JPH04326809A - Pulse generator - Google Patents

Abstract

PURPOSE:To present a high-voltage pulse generator with high insulation reliability which can supply a rectangular wave pulse with a fast rise speed and a wide pulse width. CONSTITUTION:A bloom line 7 is composed of multiple spiral lines 72 and 73 arranged in a conductor cylinder 71 and by using this bloom line 7 and a switching element 5, the pulse generator is constituted. The thickness of a conductor constituting the end parts of the spiral lines 72 and 73 is made thicker than that of a conductor at the central parts of the spiral lines. As the result of thickening the conductor, there is no sharp edge part and an electric field is lowered at the end parts of the spiral lines. Therefore, no insulation destruction is generated even when the high voltage is impressed.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse generator for supplying high-voltage rectangular wave pulses to electron guns, klystrons, and the like.

0003

2. Description of the Related Art Conventionally, a rectangular wave pulse generator that combines a capacitance element, an inductance element, and a thyratron has often been used as a high voltage pulse generator. FIG. 3 is an example of a rectangular wave pulse generator using a thyratron. In this device, a rectangular wave pulse can be generated in a load 5 by charging a pulse generating circuit 2 to a constant voltage using a charging power source 1 and then turning on a thyratron 3.

In this case, the withstand voltage of the thyratron 3 is usually several tens of kV, and if a voltage higher than that is to be generated, a pulse transformer 4 is used to boost the voltage as shown in FIG. When using the pulse forming circuit 2, the impedance of the circuit needs to be equal to the impedance of the load 5, and the output voltage is 1/1 of the charging voltage on the temporary side of the pulse transformer.
It becomes 2.

In order to increase the output voltage to a high voltage, there is a method other than using a pulse transformer, in which pulse forming lines such as Blumlein type and stack line type are connected in series. FIG. 4 shows a rectangular wave pulse generator using Blumlein 6, and this device uses thyratron 3 as a switching element. When such a Blumlein is used, the surge impedance between the first conductor 61 and the second conductor 62 is Z1, and the surge impedance between the second conductor 62 and the third conductor 63 is Z2.
and when the impedance of load 5 is R, R/2
If =Z1 =Z2, a rectangular wave pulse with a voltage equal to the charging voltage is obtained as the output.

[0006]

[Problem to be solved by the invention] By the way, in order to increase the efficiency of particle acceleration using a high-frequency amplifier tube such as a klystron, it is necessary to increase the voltage of the pulse to speed up the rise and further improve the flatness of the rectangular wave. There is.

However, when the above-mentioned Blumlein type pulse forming line is used in order to increase the pulse generation voltage and shorten the rise time, there are the following problems. .

That is, in the conventional Blumlein type pulse forming line, the pulse width is determined by the round trip propagation time of the line, so in order to obtain a pulse with a wide pulse width of several hundred ns, for example, the line length must be several tens of meters. The Blumlein line will be needed. Furthermore, in order to match the impedance of the Blumlein line with a high impedance load such as a klystron, the width of the hollow portion of the Blumlein line must be made extremely large. For these reasons, supplying a wide pulse voltage to a high impedance load requires a huge Blumlein line, which is extremely difficult to install in practice.

As one device for solving this problem, as shown in FIG. 5, there is a device in which the Blumlein line 7 is composed of a conductor cylinder and a double spiral conductor installed inside the cylinder. That is, in this device, the first conductor 61 of the circuit shown in FIG. Note that the switching element 3 is provided between the intermediate spiral conductor 72 and the center spiral conductor 73. According to this device, the surge impedance of the line increases, and it is possible to match the load with a relatively small line.

However, in this device, the edges of the spiral conductor are exposed at both ends 74, and the edges are angular, so that the electric field tends to be high. Therefore, depending on the magnitude of the electric field in this portion, there is a problem that dielectric breakdown of the insulating medium charged inside the cylindrical conductor is likely to occur.

[0011] In order to lower the electric field at both ends 74,
If a conductor unrelated to the pulse generation circuit is attached, such as a shield electrode, the output waveform will be distorted by the stray capacitance of that conductor. Therefore, it was not possible to attach a shield electrode, and it was difficult to maintain insulation when generating high voltage pulses.

The present invention has been proposed to solve the problems of the prior art as described above. That is, an object of the present invention is to provide a pulse generator with high insulation reliability, which can supply a rectangular wave pulse with a high voltage, a fast rise time, and a wide pulse width.

[Configuration of the invention]

[0014]

[Means for Solving the Problems] As a means for achieving the above object, the present invention includes a Blumlein line connected to a charging power source and a switching element, and a load connected to the Blumlein line. On the other hand, in a pulse generator that generates a rectangular wave pulse, the Blumlein line is constituted by a multiple spiral line arranged in a conductor cylinder, and the thickness of the conductor constituting the end of the spiral line is determined by the thickness of the conductor forming the end of the spiral line. It is characterized by being thicker than the thickness of the conductor in the center of the.

[0015]

[Function] In the pulse generator of the present invention having the above configuration, as a result of making the conductor thicker, the angular edge portion is eliminated, the electric field at the end of the spiral line is lowered, and a high voltage can be applied. Also, no dielectric breakdown occurs.

[0016]

[Embodiment] An embodiment of the present invention will be explained in detail below with reference to FIGS. 1 and 2. Note that the same members as in the prior art shown in FIGS. 3 to 5 are denoted by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, as shown in FIG.
Spiral-shaped central conductor 71 wound on insulator 8
and an intermediate conductor 72 are arranged inside the conductor cylinder 73 to form a double spiral Blumlein line 7. In addition, a spiral center conductor 71 and an intermediate conductor 7
2, as shown in the enlarged view of FIG. 2, the conductor 9 at the input end and the output end of the line is configured to be thicker than the conductor 10 in the middle.

In the pulse generator of this embodiment having such a configuration, the intermediate conductor 72 charged by the charging power source 1 via the resistor 2 is grounded by closing the switching element 5. Then, a step wave having a rise time determined by the characteristics of the switching element 3 is input to the distributed constant line composed of the conductor cylinder 71 and the intermediate conductor 72. A rectangular wave voltage is applied to the load 4 by this step wave reciprocating within the double spiral line.

At this time, at the input end and output end 74 of the spiral conductor, the thickness of the conductor 9 is configured to be larger than the thickness of the conductor 10 in the middle, so there is no sharp edge around the conductor 9, and the conductor 9 has no sharp edges. The electric field in the area can be kept low. Therefore, no dielectric breakdown occurs. Further, in order to lower the electric field at the end portion 74, no electrode unrelated to the circuit that generates pulses, such as a shield electrode, is used, so there is no distortion in the output waveform.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but as a conductor at the end of a spiral line, an insulator is wrapped thickly around a conductor having the same thickness as the middle part of the line, and then You may also use a thin conductor that is thicker than the intermediate conductor by wrapping it around the conductor.

[0021]

[Effects of the Invention] As described above, according to the present invention, by simply making the conductor at the end of the spiral conductor constituting the Blumlein thicker than the conductor in the middle, excellent insulation reliability is achieved and high voltage is achieved. It is possible to provide a pulse generator that can supply a rectangular wave pulse that rises quickly and has a wide pulse width.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a pulse generator of the present invention.

FIG. 2 is an enlarged side view of the conductor end of the embodiment of FIG. 1;

FIG. 3 is a circuit diagram of a conventional pulse generator using a thyratron.

FIG. 4 is a circuit diagram of a pulse generator using Blumlein.

FIG. 5 is a perspective view showing the conventional configuration of the pulse generator shown in FIG. 4;

[Explanation of symbols]

1...Charging power source 3...Switching element 4...Pulse transformer 5...Load 6,7...Blumlein 71...Conductor cylinder 72...Middle spiral conductor 73...Center spiral conductor 8...Insulator 9... End conductor 10... Conductor in the middle

Claims (1)

[Claims] 1. A pulse generator comprising a Blumlein line connected to a charging power supply and a switching element, and generating a rectangular wave pulse to a load connected to the Blumlein line, wherein the Blumlein line is It is composed of multiple spiral lines placed inside a conductor cylinder, and the thickness of the conductor that makes up the end of this spiral line is
A pulse generator characterized in that the thickness of the conductor is greater than that of the conductor at the center of the spiral line.