JPH0760760B2 - Induction accelerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to improvements in induction accelerators.

The induction type accelerator gives an induction electric field to a charged particle beam (hereinafter referred to as a beam) such as a pulsed electron beam or an ion beam that passes through an accelerating tube held in a vacuum to accelerate it. By increasing the number of electron beams having an energy of 1 MeV to several tens of MeV, an example was announced in the United States, and development is proceeding in fields such as inertial fusion research and free electron laser amplifiers.

2. Description of the Related Art FIG. 3 is a conventional induction type accelerator, in which (a) is a simplified sectional view for explanation and (b) is an equivalent circuit diagram. Reference numeral 1 denotes a cylindrical metallic acceleration tube held in a vacuum, and a beam 2 guided by a magnetic field (not shown) passes through the acceleration tube 1. A part of the accelerating tube 1 having a shape in which a ferromagnetic material 6 such as ferrite, amorphous, or silicon steel is wound once by the operation of the pulse power supply 11 composed of the power supply 3, the switch 4, the circuit impedance 5, etc., that is, the exciting coil 12 A, b
When a voltage is applied between the accelerating tube 1 and the change in magnetic flux,
An electric field is applied to the magnetically insulating space 10 in order to inductively accelerate the beam. In other words, the exciting coil 12 corresponds to the primary coil of the transformer, and the voltage generated between c and d corresponding to the secondary coil energizes the beam 2. That is, the beam 2 is accelerated inductively.

An equivalent circuit of the accelerator shown in FIG. 3 (a) is as shown in FIG. 3 (b). A capacitor 3'is an example of the power source 3, an inductance 5'is an example of the circuit impedance 5.
The inductance 6'of the exciting coil 12 and the load 2'as an example of the beam 2 are shown. When the switch 4 is closed after the charge is stored in the capacitor 3'by an element not shown, the discharge of the charge in the capacitor 3'in the inductances 5'and 6'begins. At this time, if the beam 2 is passing, energy is applied to the load 2 ', and after passing, the load is not applied. Module A to Module B ...
... If you install multiple stages, the acceleration voltage will increase by the number of installations.

Problems to be Solved by the Invention In order to effectively energize the load 2 ', the impedance of the load 5'must be the same as that of the inductance 5', as well as the inductance of the load 2 '. Must be well below the impedance.

Generally, the pulse width of the beam 2 is as short as 10 to 100 ns, so that even if an inductive energy is applied, it must have a sufficient response characteristic to follow the energy. If the inductance of the inductance 5 ′ is L, the impedance of the load 2 ′ is Z, and the response characteristic to the load 2 ′ is τ, Becomes

That is, in order to effectively apply energy to the load 2'having a short pulse width, τ must be made sufficiently smaller than the pulse width. For example, Z = 10Ω, pulse width is 20ns
, The response time is 1/10 of the pulse width, τ
2ns. That is, L must be 20 nH or less. The inductance 5'is present in the circuit for transmitting the pulse from the power source 3, and there is a limit even if efforts are made to use coaxial lines, parallel plate lines, or a plurality of these lines, and should be 20 nH or less. Is a very difficult technique. Therefore, it is difficult to effectively apply energy to a beam having a low impedance or a beam having a short pulse width by using the present technology.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention inserts a capacitor having an appropriate capacitance in parallel with a load, stores energy in the capacitor only from a pulse power supply, and passes the beam. At times, a low-inductance circuit is used to effectively impart energy to the beam. The inside of a cylindrical metal acceleration tube is evacuated, and a ferromagnetic material is wound around the outer circumference of the acceleration tube to connect a pulse power source. In an induction type accelerator in which an exciting coil is provided and a beam is accelerated by applying an electric field to the magnetic insulating space in the accelerating tube by a change in the magnetic flux of the exciting coil, an induction provided with a capacitor in an insulating space directly connected to the exciting coil. It is intended to provide a compact accelerator.

Embodiment An embodiment of the induction type accelerator of the present invention shown in FIG. 1 will be described. The figure (a) is a simplified sectional view for explanation, and the figure (b) is an equivalent circuit diagram. Reference numeral 1 denotes a cylindrical metallic acceleration tube held in a vacuum, and a beam 2 guided by a magnetic field (not shown) passes through the acceleration tube 1. Power supply 3,
By the operation of the pulse power supply 11 including the switch 4 and the circuit impedance 5, a part of the accelerating tube 1 having a shape in which a ferromagnetic material 6 such as ferrite, amorphous, and silicon steel is wound once, that is, a of the exciting coil 12, When a voltage is applied between points b, a change in magnetic flux gives an electric field to the magnetic insulating space 10 of the accelerating tube 1 to inductively accelerate the beam 2. The insulating cylinders 7 and 8 are airtightly mounted in a magnetic insulating space 10 directly connected to an exciting coil 12 which is a part of the acceleration tube 1 by a method not shown in the drawing.
The capacitor 9 is filled with a liquid having a high dielectric constant, such as pure water or glycerin, in a space hermetically held, and is formed to have an appropriate capacitance value between c and d.

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

Next, the operation will be described with reference to FIG. 9B. The electric charge stored in the capacitor 3'charges the capacitor 9'through the inductance 5'when the switch 4 is closed.
When the beam 2 passes between c and d of the magnetic insulating space 10 when the voltage of the capacitor 9'is sufficiently increased, that is, the energy is effectively supplied from the capacitor 9'to the load 2 '.

In the conventional technique, the load 2'via the inductance 5 '.
However, in the present invention, since the condenser 9 is mounted in the vicinity of the inner diameter of the accelerating tube 1 through which the beam 2 passes, the inductance up to the beam 2 is extremely small and can be almost ignored as compared with the inductance 5 '. It becomes a small value. Therefore, by storing the charge in the capacitor 9 ', the response is very good,
It has excellent performance capable of supplying energy to the load 2 '.

FIG. 2 shows another embodiment of the induction type accelerator according to the present invention, which is effective even if a ceramic capacitor, a paper or film capacitor, or an insulating plate or rod having a high dielectric constant is used as the capacitor 9. In this embodiment, the structure in which the exciting coil 12 is held in a vacuum state as in the accelerating tube is shown, but the insulating cylinder 7 or both the insulating cylinder 7 and the insulating cylinder 8 shown in FIG. 1 should be attached. Therefore, another medium such as insulating oil may be put in the insulating space 10 in order to improve the withstand voltage.

EFFECTS OF THE INVENTION In the induction accelerator of the present invention, by providing the capacitor 9 in the conventional induction accelerator, it is possible to store electric charge in the capacitor 9 and to give energy to the beam 2 with an extremely low inductance circuit. It is excellent in responsiveness, and particularly has an effect of obtaining excellent responsiveness to a beam having a short pulse width or a beam having a low impedance, and is of great industrial and practical value.

[Brief description of drawings]

FIG. 1 is an embodiment of the induction type accelerator of the present invention, (a) is a simplified sectional view for explanation, (b) is an equivalent circuit diagram, and FIG. 2 is another example of the induction type accelerator of the present invention. FIG. 3 is a simplified sectional view for explanation, FIG. 3 is a conventional induction type accelerator, (a) is a simplified sectional view for explanation, and (b) is an equivalent circuit diagram. 1: Accelerator, 2: Beam, 2 ': Load, 3: Power supply 3': Capacitor, 4: Switch 5: Circuit impedance, 5 ': Inductance 6: Ferromagnetic material, 6': Inductance 7, 8: Insulation cylinder , 9, 9 ': Capacitor 10: Insulation space, 11: Pulse power supply 12: Excitation coil

Claims (3)

[Claims] 1. A vacuum is applied to the inside of a cylindrical metal acceleration tube,
An exciting coil connected to a pulse power source by winding a ferromagnetic material around the outer circumference of the accelerating tube is provided, and an electric field is applied to a magnetic insulating space in the accelerating tube to change the magnetic flux of the exciting coil to accelerate the beam. The induction accelerator according to claim 1, wherein a capacitor is provided in an insulating space directly connected to the exciting coil. 2. The induction type accelerator according to claim 1, wherein the dielectric of the capacitor is water. 3. The induction type accelerator according to claim 1, wherein the dielectric of the capacitor is ceramic.