Method for evaluating breakdown delay and jitter performance of gas switch

Abstract

The invention discloses a method for evaluating breakdown delay and jitter performance of a gas switch, and relates to the technical field of gas switches. According to the method disclosed by the invention, through searching data of the melting point, the density, the specific heat capacity and the work function of the electrode material and calculating the change of the work function of the binary alloy material, the breakdown time delay and the jitter performance of different electrode materials can be directly evaluated; compared with a conventional method for comparing the breakdown time delay and jitter performance of gas switches made of different electrode materials through a large number of experiments, a large amount of working time and workload can be reduced, so that the experiment efficiency can be improved, and the experiment cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of gas switches, and more particularly to a method for evaluating breakdown delay and jitter performance of a gas switch. Background Art

[0002] Gas spark switches are key components for realizing electric power amplification in pulse devices. They have the advantages of simple structure, reliable performance, and easy installation, and are widely used in primary pulse sources. Fast pulse linear transformer driver (FLTD) usually controls the operation of hundreds of thousands of gas switches. How to achieve accurate and reliable triggering control of numerous gas switches is the main practical engineering problem. The structural characteristics require gas switches to have higher reliability, that is, the switches are required to have lower jitter (standard deviation of breakdown delay). Electrode material is one of the important factors affecting the breakdown delay and jitter of gas spark switches. For the same gas switch, the current method is mainly to compare the effects of different electrode materials on the breakdown delay and jitter performance of the switch through experiments. Jitter is the standard deviation of the breakdown delay, and it takes a lot of time and cost to get the results.

[0003] Therefore, it is a difficult problem to obtain the switch breakdown delay and jitter performance of different electrode materials through theoretical calculation. Summary of the invention

[0004] In view of this, the present invention provides a method for evaluating the breakdown delay and jitter performance of a gas switch based on electrode materials, so as to solve the problems of low efficiency and high experimental cost of the existing breakdown delay and jitter experiments of gas switches.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for evaluating the breakdown delay and jitter performance of a gas switch comprises the following steps:

[0007] Step 1: Determine the physical parameters of the metal electrode material of the gas switch to be evaluated; obtain the work function of the metal electrode material to be evaluated Density ρ, specific heat c, melting point T;

[0008] Step 2: Calculate the average work function of metal atoms that undergo field emission on the surface of the electrode material The calculation formula is as follows:

[0009]

[0010] are the work functions of different atoms in the electrode materials, and A and B are their proportions in the electrode materials;

[0011] Step 3: Calculate the variance of the cubic square of the atomic work function caused by field electron emission of the electrode material The calculation formula is as follows:

[0012]

[0013] Step 4: Use numerical calculation software to calculate the expected inverse of the field enhancement factor on the surface of the electrode material after N discharges. and variance The calculation formula is as follows:

[0014]

[0015] R z is the height of the surface protrusion, r is the radius of the surface protrusion; n is the number of discharges at the protrusion position, Z m is the melting depth, ρ is the density, c is the specific heat capacity, T is the melting point, and q is the total heat input to the electrode surface in a single discharge;

[0016] Step 5: Calculate the breakdown delay characteristic parameter K1 of the gas switch of different electrode materials;

[0017]

[0018] Among them, the larger the gas switch breakdown delay characteristic parameter K1 is, the longer the switch breakdown delay is.

[0019] Step 6: Calculate the jitter index K2 of gas switches with different electrode materials. The calculation formula is as follows:

[0020]

[0021] Among them, the smaller the evaluation index K2 is, the better the jitter performance of the material is.

[0022] Preferably, the metal electrode material to be evaluated is a single metal or a multi-element alloy.

[0023] Preferably, in step 1, the work function of the metal electrode material to be evaluated is obtained by searching for data or performing instrument testing. Density ρ, specific heat c, melting point T.

[0024] Preferably, the surface protrusion radius in step 4 is measured by a surface profilometer.

[0025] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The method of the present invention can directly evaluate the breakdown delay and jitter performance of different electrode materials by searching for data on the melting point, density, specific heat capacity, and work function of electrode materials and calculating the change in work function of binary alloy materials. Compared with the previous method of comparing the breakdown delay and jitter performance of gas switches of different electrode materials through a large number of experiments, it can reduce a lot of working time and workload, thereby improving experimental efficiency and reducing experimental costs;

[0027] 2. When the method of the present invention evaluates the breakdown delay and jitter performance of gas switches of different electrode materials, the evaluation results are consistent with the experimental results in most literatures, and the evaluation results are basically consistent with the experimental results, indicating that the method for evaluating the breakdown delay and jitter performance of the gas spark switch of the present invention is accurate and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 The present invention is a flow chart of the calculation of the method for evaluating the breakdown delay and jitter performance of the gas spark switch.

[0030] Figure 2 This is the schematic diagram of the gas spark switch experimental circuit;

[0031] Figure 3 This is the structural diagram of the gas spark switch. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] Taking W70 / Cu alloy, stainless steel and brass as research objects, the jitter performance of gas switches made of these electrode materials is evaluated by the method of the present invention, and the evaluation results are compared with the experimental results. The specific jitter performance and energy evaluation steps are as follows:

[0035] Step 1: Find the melting point T, density ρ, specific heat capacity c and work function of the above electrode materials in the literature and related material manuals The search results are shown in Table 1 below:

[0036] Table 1

[0037]

[0038] Step 2: Calculate the average work function of metal atoms that undergo field emission on the surface of the electrode material The calculation formula is as follows, are the work functions of different atoms in the electrode materials, and A and B are their proportions in the electrode materials, respectively.

[0039]

[0040] The calculation results are shown in the following table:

[0041] Table 2

[0042]

[0043] Step 3: Calculate the variance of the cubic square of the atomic work function caused by field electron emission of the electrode material The calculation formula is as follows:

[0044]

[0045] The calculation results are shown in the following table:

[0046] Table 3

[0047]

[0048] Step 4: Use numerical calculation software to calculate the expected inverse of the field enhancement factor on the surface of the electrode material after 1000 discharges. and variance The calculation formula is as follows: z is the average height of the effective protrusions on the surface, which is 100 μm, and the number is 100. r is the radius of the surface protrusion tip, which is 0.5 μm. n is the number of discharges at the protrusion position, Z m is the melting depth, in cm; ρ is the density, c is the specific heat, T is the melting point, and q is the heat input to the electrode surface in a single discharge, which is 10 J / cm 2 .

[0049]

[0050]

[0051] The calculation results are shown in the following table:

[0052] Table 4

[0053]

[0054] Step 5: Calculate the breakdown delay characteristic parameter K1 of the gas switch of different electrode materials

[0055]

[0056] Substituting the data into the formula, the breakdown delay evaluation indicators of W70 / Cu, stainless steel, H62 brass, Fe, and Cu are calculated to be: 4.58×10 -2 4.508×10 -2 4.5316×10 -2 That is, using the method of the present invention, the average breakdown delay time of the three electrode materials is ranked from long to short as W70 / Cu, H62 brass, and stainless steel.

[0057] Step 6: Calculate the jitter index K2 of the gas switch with different electrode materials. The calculation formula is as follows;

[0058]

[0059] Substituting the data into the formula, the breakdown jitter parameters of W70 / Cu, stainless steel, and H62 brass are calculated to be: 9.9×10 -3 , 1.2×10 -2 ,7.85×10 -2 That is, the gas switch jitter rankings of the three electrode materials using the method of the present invention are as follows: H62 brass, stainless steel, and W70 / Cu.

[0060] Meanwhile, the present invention uses W70 / Cu alloy, stainless steel and brass to conduct 50 discharge experiments respectively to measure their breakdown delay and calculate their jitter.

[0061] The schematic diagram of the switch experiment circuit is as follows Figure 2 As shown, a two-gap gas switch and two capacitors form a short-circuit discharge loop, the positive and negative high-voltage power supplies charge the two capacitors respectively through a 500kΩ charging resistor, and the fast-front trigger outputs a 15ns negative polarity trigger pulse and applies it to the switch trigger electrode;

[0062] Switch structure such as Figure 3 As shown, the distance between the trigger electrode and the upper and lower electrodes is 5 mm, and the upper and lower electrodes and the trigger electrode are all ring-shaped, with inner and outer diameters of 20 mm and 50 mm respectively;

[0063] The charging voltage is ±25kV, the trigger voltage is -45kV, and the gas pressure is set to 0.15MPa. The switch is aged 500 times before the experiment. Each time the switch breaks down, the switch cavity is ventilated through the gas circuit control system. The starting point of the trigger electrode voltage and the starting point of the loop current are used as the breakdown delay of the switch.

[0064] The experimental results are shown in Table 5 below.

[0065] Table 5

[0066]

[0067] It can be seen from Table 5 that the average breakdown delay time of the three electrode materials is ranked from long to short as W70 / Cu, H62 brass, and stainless steel; the jitter is ranked from large to small as H62 brass, stainless steel, and W70 / Cu. This is completely consistent with the evaluation results of the evaluation method of the present invention, indicating that the method of the present invention is completely accurate and effective.

[0068] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0069] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating breakdown delay and jitter performance of a gas switch, characterized in that: The following steps are involved: Step 1: Determine the physical parameters of the metal electrode material of the gas switch to be evaluated; Obtain the work function of the metal electrode material to be evaluated Density ρ, specific heat c, melting point T; Step 2: Calculate the average work function of metal atoms that undergo field emission on the surface of the electrode material The calculation formula is as follows: are the work functions of different atoms in the electrode materials, and A and B are their proportions in the electrode materials; Step 3: Calculate the variance of the cubic square of the atomic work function caused by field electron emission of the electrode material The calculation formula is as follows: Step 4: Use numerical calculation software to calculate the expected inverse of the field enhancement factor on the surface of the electrode material after N discharges. and variance The calculation formula is as follows: R z is the height of the surface protrusion, r is the radius of the surface protrusion; n is the number of discharges at the protrusion position, Z m is the melting depth, ρ is the density, c is the specific heat capacity, T is the melting point, and q is the total heat input to the electrode surface in a single discharge; Step 5: Calculate the breakdown delay characteristic parameter K1 of the gas switch of different electrode materials; Step 6: Calculate the jitter index K2 of gas switches with different electrode materials. The calculation formula is as follows:

2. A method for evaluating breakdown delay and jitter performance of a gas switch according to claim 1, characterized in that: The metal electrode material to be evaluated is a single metal or a multi-element alloy.

3. A method for evaluating breakdown delay and jitter performance of a gas switch according to claim 2, characterized in that: In step 1, the work function of the metal electrode material to be evaluated is obtained by searching for information or performing instrument testing. Density ρ, specific heat c, melting point T.

4. A method for evaluating breakdown delay and jitter performance of a gas switch according to claim 3, characterized in that: The surface protrusion radius described in step 4 is measured by a surface profilometer.

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