by one winding of a ferromagnetic material 6 such as ferrite, amorphous, or silicon steel. When a voltage is applied between a and b of the acceleration tube 12, an electric field is applied to the magnetically insulated space 10 of the acceleration tube 1 due to a change in magnetic flux, and the beam is accelerated inductively. In other words, the excitation coil 12 corresponds to the primary coil of a transformer, and the voltage generated between c and d, which corresponds to the secondary coil, gives energy to the beam 2. In other words, the beam 2 is accelerated in an inductive manner.

The equivalent circuit of the accelerator shown in FIG. 3(A) is shown in FIG.
As an example of circuit impedance 5, take inductance 5,
The inductance C of the excitation coil 12 and the load 2' as an example of the beam 2 are shown. When the switch 4 is closed after charge is stored in the capacitor 3' by an element not shown, the charge in the capacitor 3' begins to be discharged to the inductances 5' and 6'. At this time, if the beam 2 is passing through, energy is given to the load 2', and after passing, the beam 2 is in an unloaded state.

Module A to module B, -----------
If multiple stages are installed, the acceleration voltage will increase by the number of installations.

Problem to be Solved by the Invention Just as the inductance 5' must be sufficiently small relative to the inductance 6' in order to effectively impart energy to the load 2', its impedance must be sufficiently small relative to the inductance 6'. must be sufficiently smaller than the impedance of

Generally, the pulse width of beam 2 is very short, 10 to 100 ns, so even if you try to give energy inductively,
It must have sufficient response characteristics to follow this. If the inductance of the inductance is the inductance, the impedance of the load 2' is expressed by Z, and the response characteristic to the load 2' is expressed by τ, then τ and □ are obtained.

In other words, in order to effectively give energy to a load 2' with a short pulse width, τ must be sufficiently smaller than the pulse width.For example, if Z=10Ω and the pulse width is 2
In the case of 0 ns, considering that the response time is 1/10 of the pulse width, τ≦2 ns. In other words, L must be 20 nH or less. Inductance exists in the circuit for transmitting pulses from the electric current, and even if you try to use coaxial lines, parallel plate lines, or multiple lines, there is a limit, and it is less than 2Q n 1) above. It is a very difficult technique to do. Therefore, with today's technology, it has not been possible to respond effectively and provide energy to a beam with low impedance or a beam with a short pulse width.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention inserts a capacitor with an appropriate capacitance in parallel with the load, temporarily stores energy in this capacitor from the pulse power supply, and then prevents the beam from passing. At times, it is an attempt to effectively give energy to the beam using a low-inductance circuit.The inside of a cylindrical metal accelerator tube is evacuated, a ferromagnetic material is wrapped around the outer circumference of the tube, and a pulse power source is connected. In an induction type accelerator that is provided with a l1lJvL coil and accelerates a beam by applying an electric field to a magnetically insulated space in the acceleration tube by changing the magnetic flux of the excitation coil, an induction type accelerator is provided with a capacitor in an insulated space directly connected to the excitation coil. The aim is to provide a shape accelerator.

Embodiment An embodiment of the inductive accelerator of the present invention shown in FIG. 1 will be described. The same figure (a) is a simplified cross-sectional view for explanation, the same figure (a)
) is an equivalent circuit diagram. Reference numeral 1 denotes a cylindrical metal acceleration tube kept in a vacuum, and a beam 2 guided by a magnetic field (not shown) passes through the acceleration tube 1. Ferrite, amorphous,
When a voltage is applied between a part of the accelerator tube 1 formed by one turn of a ferromagnetic material 6 such as silicon steel, that is, between a and b of the excitation coil 12, the magnetic insulating space of the accelerator tube 1 changes due to a change in magnetic flux. An electric field is applied to the beam 10 to inductively accelerate the beam 2. The insulating tubes 7 and 8 are each airtightly attached to a magnetic insulating space 10 provided directly connected to an excitation coil 12, which is a part of the accelerator tube 1, by a method not shown. The capacitor 9 is an airtight space filled with a liquid having a high dielectric constant, such as pure water or glycerin, c.
It is formed to have an appropriate capacitance value between d and d.

The equivalent circuit of the accelerator shown in FIG. 1(A) is as shown in FIG. 1(tl), and the capacitor 9 is inserted in parallel very close to the load 2'.

Next, to explain its operation with respect to the figure ((+)), when the switch 4 is closed, the charge stored in the capacitor 3' charges the capacitor 9' via the inductance 5'.The voltage of this capacitor 9' is When the beam 2 passes through C1d of the magnetic insulating space 10 at a sufficiently elevated stage, energy is effectively imparted to the load 2' by the capacitor 9'.

In the conventional technology, energy was given to the load 2' via the inductance 5, but in the present invention, since the capacitor 9 is installed near the inner diameter of the acceleration tube 1 through which the beam 2 passes, the energy up to the beam 2 is ) The inductance is extremely small and is almost negligible compared to the inductance S. Therefore, by storing electric charge in the capacitor 9', it has a very good responsiveness and has excellent performance in providing energy to the load 2'.

FIG. 2 shows another embodiment of the inductive accelerator of the present invention, and the effect can be obtained even if the capacitor 9 is a ceramic capacitor, a capacitor or a film capacitor, or an insulating plate or rod having a high dielectric constant. Although this embodiment shows a structure in which the inside of the excitation coil 12 is maintained in a vacuum state like the inside of the accelerating tube, it is also possible to attach the insulating tube 7 or both the insulating tube 7 and the insulating tube 8 shown in FIG. Therefore, another medium such as insulating oil may be placed in the insulating space 10 in order to improve the withstand voltage.

Effects of the Invention The inductive accelerator of the present invention has the following advantages: by providing a capacitor 9 in a conventional inductive accelerator, electric charge can be stored in the capacitor 9, and energy can be given to the beam 2 using an extremely low inductance circuit. It has excellent responsiveness, particularly for beams with short pulse widths and beams with low impedance, and is of great industrial and practical value.

[Brief explanation of the drawing]

Fig. 1 shows one embodiment of the inductive accelerator of the present invention, (a) is a simplified cross-sectional view for explanation, (b) is an equivalent circuit diagram, and Fig. 2 shows another embodiment of the inductive accelerator of the present invention. 3 shows a conventional induction accelerator, (a) is a simplified cross-sectional view for explanatory purposes, and (b) is an equivalent circuit diagram. 1: Accelerator tube 2: Beam 2': Load 3: Power supply 3':
Capacitor 4: Switch 5: Circuit impedance 5': Inductance 6: Ferromagnetic material 6': Inductance 7.8: Colored tube 9.9': Capacitor 10: Insulating space 1): Valse power supply 12: Excitation coil

Claims (3)

[Claims] (1) The inside of a cylindrical metal accelerator tube is evacuated, and an excitation coil made by winding a ferromagnetic material around the outside of the tube and connected to a pulse power source is provided, and due to changes in the magnetic flux of the excitation coil,
An induction accelerator that accelerates a beam by applying an electric field to a magnetically insulated space within the acceleration tube, characterized in that a capacitor is provided in the insulated space directly connected to the excitation coil. (2) The induction accelerator according to claim 1, wherein the dielectric material of the capacitor is water. (3) The induction accelerator according to claim 1, wherein the dielectric material of the capacitor is ceramic.