阅读说明：本技术 在强脉冲x射线环境使用的中子计数方法及计数器 (Neutron counting method and counter used in strong pulse X-ray environment ) 是由 王昆仑 张思群 任晓东 于 2020-05-14 设计创作，主要内容包括：本发明公开了一种在强脉冲X射线环境使用的中子计数方法及计数器,该方法包括慢化体、正比计数管、隔离电阻、隔离电容、放大电路、电缆和脉冲电源电路；脉冲电源电路,用于基于脉冲发生器生成的脉冲信号产生脉冲电压,并经电缆和隔离电阻发送给正比计数管；正比计数管,用于基于脉冲电压产生原始计数脉冲信号,并经隔离电容发送给放大电路,原始计数脉冲信号携带有偏压信号；放大电路,用于隔离原始计数脉冲信号携带的偏压信号,获取有效计数脉冲信号,并发送给示波器,以避开正比计数管被脉冲X射线辐照产生电子至电子被气体吸收之前的时间间隔,使得由X射线辐照电离产生的电子不因电场加速而增多,提高中子计数的准确性。(The invention discloses a neutron counting method and a counter used in a strong pulse X-ray environment, wherein the method comprises a moderator, a proportional counter tube, an isolation resistor, an isolation capacitor, an amplifying circuit, a cable and a pulse power supply circuit; the pulse power supply circuit is used for generating pulse voltage based on a pulse signal generated by the pulse generator and sending the pulse voltage to the proportional counter tube through the cable and the isolation resistor; the proportional counting tube is used for generating an original counting pulse signal based on the pulse voltage and sending the original counting pulse signal to the amplifying circuit through the isolating capacitor, and the original counting pulse signal carries a bias signal; the amplifying circuit is used for isolating a bias signal carried by the original counting pulse signal, acquiring an effective counting pulse signal and sending the effective counting pulse signal to the oscilloscope so as to avoid a time interval from the moment that the proportional counting tube is irradiated by the pulse X-ray to generate electrons to the moment that the electrons are absorbed by gas, so that the electrons generated by X-ray irradiation ionization are not increased due to the acceleration of an electric field, and the accuracy of neutron counting is improved.)

1. A method of neutron counting for use in a high-pulse X-ray environment, comprising: the device comprises a moderator, a proportional counter tube, an isolation resistor, an isolation capacitor, an amplifying circuit, a cable and a pulse power supply circuit;

the pulse power supply circuit is used for generating pulse voltage based on a pulse signal generated by the pulse generator and sending the pulse voltage to the proportional counter tube through the cable and the isolation resistor;

the proportional counter tube is used for generating an original counting pulse signal when the pulse voltage reaches a working voltage and reacts with neutrons, and sending the original counting pulse signal to the amplifying circuit through the isolation capacitor, wherein the original counting pulse signal carries a bias voltage signal;

the amplifying circuit is used for isolating the bias signal carried by the original counting pulse signal, acquiring an effective counting pulse signal and amplifying the effective counting pulse signal; and sending the amplified effective counting pulse signal to an oscilloscope.

2. The neutron counting method used in a strong pulse X-ray environment according to claim 1, wherein the pulse power circuit comprises a pulse power supply terminal, a pulse power trigger terminal, a trigger circuit, a switch, a first resistor, a first capacitor, a second resistor, a third resistor and a pulse generator;

the pulse power supply circuit is used for generating pulse voltage based on the pulse signal generated by the pulse generator, and comprises:

the pulse power supply end is used for connecting a power supply to obtain power supply voltage;

when a power supply is connected, the power supply voltage is sent to the first capacitor through the first resistor to supply power to the first capacitor;

when the voltage of the first capacitor is not higher than the working voltage of the proportional counter tube, the pulse generator does not generate a pulse signal, and the terminal voltage of the cable is discharged to the ground through the third resistor;

when the voltage of the first capacitor is higher than the working voltage of the proportional counter tube, the pulse generator sends a pulse signal through the pulse trigger end;

when the pulse generator generates a pulse signal and outputs the pulse signal through the pulse power supply trigger end, the switch is opened, the first capacitor sends the corresponding voltage to the second resistor through the switch, and then the pulse voltage is output through the second resistor.

3. The method of claim 1, wherein the raw counting pulse signal further carries a positive pulse bias signal caused by the rising of the pulse voltage and a negative pulse bias signal caused by the falling of the pulse voltage.

4. The method of claim 3, wherein the amplifying circuit comprises an amplifier, a second capacitor, a fourth resistor, and a diode;

the amplifying circuit is configured to isolate the bias signal carried by the original counting pulse signal, obtain an effective counting pulse signal, and amplify the effective counting pulse signal, and includes:

the diode in the amplifying circuit is used for shunting a positive pulse bias signal carried in the original counting pulse signal;

the second capacitor and the second resistor are used for isolating a negative pulse bias signal carried by the original counting pulse signal to obtain an effective counting pulse signal;

the amplifier is used for amplifying the effective counting pulse signal.

5. The method of claim 1, wherein the isolation resistor is a resistor having a resistance value of 10k-100k ohms.

6. The method of claim 1, wherein the isolation capacitor has a capacitance value selected from a range of 1 to 5 times a capacitance value of a capacitor distributed between a cathode of the proportional counter tube and an anode of the proportional counter tube.

7. The method of claim 6, wherein the capacitance distributed between the cathode of the proportional counter tube and the anode of the proportional counter tube is between 2 pF and 100 pF.

8. A neutron counter based on the neutron counting method used in the strong pulse X-ray environment of any one of claims 1 to 7, wherein the neutron counter comprises:

the proportional counter tube is arranged in the moderator, the cathode of the proportional counter tube is connected with the moderator, and the anode of the proportional counter tube is respectively connected with the isolation resistor and the isolation capacitor; the isolation resistor is connected with the pulse power supply circuit through the cable, and the isolation capacitor is connected with the amplifying circuit.

9. The neutron counter used in a strong pulse X-ray environment according to claim 8, wherein a power supply end of the pulse power supply is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the first capacitor and the first end of the switch, respectively, the other end of the first capacitor is grounded, the second end of the switch is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor and one end of the cable, respectively, the other end of the third resistor is grounded, and the third end of the switch is connected to the pulse generator.

10. The neutron counter of claim 8, wherein the isolation capacitor is connected to the anode of the diode, one end of the fourth resistor, and one end of the second capacitor, respectively, the other end of the second capacitor is connected to the input terminal of the amplifier, and the other input terminal of the amplifier, the cathode of the diode, and the other end of the fourth resistor are grounded; and the output end of the amplifier is connected with an oscilloscope.

Technical Field

The invention relates to the field of pulse neutron measurement, in particular to a neutron counting method and a counter used in a strong pulse X-ray environment.

Background

The neutron counter is also called as a long neutron counter, the traditional long neutron counter adopts a hydrogen-containing material to moderate neutrons, and then utilizes a proportional counting tube with constant voltage and an amplifier connected with the proportional counting tube to generate an electric pulse signal corresponding to neutron counting, so as to complete the counting of the neutrons. Because the proportional counting tube in the neutron counter is actually a high-gain electronic amplifier, when the proportional counting tube is irradiated by strong pulse X-rays, secondary electrons generated by bombarding gas molecules rapidly move towards the anode and are absorbed under the action of an electric field in the proportional counting tube in the process that electrons generated by X-ray irradiation ionization move towards the anode, so that a large amount of positive ions are remained in the proportional counting tube, and the positive ions move towards the cathode. When more positive ions exist in the proportional counting tube, the time of moving towards the cathode is longer, so that an electric field in the proportional counting tube cannot be recovered in time, an electric pulse signal corresponding to neutron counting is reduced or even disappears, and the neutron counting is inaccurate.

Disclosure of Invention

The invention aims to solve the technical problem that the conventional neutron counter has inaccurate neutron counting under the irradiation of strong pulse X-rays. Therefore, the neutron counting method and the counter used in the strong pulse X-ray environment are provided, and the accuracy of neutron counting is improved.

The invention is realized by the following technical scheme:

a method of neutron counting for use in a high-pulse X-ray environment, comprising: the device comprises a moderator, a proportional counter tube, an isolation resistor, an isolation capacitor, an amplifying circuit, a cable and a pulse power supply circuit;

the pulse power supply circuit is used for generating pulse voltage based on a pulse signal generated by the pulse generator and sending the pulse voltage to the proportional counter tube through the cable and the isolation resistor;

the proportional counter tube is used for generating an original counting pulse signal when the pulse voltage reaches a working voltage and reacts with neutrons, and sending the original counting pulse signal to the amplifying circuit through the isolation capacitor, wherein the original counting pulse signal carries a bias voltage signal;

the amplifying circuit is used for isolating the bias signal carried by the original counting pulse signal, acquiring an effective counting pulse signal and amplifying the effective counting pulse signal; and sending the amplified effective counting pulse signal to an oscilloscope.

Furthermore, the pulse power supply circuit comprises a pulse power supply end, a pulse power supply trigger end, a trigger circuit, a switch, a first resistor, a first capacitor, a second resistor, a third resistor and a pulse generator;

the pulse power supply circuit is used for generating pulse voltage based on the pulse signal generated by the pulse generator, and comprises:

the pulse power supply end is used for connecting a power supply to obtain power supply voltage;

when a power supply is connected, the power supply voltage is sent to the first capacitor through the first resistor to supply power to the first capacitor;

when the voltage of the first capacitor is not higher than the working voltage of the proportional counter tube, the pulse generator does not generate a pulse signal, and the terminal voltage of the cable is discharged to the ground through the third resistor;

when the voltage of the first capacitor is higher than the working voltage of the proportional counter tube, the pulse generator sends a pulse signal through the pulse trigger end;

when the pulse generator generates a pulse signal and outputs the pulse signal through the pulse power supply trigger end, the switch is opened, the first capacitor sends the corresponding voltage to the second resistor through the switch, and then the pulse voltage is output through the second resistor.

Further, the original counting pulse signal also carries a positive pulse bias signal caused by the rising of the pulse voltage and a negative pulse bias signal caused by the falling of the pulse voltage.

Further, the amplifying circuit comprises an amplifier, a second capacitor, a fourth resistor and a diode;

the amplifying circuit is configured to isolate the bias signal carried by the original counting pulse signal, obtain an effective counting pulse signal, and amplify the effective counting pulse signal, and includes:

the diode in the amplifying circuit is used for shunting a positive pulse bias signal carried in the original counting pulse signal;

the second capacitor and the second resistor are used for isolating a negative pulse bias signal carried by the original counting pulse signal to obtain an effective counting pulse signal;

the amplifier is used for amplifying the effective counting pulse signal.

Further, the isolation resistor is a resistor with a resistance value of 10k-100k ohms.

Furthermore, the capacitance value of the isolation capacitor is 1-5 times of the capacitance distributed between the cathode of the proportional counting tube and the anode of the proportional counting tube.

Further, the size of the capacitance distributed between the cathode of the proportional counter tube and the anode of the proportional counter tube is 2-100 pF.

A neutron counter based on the neutron counting method used in a strong pulse X-ray environment, the neutron counter comprising:

the proportional counter tube is arranged in the moderator, the cathode of the proportional counter tube is connected with the moderator, and the anode of the proportional counter tube is respectively connected with the isolation resistor and the isolation capacitor; the isolation resistor is connected with the pulse power supply circuit through the cable, and the isolation capacitor is connected with the amplifying circuit.

Further, the pulse power supply end is connected with one end of a first resistor, the other end of the first resistor is connected with one end of a first capacitor and the first end of a switch respectively, the other end of the first capacitor is grounded, the second end of the switch is connected with one end of a second resistor, the other end of the second resistor is connected with one end of a third resistor and one end of a cable respectively, the other end of the third resistor is grounded, and the third end of the switch is connected with the pulse generator.

Furthermore, the isolation capacitor is respectively connected with the anode of the diode, one end of the fourth resistor and one end of the second capacitor, the other end of the second capacitor is connected with the input end of the amplifier, and the other input end of the amplifier, the cathode of the diode and the other end of the fourth resistor are grounded; and the output end of the amplifier is connected with an oscilloscope.

The invention provides a neutron counting method and a counter used in a strong pulse X-ray environment, which adopts a pulse power supply circuit to generate pulse voltage to supply power to a proportional counting tube so as to avoid the time interval from the time when the proportional counting tube is irradiated by pulse X-rays to generate electrons until the electrons are absorbed by gas, so that the electrons generated by X-ray irradiation ionization are not increased due to the acceleration of an electric field, the proportional counting tube can generate an original counting pulse signal corresponding to neutron counting when the pulse voltage arrives, and the original counting pulse signal is processed through an isolation resistor, an isolation capacitor and an amplifying circuit so as to obtain an effective counting pulse signal and improve the accuracy of neutron counting.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a flow chart of a neutron counting method of the present invention for use in a high-pulse X-ray environment.

Fig. 2 is a specific flowchart of step S10 in fig. 1.

Fig. 3 is a specific flowchart of step S30 in fig. 1.

FIG. 4 is a schematic circuit diagram of a neutron counter used in a high-pulse X-ray environment in accordance with the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.