CN217606096U - Gegemiller counter signal acquisition circuit - Google Patents

Abstract

The utility model discloses a geiger miller counter signal pickup circuit has increased delay discharge circuit at the output stage, can accelerate to bleed GM pipe negative pole electric charge, has shortened GM pipe circuit dead time. The device specifically comprises a GM tube sampling circuit and a time-delay discharge circuit, wherein the GM tube sampling circuit is connected with a G1 cathode of a GM tube, and an output stage of the GM tube sampling circuit is connected with the time-delay discharge circuit and then connected to a counter, so that the discharge of the cathode charges of the GM tube can be accelerated, and the dead time of the GM tube circuit is shortened. The utility model provides a signal acquisition circuit, output signal width is fixed, is decided by charging resistor R5, charging capacitor C1, carries out dead time matching to different GM pipes; the utility model discloses charge-discharge process can continuous operation when GM pipe transships, and the count rate decline phenomenon can not appear because of transshipping to export fixed frequency signal.

Description

Gegemiller counter signal acquisition circuit

Technical Field

The utility model belongs to the technical field of the counter signal acquisition circuit, concretely relates to geiger miller counter signal acquisition circuit.

Background

At present, radioactive substances and ray devices are widely applied to various fields such as production, scientific research, medical treatment, biology, laboratories and the like, and are used as radioactivity detection instruments, particularly x and gamma personal dose (rate) instruments and x and gamma patrol instruments, and are necessary measurement equipment for radioactivity workers and environmental monitoring of radiation environment places.

The Geiger-Muller counter (GM tube for short) is the most extensive detector for radioactivity measuring instrument, and has the characteristics of small volume, reliable performance, simple acquisition circuit, high cost performance and the like. However, the GM tube has a longer dead time, and is easy to accumulate and block, so that the GM tube has poor linearity in measuring dosage rate, and the dosage rate exceeds a certain level or even shows a value drop.

Most of the existing GM tube signal acquisition circuits adopt the circuit shown in FIG. 1, and an alternating current signal when the GM tube is conducted is acquired through C1. The circuit can not effectively distinguish partial overlapped pulses, so that the dead time of a system is prolonged, and the counting reduction phenomenon can occur when the GM tube is overloaded.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the not enough of prior art, provide a geiger miller counter signal acquisition circuit, specifically adopt following technical scheme:

the utility model provides a geiger miller counter signal acquisition circuit, includes GM pipe sampling circuit and time delay discharge circuit, wherein GM pipe sampling circuit connects GM pipe G1 negative pole, GM pipe sampling circuit output stage inserts the counter after connecting time delay discharge circuit, can accelerate to bleed GM pipe negative pole electric charge, shortens GM pipe circuit dead time.

Further, the GM tube G1 is connected with an anode current limiting resistor R1.

Furthermore, the GM tube sampling circuit comprises a sampling resistor R2, a first switch tube Q1 and a pull-up resistor R3, wherein the cathode of the GM tube G1 is connected with the base electrode of the first switch tube Q1 through the sampling resistor R2; the collector of the first switch tube Q1 is respectively connected with the pull-up resistor R3, the counter Ct and the time-delay discharge circuit, and the emitter of the first switch tube Q1 is grounded.

Further, the time-delay discharge circuit comprises a current-limiting resistor R4, a second switch tube Q2, a charging resistor R5, a charging capacitor C1, a capacitor discharge resistor R6, a grid protection resistor R7, a third switch tube Q3 and a fourth switch tube Q4, the current-limiting resistor R4 is connected between a collector electrode of the first switch tube Q1 and a base electrode of the second switch tube Q2, an emitter electrode of the second switch tube Q2 is connected with a power supply, a collector electrode of the second switch tube Q2 charges the charging capacitor C1 through the charging resistor R5, the charging capacitor C1 is connected to a base electrode of the fourth switch tube Q4, the other end of the charging capacitor C1 is grounded, a grid electrode of the third switch tube Q3 is connected to a collector electrode of the first switch tube Q1 through the grid protection resistor R7, a drain electrode of the third switch tube Q3 is connected with the charging capacitor through the capacitor discharge resistor, a source electrode of the third switch tube Q3 is grounded, the collector electrode of the fourth switch tube Q4 is connected with a cathode of the GM tube G1, and an emitter electrode of the fourth switch tube Q4 is grounded. When gamma rays enter the GM tube G1, gas in the GM tube G1 is ionized and avalanche discharge is caused, charges flow into the base of the first switch tube Q1 through the GM tube sampling resistor R2, the first switch tube Q1 is conducted, the collector of the first switch tube Q1 is lowered to zero potential, the second switch tube Q2 is conducted, the third switch tube Q3 is cut off, the second switch tube Q2 charges the charging capacitor C1 through the charging resistor R5, when the voltage on the charging capacitor C1 rises to the conducting voltage of the fourth switch tube Q4, the fourth switch tube Q4 is conducted, the charges on the cathode of the GM tube G1 are rapidly discharged through the fourth switch tube Q4, the base of the first switch tube Q1 is lowered to zero potential, the first switch tube Q1 is cut off, the collector returns to high level, the second switch tube Q2 is cut off, the charging capacitor C1 is stopped, the third switch tube Q3 is conducted, the fourth switch tube Q4 is cut off, the charging capacitor C1 is discharged from the avalanche transistor Q3 to zero potential through the capacitor discharge resistor R6, the gamma rays enter the GM tube G1 and wait for one-time of gamma ray discharge.

The utility model has the advantages that:

the utility model provides a signal acquisition circuit has increased time delay discharge circuit at the output stage, can accelerate the GM pipe cathode charge of bleeding, has shortened GM pipe circuit dead time, manages dead time and only be conventional circuit third, and the instrument measurement upper limit can improve more than 3 times.

The utility model discloses the output signal width is managed dead time by charging resistor R5, charging capacitor C1 and decides because different model GM is different, and the circuit sets up different times through adjustment R5, C4, realizes carrying out the dead time to the GM and matches.

The utility model discloses charge-discharge process can continuous operation when GM pipe transships, and the count rate decline phenomenon can not appear because of transshipping to export fixed frequency signal.

The utility model discloses the method is simple, by the designer grasp that can be fine and use in the actual design.

Drawings

FIG. 1 shows a conventional GM tube signal acquisition circuit;

FIG. 2 is a circuit diagram of embodiment 1 of the present invention;

reference numerals are as follows: the current-limiting circuit comprises a GM tube G1, an anode current-limiting resistor R1, a sampling resistor R2, a pull-up resistor R3, a current-limiting resistor R4, a charging resistor R5, a capacitor discharging resistor R6, a grid protection resistor R7, a charging capacitor C1, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4 and a counter Ct.

Detailed Description

The conception, specific structure and technical effects of the present invention will be described clearly and completely with reference to the accompanying drawings and embodiments, so as to fully understand the objects, aspects and effects of the present invention. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The same reference numbers will be used throughout the drawings to refer to the same or like parts.

Example 1

The utility model provides a geiger miller counter signal acquisition circuit, realizes with discrete circuit, utilizes discrete passive component preparation to realize GM counter signal acquisition circuit design on the circuit board promptly, and signal output width is fixed, adjustable to can realize GM pipe dead time and match the design, including GM pipe sampling circuit and time delay discharge circuit, wherein GM pipe sampling circuit connects GM pipe G1 negative pole, GM pipe sampling circuit output stage inserts the counter after connecting time delay discharge circuit, can accelerate the bleeder GM pipe cathode charge, shortens GM pipe circuit dead time.

Specifically, the anode of the GM tube G1 is connected to an anode current limiting resistor R1. The GM tube sampling circuit comprises a sampling resistor R2, a first switch tube Q1 and a pull-up resistor R3, and the cathode of the GM tube G1 is connected with the base electrode of the first switch tube Q1 through the sampling resistor R2; the collector of the first switch tube Q1 is respectively connected with a pull-up resistor R3, a counter Ct and a time-delay discharge circuit, the emitter of the first switch tube Q1 is grounded, and the other end of the pull-up resistor R3 is connected with a power supply.

Specifically, the time delay discharge circuit includes current-limiting resistor R4, second switch tube Q2, charging resistor R5, charging capacitor C1, capacitor discharge resistor R6, grid protection resistor R7, third switch tube Q3 and fourth switch tube Q4, be connected current-limiting resistor R4 between first switch tube Q1 collecting electrode and the second switch tube Q2 base, second switch tube Q2 emitter connection power, second switch tube Q2 collecting electrode charges charging capacitor C1 through charging resistor R5, charging capacitor C1 is connected to fourth switch tube Q4 base, charging capacitor C1 other end ground connection, third switch tube Q3 grid is connected to first switch tube Q1 collecting electrode through grid protection resistor R7, third switch tube Q3 drain electrode passes through capacitor discharge resistor and charging capacitor and links to each other, third switch tube Q3 source ground connection, fourth switch tube Q4 collecting electrode and GM tube G1 cathode connection, fourth switch tube Q4 emitter ground connection. When gamma rays enter the GM tube G1, gas in the GM tube G1 is ionized and avalanche discharge is caused, charges flow into the base of the first switch tube Q1 through the GM tube sampling resistor R2, the first switch tube Q1 is conducted, the collector of the first switch tube Q1 is lowered to zero potential, the second switch tube Q2 is conducted, the third switch tube Q3 is cut off, the second switch tube Q2 charges the charging capacitor C1 through the charging resistor R5, when the voltage on the charging capacitor C1 rises to the conducting voltage of the fourth switch tube Q4, the fourth switch tube Q4 is conducted, the charges on the cathode of the GM tube G1 are rapidly discharged through the fourth switch tube Q4, the base of the first switch tube Q1 is lowered to zero potential, the first switch tube Q1 is cut off, the collector returns to high level, the second switch tube Q2 is cut off, the charging capacitor C1 is stopped, the third switch tube Q3 is conducted, the fourth switch tube Q4 is cut off, the charging capacitor C1 is discharged from the avalanche transistor Q3 to zero potential through the capacitor discharge resistor R6, the gamma rays enter the GM tube G1 and wait for one-time of gamma ray discharge. When the GM tube G1 is overloaded, a continuous current flows from the anode a to the cathode K through the GM tube G1, the fourth switching tube Q4 is turned on and off in a gap, and the collector of the first switching tube Q1 outputs a continuous square wave pulse signal.

The test data for the J302GM counter tube used in this example is shown in table one:

from the above table one, it can be seen that: the GM tube with the same model is adopted, the total dead time is only one third of that of a conventional circuit, and the upper limit of the instrument measurement can be improved by more than 3 times.

The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment, and the technical effects of the present invention can be achieved by the same means, which all belong to the protection scope of the present invention. Various modifications and variations of the technical solution and/or the embodiments thereof are possible within the scope of the invention.

Claims (3)

1. The Gegemiller counter signal acquisition circuit is characterized by comprising a GM tube sampling circuit and a delayed discharge circuit, wherein the GM tube sampling circuit is connected with a cathode of a GM tube (G1), and an output stage of the GM tube sampling circuit is connected with the delayed discharge circuit and then connected to a counter (Ct).

2. The Geiger Miller counter signal acquisition circuit according to claim 1, wherein the GM tube sampling circuit comprises a sampling resistor (R2), a first switch tube (Q1) and a pull-up resistor (R3), the cathode of the GM tube (G1) is connected with the base of the first switch tube (Q1) through the sampling resistor (R2); the collector of the first switch tube (Q1) is respectively connected with a pull-up resistor (R3), a counter (Ct) and a time delay discharge circuit, and the emitter of the first switch tube (Q1) is grounded.

3. The Geiger counter signal acquisition circuit according to claim 2, wherein the time delay discharge circuit comprises a current limiting resistor (R4), a second switching tube (Q2), a charging resistor (R5), a charging capacitor (C1), a capacitor discharge resistor (R6), a gate protection resistor (R7), a third switching tube (Q3) and a fourth switching tube (Q4); be connected with current limiting resistor (R4) between first switch tube (Q1) collecting electrode and second switch tube (Q2) base, second switch tube (Q2) projecting pole is connected, second switch tube (Q2) collecting electrode charges charging capacitor (C1) through charging resistor (R5), be connected with grid protection resistance (R7) between third switch tube (Q3) grid and first switch tube (Q1) collecting electrode, be connected electric capacity discharge resistance (R6) between third switch tube (Q3) drain electrode and charging capacitor (C1), third switch tube (Q3) source ground connection, charging capacitor (C1) is connected to fourth switch tube (Q4) base, charging capacitor (C1) other end ground connection, fourth switch tube (Q4) collecting electrode is connected with GM pipe (G1) negative pole, fourth switch tube (Q4) projecting pole ground connection.

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