A high-voltage pulse direct-current high-current pulsed neutron generator

Abstract

The application provides a direct-current high-voltage pulse strong-current pulse neutron generator, and relates to the technical field of neutron generators, comprising a main arc power module (3), a high-voltage accelerating power module (9) and a neutron tube (12). The neutron generator of the application is a strong-current pulse neutron generator working and driven in a direct-current high-voltage accelerating and pulse mode, can realize adjustable pulse parameters, is simpler to realize, widens the neutron pulse width from sub-microsecond to several milliseconds, and is helpful to widen the application field of the strong-current pulse neutron generator. For example, the ms-level strong-current pulse neutron source can be applied to the mass flow rate and component measurement based on neutron activation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of strong current pulsed neutron generator, and particularly relates to a direct current high voltage pulsed working strong current pulsed neutron generator. BACKGROUND

[0002] The vacuum arc ion source with hydrogen (deuterium) electrode, also known as spark ion source, originated in the 1950s, and is mainly used for generating strong current pulsed hydrogen (deuterium) ion beam. Compared with the traditional ion source, the ion source does not need to additionally introduce neutral gas components during the discharge pulse process. A variety of metal materials in the transition region of the periodic table can absorb a large amount of hydrogen through the exothermic process, and store hydrogen in the solid material, which has a very high hydrogen storage density. The vacuum arc pulsed ion beam with hydrogen (deuterium) electrode is mainly applied to the strong current pulsed neutron generator, which is a special neutron source capable of generating strong pulsed neutrons in a short pulse width time. From the principle and structure, it is a miniature low-energy particle accelerator, mainly composed of a vacuum arc ion source, a beam optical system, a target and other auxiliary components. The structure is usually compact, and each component is packaged in a ceramic tube or a glass tube to form a special electric vacuum device (usually referred to as a neutron tube), which, combined with an external power supply system, constitutes a strong current pulsed neutron generator. Under the action of a large current, the deuterium electrode releases deuterium gas and metal vapor, and at the same time, ionizes to generate high-density plasma containing deuterium ions and other metal ions. The plasma is expanded through the expansion cup, and then accelerated by the high voltage in the beam optical zone. The deuterium target or tritium target is bombarded to generate neutrons through the thermonuclear reaction. The neutron tube based on the Penning and radio frequency ion source generally works in a continuous mode, and the ion current is usually in the order of 100 muA. The strong current pulsed neutron generator has significant differences. The working current of the neutron generator is usually in the order of 100 mA to A, the working pulse width is from sub-microsecond to several milliseconds, and the neutron generator has the characteristics of strong current, high pulse neutron yield and compact size. It has been widely used in important fields such as oil logging, chemical warfare agent detection, illegal goods detection, uranium ore detection, biomedical, deep earth and extraterrestrial exploration.

[0003] The strong current pulsed neutron generator usually adopts pulsed high voltage to accelerate ions to hit the target to generate pulsed neutrons. The pulsed high voltage is usually generated by a high-voltage pulse transformer, and the primary current of the pulse transformer is usually generated by a high-voltage large-current switch with a withstand voltage of several kV. Compared with direct current high voltage, the pulse high voltage has a short action time, and the insulation material can withstand a higher pulse voltage amplitude. The driving mode of the neutron generator using pulsed acceleration high voltage is easy to realize a smaller size. The strong current pulsed neutron generator produced by the Russian All-Russian Automation Institute currently adopts the pulsed high voltage acceleration mode, and has small size and high acceleration voltage.

[0004] But the pulse acceleration mode is limited by high-voltage pulse transformer and high-voltage switch device with high repetition frequency, so that the neutron generator pulse width is short, and the output neutron pulse width is not adjustable. At the same time, the pulse transformer parameter design requires extremely high, and is affected by the overall assembly structure distribution parameter of the generator, so that the pulse transformer parameter design and control are more difficult; and the long-life high-voltage switch device with high repetition frequency is also a key technical difficulty that needs to be overcome in this technical solution. For example, a kind of pulse power system and neutron generator are disclosed in Chinese patent application No. CN 202110388701.7, the high-voltage accelerating power supply adopts a pulse voltage driving mode, four pulse transformers are adopted to realize positive and negative pulse acceleration high voltage, and the ion source main arc driving current is suspended in the high-voltage acceleration voltage.

[0005] Therefore, a strong current pulse neutron generator working and driving mode with direct current high voltage acceleration and pulse mode is proposed in this paper. The pulse parameter can be adjusted, and it is more simple to realize, which can widen the neutron pulse width from sub-microsecond to several milliseconds, and help to widen the application field of strong current pulse neutron generator, such as ms-level strong current pulse neutron source can be applied in mass flow rate and composition measurement based on neutron activation. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, and provide a direct current high voltage pulse working strong current pulse neutron generator. In view of the problems of the prior art, such as difficult pulse transformer design, difficult long-life high-voltage switch implementation, and difficult pulse width adjustment, the following technical solutions are used to realize the purpose:

[0007] A direct current high voltage pulse working strong current pulse neutron generator, comprising a main arc power supply module, a high voltage accelerating power supply module and a neutron tube, wherein: the main arc power supply module is provided with a direct current power supply and a main arc power supply ion source, an energy storage capacitor and a main switch; the main arc power supply ion source, the energy storage capacitor are connected in parallel to the direct current power supply, and the main switch is arranged in the branch of the main arc power supply ion source. By controlling the conduction time of the main switch, the main arc power supply ion source generates a current pulse waveform;

[0008] The high voltage accelerating power supply module is provided with a voltage doubler circuit structure to amplify and output the input voltage;

[0009] The neutron tube comprises a neutron tube ion source, a beam optical system and a target; the neutron tube ion source generates plasma by discharge, and the accelerated ion beam is generated by the beam optical system, and the accelerated ion beam is bombarded onto the target to generate neutrons;

[0010] The main arc power module provides pulse current for the neutron tube, discharges the neutron tube ion source in the neutron tube, and generates plasma; the high-voltage accelerating power module provides direct current voltage for the beam optical system, and the plasma beam is accelerated to hit the target to generate fusion reaction and generate neutrons.

[0011] Optionally or preferably, a current limiting resistor R2 is further arranged in the main arc power module; the current limiting resistor R2 is connected in series with the main arc power ion source, and is used to adjust the current amplitude flowing through the main arc power ion source.

[0012] Optionally or preferably, the high-voltage accelerating power module adopts a voltage doubling circuit structure, and specifically:

[0013] The initial input voltage U in is converted into positive and negative symmetrical alternating voltage U1 and -U1, and the positive and negative symmetrical circuit is recharged to the initial value of the accelerating voltage by the multi-stage capacitor between the pulse gaps to supplement the energy of the circuit; the total energy storage capacitor capacity C0 of the high-voltage accelerating power module satisfies:

[0014] C0·ΔU=I·Δt

[0015] Wherein, ΔU is the voltage drop in the working period of the high-voltage accelerating power module with load; I is the current flow intensity of the high-voltage power supply with load; and Δt is the time period of the high-voltage power supply with load.

[0016] Optionally or preferably, the main arc power module, the high-voltage accelerating power module and the neutron tube are all arranged in the generator shell; the generator shell is provided with a power feeding connector; and the main arc power module and the high-voltage accelerating power module are both electrically connected with an external controller through the power feeding connector.

[0017] Optionally or preferably, the generator shell is filled with an insulating medium; and the insulating medium is one of transformer oil, solid filling or insulating gas.

[0018] Optionally or preferably, the adjustable current amplitude range of the pulse current provided by the main arc power module is 1-1000A, and the adjustable pulse width range of the pulse current is 100ns-10ms.

[0019] Optionally or preferably, the trigger voltage output by the main arc power module is 1-10kV.

[0020] Optionally or preferably, the voltage range output by the high-voltage accelerating power module is 10-200kV, and the pulse output current range is 10mA-10A, and generally a larger pulse current intensity is output when the working pulse width is smaller

[0021] Based on the above technical solutions, the following technical effects can be achieved:

[0022] The direct-current high-voltage pulse working high-current pulse neutron generator can realize adjustable pulse parameters, is simpler to realize, widens neutron pulse width from sub-microsecond to several milliseconds, and is helpful to widen application fields of the high-current pulse neutron generator. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without any creative effort.

[0024] Figure 1 The direct-current high-voltage pulse working high-current pulse neutron generator in the present application;

[0025] Figure 2 The circuit structure diagram of the intermediate power module in the present application;

[0026] Figure 3 The circuit structure diagram of the double-voltage high-voltage acceleration module in the present application;

[0027] Figure 4 The circuit principle diagram of the direct-current high-voltage pulse working high-current pulse neutron generator in the present application;

[0028] Figure 5 The working principle simulation calculation of the direct-current high-voltage pulse working high-current pulse neutron generator in the present application;

[0029] In the figure: 1 - feeder connector, 2 - main arc power module control connection line, 3 - main arc power module, 4 - main arc power module output connection line, 5 - generator shell, 6, controller and neutron generator connection line, 7 - controller, 8 - high-voltage acceleration power module control line, 9 - high-voltage acceleration power module, 10, high-voltage acceleration power module output connection line, 11 - insulating medium, 12 - neutron tube,

[0030] 301 - DC power supply, 302 - main arc power ion source, 303 - energy storage capacitor, 304 - main switch. DETAILED DESCRIPTION

[0031] It should be understood that the specific embodiments described herein are merely intended to explain the present application and are not intended to limit the present application.

[0032] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0033] Embodiment 1

[0034] As shown in the formula (1) : Figures 1-5

[0035] The embodiment provides a direct-current high-voltage pulse working high-current pulsed neutron generator, which comprises a main arc power supply module 3, a high-voltage accelerating power supply module 9 and a neutron tube 12, wherein:

[0036] The main arc power supply module 3 is internally provided with a direct-current power supply 301 and a main arc power supply ion source 302, an energy storage capacitor 303 and a main switch 304; the main arc power supply ion source 302 and the energy storage capacitor 303 are connected in parallel to the direct-current power supply 301, and the main switch 304 is arranged on a branch in which the main arc power supply ion source 302 is located; by controlling the conduction time of the main switch 304, the main arc power supply ion source 302 generates a current pulse waveform; in the embodiment, the conduction resistance of the main arc power supply ion source 302 after breakdown is less than 1Ω; and the current amplitude flowing through the main arc power supply ion source 302 is determined by a current-limiting resistor R2.

[0037] The high-voltage accelerating power supply module 9 is internally provided with a voltage doubler circuit structure to amplify and output an input voltage.

[0038] The neutron tube 12 internally comprises a neutron tube ion source, a beam optical system and a target; the neutron tube ion source can be ionized into plasma, and the accelerated ion beam is accelerated by the beam optical system and bombarded onto the target to generate neutrons.

[0039] The main arc power supply module 3 provides a pulse current for the neutron tube 12, discharges the neutron tube ion source in the neutron tube 12 to generate plasma; and the high-voltage accelerating power supply module 9 provides a direct-current voltage for the beam optical system, so that the ion beam is accelerated and bombarded onto the target to generate neutrons through a thermonuclear reaction.

[0040] In the embodiment, the main arc power supply module 3 is further provided with a current-limiting resistor R2; the current-limiting resistor R2 is connected in series with the main arc power supply ion source 302, and is used to adjust the current amplitude flowing through the main arc power supply ion source 302.

[0041] In the embodiment, the high-voltage accelerating power supply module 9 adopts a voltage doubler circuit structure, and a double voltage doubler circuit structure is described as an example:

[0042] The initial input voltage U in ​The alternating voltage U1 and -U1 are transformed into positive and negative symmetrical alternating voltage, and the circuit is recharged to the initial value of the accelerating voltage by the energy supplement between the pulse gaps by the multi-stage capacitor. Figure 3 As shown in the figure, the high voltage end of the alternating voltage is grounded, and the number of voltage doubling stages is N. In an ideal case, the output voltage can reach 2N times of the alternating voltage U1. The total energy storage capacitor capacity CO of the high-voltage accelerating power supply module 9 satisfies:

[0043] C0·ΔU=I·Δt

[0044] Where ΔU is the voltage drop in the working period of the high-voltage accelerating power supply module 9 under load; i is the current flow strength of the high-voltage power supply under load; and Δt is the time period of the high-voltage power supply under load.

[0045] In this embodiment, the voltage drop ΔU is about 10% of the initial input voltage U in ; I is also the beam current flow strength of the neutron tube 12, which is in the order of hundreds of mA to A.

[0046] In this embodiment, the main arc power supply module 3, the high-voltage accelerating power supply module 9, and the neutron tube 12 are all installed in the generator housing 5; the generator housing 5 is provided with a power feeding connector 1; and the main arc power supply module 3 and the high-voltage accelerating power supply module 9 are both electrically connected to the external controller 7 through the power feeding connector 1.

[0047] In this embodiment, the generator housing 5 is filled with an insulating medium 11; the insulating medium 11 is one of transformer oil, solid filling, or insulating gas, and the miniaturization of the neutron generator can be achieved by filling the insulating medium.

[0048] In this embodiment, in the fields of oil logging and uranium exploration, the neutron pulse width parameter commonly used is 1-20 μs. In order to meet the detection requirements, in this embodiment, the adjustable current amplitude range of the pulse current provided by the main arc power supply module 3 is 1-1000 A, and the adjustable pulse width range of the pulse current is 100 ns-10 ms.

[0049] In this embodiment, the trigger voltage output by the main arc power supply module 3 is 1-10 kV, and in this embodiment, the trigger voltage is 5 kV.

[0050] The design structure, function and connection form disclosed in the present application can be realized by other ways. For example, the above described embodiments are only illustrative, for example, the working mode of the neutron tube can also select to suspend the ion source above the accelerated high voltage, at this time, the ion source main arc power supply needs to be powered by the isolated power supply; for example, the voltage doubling circuit can also use a single voltage doubling circuit topology according to the practical situation; the energy storage capacitor in the main arc power supply module can also use other current pulse generation methods, such as using a pulse forming line, an inductance energy storage method to generate a current pulse; in addition, each functional component in each embodiment of the present application can be integrated into one functional component, or each functional component can exist physically alone, or two or more functional components can be integrated into one functional component.

[0051] The above described is only the preferred embodiment of the present application, it should be understood that the present application is not limited to the form disclosed herein, should not be considered as excluding other embodiments, and can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein by the above teaching or related art or knowledge. The modification and change made by the person skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.

Claims

1. A direct current high voltage pulsed operating high current pulsed neutron generator, characterized in that: The neutron tube (12) comprises a neutron tube ion source, a beam optical system and a target. The main arc power module (3) is provided with a DC power supply (301), a main arc power ion source (302), an energy storage capacitor (303) and a main switch (304). The main arc power module (3) provides a pulse current for the neutron tube (12), and the neutron tube ion source in the neutron tube (12) is discharged to generate plasma. The main arc power module (3) is provided with a current limiting resistor R2.

2. A high voltage pulsed DC operated high current pulsed neutron generator according to claim 1, characterized in that: The high-voltage accelerating power module (9) adopts a voltage doubling circuit structure, specifically:

3. The high-voltage pulsed operating high-current pulsed neutron generator of claim 1, wherein: C0·ΔU=I·Δt The initial input voltage U is converted through a transformer. in The voltages are converted into symmetrical positive and negative AC voltages U1 and -U1. Multi-stage capacitors replenish the circuit's energy between pulse gaps, recharging the symmetrical circuit back to its initial accelerating voltage value. The total energy storage capacity C0 of this high-voltage accelerating power supply module (9) satisfies: The main arc power module (3), the high-voltage accelerating power module (9) and the neutron tube (12) are all installed in the generator shell (5). The generator shell (5) is filled with an insulating medium (11).

4. The high power pulsed neutron generator of claim 1, wherein: The adjustable current amplitude range of the pulse current provided by the main arc power module (3) is 1-1000A, and the adjustable pulse width range of the pulse current is 100ns-10ms.

5. A high voltage pulsed D-C operated strong current pulsed neutron generator according to claim 4, characterized in that: The trigger voltage output by the main arc power module (3) is 1-10kV.

6. A high voltage pulsed D-C operated strong current pulsed neutron generator according to claim 1, characterized in that: The voltage range output by the high-voltage accelerating power module (9) is 10-200kV, and the pulse output current range is 10mA-10A, usually outputting larger pulse current intensity at smaller working pulse width.

7. The high power pulsed neutron generator of claim 1, wherein: ​ 8. The high power pulsed neutron generator of claim 1, wherein: ​

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