JPH0251231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a sealed discharge switch used in a capacitor discharge and crowbar circuit in an impulse current generator using capacitor discharge.

Recently, pulsed large currents are required for nuclear fusion, pulsed ultra-strong lasers, pulsed ultra-strong magnetic field generation, etc., and many impulse large current generators using capacitor discharge are being used.

One of the performance requirements for the discharge switch used in these devices is the need for low jitter time.

Figure 1 shows the principle of a conventional discharge switch, where a is the circuit diagram used, b is a sectional view of the discharge switch, and Y-
It has a circular cross section symmetrical to the Y' axis, and only the trigger terminal 4 protrudes in one direction.

Identical and corresponding parts in FIGS. 1a and b above are given the same numbers.

The operating principle of this switch is that the main discharge electrodes 1 and 2
A capacitor charging voltage is applied between them, and a voltage obtained by dividing the voltage between the main discharge electrodes 1 and 2 is applied to the trigger electrode 3. When a trigger pulse generated by the starting pulse generator 20 is applied to the trigger electrode 3 through the coaxial cable 22 and the capacitor 15, a discharge first occurs between the trigger electrode 3 and the main discharge electrode 2, and then the trigger electrode 3 A discharge occurs between the main discharge electrode 1 and the main discharge electrode 1, and ultimately the discharge occurs between the main discharge electrode 1 and the main discharge electrode 2, and the charge accumulated in the main capacitor 14 is discharged to the load 19. Reference numeral 6 denotes an insulator constituting a part of the hermetic container, 7 an external connection terminal provided with the main discharge electrode 1 and constituting the lid plate of the hermetic container, and 8 provided with the main discharge electrode 2 and the lid plate of the hermetic container. 13 is a capacitor discharge switch, 16 is a charging resistor for charging the main capacitor 14, 17 is a voltage dividing resistor, 18 is an impulse current generator,
21 is a trigger charging terminal.

Before the first discharge in this process, that is, the first discharge between the trigger electrode 3 and the main discharge electrode 2, occurs, the inside of the capacitor discharge switch 13 is a closed space, and there are almost no ions, etc. that become seeds of discharge. However, the disadvantage was that discharge was difficult to occur, and there was a time delay of several tens of nanoseconds and jitter between the time a trigger voltage was applied and the discharge occurred.

The present invention aims to eliminate the above-mentioned drawbacks, improve the structure of the trigger electrode, and provide a discharge switch with low jitter time.

The present invention will be explained below with reference to the circuit diagram shown in FIG.

In FIG. 2, the same parts as in FIG. 1 are given the same numbers.

13 is a capacitor discharge switch, in which the trigger electrode 3 is structurally supported only by an insulator 5 between it and the trigger terminal 4;
A minute gap 12 is provided between the trigger terminal 4 and the trigger terminal 4. The insulation resistance between the trigger electrode 3 and the trigger terminal 4 is about 10 ⁷ to 10 ¹⁰ Ω due to the insulator 5, and the insulation resistance around the trigger electrode 3 is orders of magnitude higher than this because the other area around the trigger electrode 3 is gas-insulated. Further, the stray capacitance between the trigger electrode 3 and the trigger terminal 4 is made smaller by reducing the supporting area, and the stray capacitance between the trigger electrode 3 and the main discharge electrodes 1 and 2 is made larger than the above-mentioned stray capacitance.

The operating principle of the switch of the present invention is that the trigger terminal 4
When a trigger electrode that rises quickly is applied, a spark discharge occurs in the minute gap 12 between the trigger electrode 3 and the trigger terminal 4, and the space inside the capacitor discharge switch 13 is irradiated with ultraviolet rays generated at this time, generating ions. Trigger electrode 3 and main discharge electrode 1
There is no delay in discharge between the two, and jitter time can be reduced.

The jitter time measured by the discharge switch of the present invention was less than 5 nanoseconds.

FIG. 3 is a circuit diagram of another embodiment in which the discharge switch of the present invention is used in a capacitor discharge circuit.
As in the case of FIG. 2, the jitter time of the discharge switch can be reduced.

FIG. 4 is a cross-sectional view of one embodiment of the discharge switch of the present invention, and FIG. 5 is a cross-sectional view of another embodiment of the discharge switch of the present invention.

In FIGS. 4 and 5, the same parts as in FIGS. 1 to 3 are given the same numbers.

1 and 2 are main discharge electrodes, 3 is a trigger electrode,
4 is a trigger terminal; 5 is an insulator; 6 is an insulator forming a part of the airtight container; 7 is an external connection terminal provided with the main discharge electrode 1 and forming a cover plate of the airtight container; 8
1 is an external connection terminal provided with the main discharge electrode 2; 9 is an insulator that supports and fixes the trigger terminal 4; and 10 is a gas inlet/exhaust hole for inserting and discharging gas; 11 is an insulator A sealed container composed of a material 6, external connection terminals 7 and 8, and an insulator 9,
This closed container 11 is filled with gas. 12 is a minute gap provided between the trigger electrode 3 and the trigger terminal 4.

In the discharge switch of the present invention, three electrodes, main discharge electrodes 1 and 2, trigger electrode 3, and one terminal, trigger terminal 4, are housed in the same sealed container 11, and the trigger electrode 3 and trigger terminal 4 are housed in the same sealed container 11. A small space in between
12.

As described above, the present invention and the discharge switch have a small gap between the trigger electrode and the trigger terminal, thereby reducing the jitter time, and are of great industrial and practical value.

[Brief explanation of drawings]

Figure 1a is a circuit diagram of an example of a conventional discharge switch used in a capacitor discharge circuit, b is a sectional view of the conventional discharge switch, and Figure 2 is a circuit diagram of a conventional discharge switch used in a capacitor discharge circuit. FIG. 3 is a circuit diagram of another embodiment in which the discharge switch of the present invention is used in a capacitor discharge circuit, and FIG. 4 is a cross section of an embodiment of the discharge switch of the present invention. 5 are sectional views of other embodiments of the discharge switch of the present invention. 1, 2: Main discharge electrode, 3: Trigger electrode, 4:
Trigger terminal, 11: Closed container, 12: Micro gap.

Claims (1)

[Claims] 1. A sealed air discharge switch used in an impulse current generating device by capacitor discharge, which is equipped with a pair of first and second main discharge electrodes and a third trigger electrode located between them. The trigger electrode is supported only by a trigger terminal that provides a trigger pulse through an insulator, and the third
A minute gap is provided between the trigger electrode and the trigger terminal to electrostatically make the potential of the third trigger electrode equal to the potential of the trigger terminal, and further between the first and second main discharge electrodes and the trigger terminal. When the capacitance between the third trigger electrode and the trigger terminal is made smaller than the capacitance between the trigger electrodes of No. 3 and a pulse voltage is applied to the trigger terminal, the discharge occurs between the minute intervals. A discharge switch characterized in that it has a function of applying a pulse voltage to the third trigger electrode and irradiating the space between the first and second main discharge electrodes with ultraviolet light generated by the minute discharge.