A GM counter tube signal processing circuit

Abstract

The invention discloses a GM counter signal processing circuit, comprising a GM counter, a microcontroller unit, a control switch circuit and a rectangular wave generating circuit; the GM counter inputs the generated pulse-type exponential decay signal into the control switch circuit; the control switch circuit inputs the received pulse-type exponential decay signal into the rectangular wave generating circuit; the rectangular wave generating circuit is used to convert the pulse-type exponential decay signal into a rectangular wave and then input it into the microcontroller unit; the signal output end of the microcontroller unit is connected to the control end of the control switch circuit, and is used to send an interruption control signal to the control switch circuit when the received rectangular wave value is greater than a set value, so that the control switch circuit is disconnected, the leakage path of the GM counter is cut off, and the GM counter stops discharging. This scheme can process the pulse-type exponential decay signal output by the GM counter, and at the same time avoid the phenomenon of continuous discharge of the GM counter under high dose rate.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear radiation detection, and in particular to a GM counter tube signal processing circuit. Background Art

[0002] While nuclear technology is widely used in agriculture, military, medicine and other fields, people have to be vigilant about whether there are radioactive hazards in their environment. Since the α decay and β decay processes are accompanied by the generation of gamma rays (also called γ rays), the monitoring and alarm of γ rays naturally become an important way to monitor the nuclear radiation environment.

[0003] GM counter tubes, also known as Geiger-Muller counter tubes, are widely used in various types of nuclear radiation measurements such as reactor radiation monitoring and environmental radiation monitoring, and are one of the most common gamma detectors. GM counter tubes have the advantages of high sensitivity, large output charge pulse amplitude, good stability, suitability for harsh environments, ease of use, and low manufacturing cost. At present, a large number of military and civilian nuclear radiation monitors at home and abroad use GM counter tubes as detectors.

[0004] When the GM counter tube is performing nuclear radiation detection, based on the nature of nuclear detection events, the signal output by the GM counter tube is a pulse-type exponential decay signal. At the same time, continuous discharge of the GM counter tube at a high dose rate will greatly shorten its life. Therefore, it is necessary to design a signal processing circuit for the GM counter tube to process the pulse-type exponential decay signal output by the GM counter tube and avoid continuous discharge of the GM counter tube at a high dose rate. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a GM counter tube signal processing circuit that can process the pulse-type exponential decay signal output by the GM counter tube and avoid the continuous discharge phenomenon of the GM counter tube at a high dose rate.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A GM counter tube signal processing circuit comprises a GM counter tube, a micro control unit, a control switch circuit and a rectangular wave generating circuit;

[0008] The signal output end of the GM counter tube is connected to the signal input end of the control switch circuit, so as to input the generated pulse-type exponential decay signal into the control switch circuit;

[0009] The signal output terminal of the control switch circuit is connected to the signal input terminal of the rectangular wave generating circuit, and is used to input the received pulse-shaped exponential decay signal into the rectangular wave generating circuit;

[0010] The signal output end of the rectangular wave generating circuit is connected to the signal input end of the micro control unit, and is used to convert the pulse-type exponential decay signal into a rectangular wave and then input it into the micro control unit;

[0011] The signal output end of the microcontroller unit is connected to the control end of the control switch circuit, and is used to send an interrupt control signal to the control switch circuit when the received rectangular wave value is greater than the set value, so that the control switch circuit is disconnected, cutting off the leakage path of the GM counter tube, and the GM counter tube stops discharging.

[0012] The working principle of the present invention is as follows: when the GM counter tube signal processing circuit of the present invention is in normal use, the pulse-type exponential decay signal output by the GM counter tube is input into the rectangular wave generating circuit after passing through the control switch circuit, the rectangular wave generating circuit processes the received pulse-type exponential decay signal to obtain a rectangular wave, and inputs the obtained rectangular wave into the micro control unit, the micro control unit processes the obtained rectangular wave and determines whether the value of the rectangular wave is greater than the set value, if so, the micro control unit sends an interruption control signal to the control switch circuit, the control switch circuit is disconnected, the leakage path of the GM counter tube is cut off, the GM counter tube stops discharging, and on the basis of avoiding high-voltage shutdown switching, the GM counter tube does not have an electric field suitable for work, and gamma ray irradiation cannot ionize it, thereby avoiding the shortening of life caused by continuous discharge. At the same time, by converting the pulse-type exponential decay signal generated by the GM counter tube into a rectangular wave signal, the micro control unit can also facilitate the processing of the signal by the micro control unit.

[0013] Preferably, the control switch circuit includes an N-channel MOS tube Q1, the gate of the N-channel MOS tube Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS tube Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS tube Q1 is connected to the signal output end of the GM counter tube.

[0014] Preferably, the rectangular wave generating circuit includes a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to the power supply VCC, and the other end of the resistor R5 is grounded.

[0015] Preferably, the source of the N-channel MOS transistor Q1 is also grounded through a resistor R3, and the gate of the N-channel MOS transistor Q1 is also grounded through a resistor R2.

[0016] A working method of the GM counter tube signal processing circuit as described above comprises the following steps:

[0017] Step 1) the pulse exponential decay signal output by the GM counter tube is input into the rectangular wave generating circuit after passing through the control switch circuit;

[0018] Step 2) the rectangular wave generating circuit processes the received pulse-shaped exponential decay signal to obtain a rectangular wave, and inputs the obtained rectangular wave into the micro control unit;

[0019] Step 3) The microcontroller unit processes the obtained rectangular wave and determines whether the value of the rectangular wave is greater than the set value, if so, executes step 4), if not, returns to execute step 1);

[0020] Step 4) The micro control unit sends an interruption control signal to the control switch circuit, and the control switch circuit is disconnected, cutting off the leakage path of the GM counter tube, and the GM counter tube stops discharging.

[0021] Preferably, the control switch circuit comprises an N-channel MOS transistor Q1, the gate of the N-channel MOS transistor Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS transistor Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS transistor Q1 is connected to the signal output end of the GM counter tube;

[0022] In step 4), when the micro control unit determines that the rectangular wave value is greater than the set value, the micro control unit sends a low level signal of interrupting control to the gate of the N-channel MOS transistor Q1, so that the N-channel MOS transistor Q1 is turned off.

[0023] Preferably, the rectangular wave generating circuit comprises a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to a power supply VCC, and the other end of the resistor R5 is grounded;

[0024] In step 2), by adjusting the resistance values ​​of the resistor R5 and the resistor R4, the reference level input to the Schmitt trigger N1 is between the reference levels VH+ and VH-, and the pulse-type exponential decay signal output by the GM counter is filtered by the capacitor C1, superimposed on the reference level, and then input to the input end of the Schmitt trigger N1.

[0025] Compared with the prior art, the GM counter tube signal processing circuit of the present invention has anti-interference and failure protection functions, and can avoid the problem of shortened life of the GM counter tube due to continuous discharge at a high dose rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a circuit block diagram of the GM counter tube signal processing circuit of the present invention;

[0027] Figure 2 It is a circuit diagram of the GM counter tube signal processing circuit of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meaning understood by people with general skills in the field to which the present invention belongs.

[0029] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" cover the features, wholes, steps, operations, elements and / or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] As attached Figure 1 As shown, a GM counter tube signal processing circuit includes a GM counter tube, a micro control unit, a control switch circuit and a rectangular wave generating circuit;

[0031] The signal output end of the GM counter tube is connected to the signal input end of the control switch circuit, so as to input the generated pulse-type exponential decay signal into the control switch circuit;

[0032] The signal output terminal of the control switch circuit is connected to the signal input terminal of the rectangular wave generating circuit, so as to input the received pulse-shaped exponential decay signal into the rectangular wave generating circuit;

[0033] The signal output end of the rectangular wave generating circuit is connected to the signal input end of the micro control unit, and is used to convert the pulse-type exponential decay signal into a rectangular wave and then input it into the micro control unit;

[0034] The signal output end of the microcontroller unit is connected to the control end of the control switch circuit, and is used to send an interrupt control signal to the control switch circuit when the received rectangular wave value is greater than the set value, so that the control switch circuit is disconnected, the leakage path of the GM counter tube is cut off, and the GM counter tube stops discharging.

[0035] The working principle of the present invention is as follows: when the GM counter tube signal processing circuit of the present invention is in normal use, the pulse-type exponential decay signal output by the GM counter tube is input into the rectangular wave generating circuit after passing through the control switch circuit, the rectangular wave generating circuit processes the received pulse-type exponential decay signal to obtain a rectangular wave, and inputs the obtained rectangular wave into the micro control unit, the micro control unit processes the obtained rectangular wave and determines whether the value of the rectangular wave is greater than the set value, if so, the micro control unit sends an interruption control signal to the control switch circuit, the control switch circuit is disconnected, the leakage path of the GM counter tube is cut off, the GM counter tube stops discharging, and on the basis of avoiding high-voltage shutdown switching, the GM counter tube does not have an electric field suitable for work, and gamma ray irradiation cannot ionize it, thereby avoiding the shortening of life caused by continuous discharge. At the same time, by converting the pulse-type exponential decay signal generated by the GM counter tube into a rectangular wave signal, the micro control unit can also facilitate the processing of the signal by the micro control unit.

[0036] As attached Figure 2 As shown, in this embodiment, the control switch circuit includes an N-channel MOS transistor Q1, the gate of the N-channel MOS transistor Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS transistor Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS transistor Q1 is connected to the signal output end of the GM counter tube V1.

[0037] In this embodiment, the rectangular wave generating circuit includes a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to the power supply VCC, and the other end of the resistor R5 is grounded. By adjusting the resistance values ​​of the resistor R5 and the resistor R4, the reference level input to the Schmitt trigger N1 can be between the reference levels VH+ and VH-.

[0038] In this embodiment, the source of the N-channel MOS transistor Q1 is also grounded through the resistor R3, and the gate of the N-channel MOS transistor Q1 is also grounded through the resistor R2.

[0039] A working method of the GM counter tube signal processing circuit as described above comprises the following steps:

[0040] Step 1) The pulse exponential decay signal output by the GM counter tube V1 is input into the rectangular wave generating circuit after passing through the control switch circuit;

[0041] Step 2) the rectangular wave generating circuit processes the received pulse-shaped exponential decay signal to obtain a rectangular wave, and inputs the obtained rectangular wave into the micro control unit;

[0042] Step 3) The microcontroller unit processes the obtained rectangular wave and determines whether the value of the rectangular wave is greater than the set value. If so, execute step 4). If not, return to execute step 1);

[0043] Step 4) The microcontroller unit sends an interrupt control signal to the control switch circuit, the control switch circuit is disconnected, the leakage path of the GM counter tube V1 is cut off, and the GM counter tube V1 stops discharging.

[0044] In this embodiment, the control switch circuit includes an N-channel MOS transistor Q1, the gate of the N-channel MOS transistor Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS transistor Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS transistor Q1 is connected to the signal output end of the GM counter tube V1;

[0045] In step 4), when the microcontroller unit determines that the rectangular wave value is greater than the set value, the microcontroller unit sends a low-level signal of interrupting control to the gate of the N-channel MOS transistor Q1, so that the N-channel MOS transistor Q1 is turned off.

[0046] In this embodiment, the rectangular wave generating circuit includes a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to the power supply VCC, and the other end of the resistor R5 is grounded;

[0047] In step 2), by adjusting the resistance values ​​of resistors R5 and R4, the reference level input to the Schmitt trigger N1 is between the reference levels VH+ and VH-. The pulse-type exponential decay signal output by the GM counter V1 is filtered by the capacitor C1, superimposed on the reference level, and then input to the input end of the Schmitt trigger N1.

[0048] Compared with the prior art, the GM counter tube signal processing circuit of the present invention has anti-interference and failure protection functions, and can avoid the problem of shortened life of the GM counter tube V1 due to continuous discharge at a high dose rate.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A GM counter tube signal processing circuit, characterized in that: It includes a GM counter tube, a micro control unit, a control switch circuit and a rectangular wave generating circuit; The signal output end of the GM counter tube is connected to the signal input end of the control switch circuit, so as to input the generated pulse-type exponential decay signal into the control switch circuit; The signal output terminal of the control switch circuit is connected to the signal input terminal of the rectangular wave generating circuit, and is used to input the received pulse-shaped exponential decay signal into the rectangular wave generating circuit; The signal output end of the rectangular wave generating circuit is connected to the signal input end of the micro control unit, and is used to convert the pulse-type exponential decay signal into a rectangular wave and then input it into the micro control unit; The signal output end of the microcontroller unit is connected to the control end of the control switch circuit, and is used to send an interruption control signal to the control switch circuit when the received rectangular wave value is greater than the set value, so that the control switch circuit is disconnected, the leakage path of the GM counter tube is cut off, and the GM counter tube stops discharging; The control switch circuit includes an N-channel MOS transistor Q1, the gate of the N-channel MOS transistor Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS transistor Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS transistor Q1 is connected to the signal output end of the GM counter tube; The rectangular wave generating circuit includes a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to a power supply VCC, and the other end of the resistor R5 is grounded.

2. The GM counter tube signal processing circuit according to claim 1, characterized in that: The source of the N-channel MOS transistor Q1 is also grounded through a resistor R3, and the gate of the N-channel MOS transistor Q1 is also grounded through a resistor R2.

3. A method for operating the GM counter tube signal processing circuit as claimed in claim 1, characterized in that: The following steps are involved: Step 1) the pulse exponential decay signal output by the GM counter tube is input into the rectangular wave generating circuit after passing through the control switch circuit; Step 2) the rectangular wave generating circuit processes the received pulse-shaped exponential decay signal to obtain a rectangular wave, and inputs the obtained rectangular wave into the micro control unit; Step 3) The microcontroller unit processes the obtained rectangular wave and determines whether the value of the rectangular wave is greater than the set value, if so, executes step 4), if not, returns to execute step 1); Step 4) The micro control unit sends an interruption control signal to the control switch circuit, and the control switch circuit is disconnected, cutting off the leakage path of the GM counter tube, and the GM counter tube stops discharging.

4. The operating method of the GM counter tube signal processing circuit according to claim 3, characterized in that: The control switch circuit includes an N-channel MOS transistor Q1, the gate of the N-channel MOS transistor Q1 is connected to the signal output end of the micro control unit, the source of the N-channel MOS transistor Q1 is connected to the signal input end of the rectangular wave generating circuit, and the drain of the N-channel MOS transistor Q1 is connected to the signal output end of the GM counter tube; In step 4), when the micro control unit determines that the rectangular wave value is greater than the set value, the micro control unit sends a low level signal of interrupting control to the gate of the N-channel MOS transistor Q1, so that the N-channel MOS transistor Q1 is turned off.

5. The operating method of the GM counter tube signal processing circuit according to claim 4, characterized in that: The rectangular wave generating circuit comprises a capacitor C1 and a Schmitt trigger N1, one end of the capacitor C1 is connected to the source of the N-channel MOS tube Q1, the other end of the capacitor C1 is connected to the input end of the Schmitt trigger N1, the output end of the Schmitt trigger N1 is connected to the signal input end of the micro control unit, and the input end of the Schmitt trigger N1 is also connected to a resistor R4 and a resistor R5, the other end of the resistor R4 is connected to a power supply VCC, and the other end of the resistor R5 is grounded; In step 2), by adjusting the resistance values ​​of the resistor R5 and the resistor R4, the reference level input to the Schmitt trigger N1 is between the reference levels VH+ and VH-, and the pulse-type exponential decay signal output by the GM counter is filtered by the capacitor C1, superimposed on the reference level, and then input to the input end of the Schmitt trigger N1.

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