CN218728088U - Large-diameter efficient azimuth natural gamma detector - Google Patents
Large-diameter efficient azimuth natural gamma detector Download PDFInfo
- Publication number
- CN218728088U CN218728088U CN202123364403.9U CN202123364403U CN218728088U CN 218728088 U CN218728088 U CN 218728088U CN 202123364403 U CN202123364403 U CN 202123364403U CN 218728088 U CN218728088 U CN 218728088U
- Authority
- CN
- China
- Prior art keywords
- tube
- gamma
- gamma detector
- scaler
- preamplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Measurement Of Radiation (AREA)
Abstract
The invention relates to a large-diameter high-efficiency azimuth natural gamma detector which comprises a G-M counting tube, a high-voltage generator, a preamplifier, a pulse amplifier and a scaler. The G-M counting tubes are uniformly arranged at intervals of 15 degrees and used for monitoring gamma radiation quantity in a 30-degree position, a tungsten filament is tensioned at the center in a thin-wall iron-nickel alloy tube and used as an anode, platinum is sprayed and attached to the inner surface of the tube and used as a cathode, and argon is filled in the tube. The gamma detector used by the invention is a Gegmiller tube, and compared with a gamma logging instrument PTM mainly used in the current logging-while-drilling, the gamma detector has the advantages of small diameter, low plateau area voltage, low power consumption and strong shock resistance, can realize the parallel connection of multiple tubes, and is suitable for near-drilling gamma measurement while drilling. The G-M tube has large diameter and large cathode surface area, the cathode material adopts platinum, the anode adopts thickened tungsten wires, and the thickened tungsten wires are connected with each amplifier and the calibrator at the back, thereby effectively improving the detection efficiency and detecting the natural gamma which cannot be detected by the conventional gamma detector.
Description
The technical field is as follows:
the invention relates to a gamma detector for near-drilling while drilling, in particular to a large-diameter efficient azimuth natural gamma detector.
Background art:
the gamma logging instrument mainly used in the current logging while drilling is PTM (polymer transfer model), namely the combination of a sodium iodide crystal and a photomultiplier, but the diameter of the gamma logging instrument is large, so that the small instrument is difficult to use, the plateau area voltage is high and is about 1500V, the power consumption is high, and the shock resistance is poor. The Geiger-Miller counter tube (GM tube for short) has small diameter, low plateau voltage, low power consumption, high output pulse signal amplitude and high signal-to-noise ratio, and the connected electronic circuit is simple and stable in operation. The shape of the device can be changed, the environmental adaptability is strong, and the device can work under severe conditions of high temperature, low temperature, impact, vibration and the like. Easy manufacture and low cost. Therefore, the method is suitable for near-drilling natural gamma measurement while drilling.
However, when the G-M counter tube is used to detect gamma radiation, the detection efficiency is very low, only about 1%, and the detection efficiency referred to herein is the "ratio of the number of pulses output by the detector to the number of particles entering the sensitive volume of the detector". Furthermore, the narrow range of the G-M tube is also a disadvantage, and the range is typically only three to four orders of magnitude.
The invention content is as follows:
the invention aims to design a gamma detector for near-drilling so as to solve the problems in the prior art.
In order to achieve the above object, the present invention provides the following technical solutions.
A large-diameter high-efficiency azimuth natural gamma detector comprises G-M tubes, a high-voltage generator, a preamplifier, a pulse amplifier and a scaler, wherein the G-M tubes are formed by connecting 3G-M tubes in parallel and are uniformly arranged at intervals of 15 degrees, anodes of the G-M tubes are connected with the high-voltage generator and the preamplifier, the high-voltage generator is fixed in a drill bit and is connected with the anodes of the G-M tubes through a resistor R, and the preamplifier, the pulse amplifier and the scaler are arranged on a circuit board which is fixed in the drill bit.
As a further improvement of the invention, the G-M tube adopts chromium metal as a tube body, a thickened tungsten wire is tensioned at the center of the tube body to be used as an anode, the inner surface of the G-M tube is sprayed with platinum metal to be used as a cathode, and the tube is filled with argon gas with the pressure of about 10cm Hg.
As a further improvement of the invention, the anode of the G-M tube is connected with a preamplifier through a capacitor.
As a further improvement of the invention, the output end of the preamplifier is connected with a pulse amplifier.
As a further improvement of the invention, the output end of the pulse amplifier is connected with a scaler.
As a further improvement of the invention, V + provides reference voltage for the scaler through resistance voltage division, and the output of the scaler is connected with the pulse counter.
As a further improvement of the invention, the preamplifier, the pulse amplifier and the scaler are all on a circuit board, and the circuit board is fixed in the drill bit.
As a further improvement of the invention, the G-M tube adopts the metal chromium as the tube body material, so that the radioactive elements of the counting tube material can be eliminated, the lower limit of measurement is effectively reduced, and the measuring range of the G-M tube is widened.
As a further improvement of the invention, the G-M tubes adopt 3G-M tubes which are connected in parallel and are uniformly arranged at intervals of 15 degrees, thereby effectively improving the upper limit of measurement and widening the measuring range of the G-M tubes.
As a further improvement of the invention, the tube body of the G-M tube has a large diameter, so that the effective area of the cathode is enlarged, and the detection efficiency of the G-M tube is improved.
As a further improvement of the invention, the G-M tube adopts a thickened tungsten wire as an anode, so that the diameter of the anode is increased, and the detection efficiency of the G-M tube is improved.
As a further improvement of the invention, the cathode material of the inner wall of the G-M tube adopts metal platinum, so that the section of the photoelectric effect of the medium and low energy sections is greatly improved, and the detection efficiency of the medium and low energy sections is improved by several times.
As a further improvement of the invention, the high voltage generator recovers the anode potential by charging the counter tube with a resistor R, resulting in a negative voltage pulse at the anode.
As a further improvement of the invention, the preamplifier is connected with the anode of the G-M tube, so that the signal-to-noise ratio of the system is improved, and the relative influence of external interference is reduced.
As a further improvement of the invention, the input of the pulse amplifier is connected with the output of the preamplifier, and the negative voltage pulse of the anode is amplified.
As a further improvement of the invention, the input of the scaler is connected to the output of the pulse amplifier, which is essentially a comparator, the reference voltage is provided by dividing the voltage by a resistor, and when the input voltage is greater than the reference voltage, the pulse counter counts up by one, indicating that a gamma particle is incident.
Compared with a gamma logging instrument PTM mainly used in the current logging-while-drilling, the gamma detector used in the invention is a Gegmiller tube, has small diameter, low plateau area voltage of about 900V, low power consumption and strong shock resistance, can realize the parallel connection of multiple tubes, and is suitable for near-drilling gamma measurement while drilling. The G-M tube has large diameter and large cathode surface area, the cathode material adopts platinum, the anode adopts thickened tungsten wires, and the thickened tungsten wires are connected with each amplifier and the calibrator at the back.
Description of the drawings:
FIG. 1 is a schematic diagram of the present invention.
In the figure: G-M pipe 1, high voltage generator 2, preamplifier 3, pulse amplifier 4, scaler 5.
The specific implementation mode is as follows:
the technical solutions in the embodiments of the present invention will be eliminated and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
As shown in figure 1, a large-diameter high-efficiency azimuth natural gamma detector comprises G-M tubes 1, a high-voltage generator 2, a preamplifier 3, a pulse amplifier 4 and a scaler 5, wherein 3G-M tubes 1 are connected in parallel, when gamma particles enter any G-M tube 1, avalanche is caused in the tube, avalanche discharge reduces the anode potential of the G-M tube 1, meanwhile, the high-voltage generator 2 charges a counting tube through a resistor R to recover the anode potential, a negative voltage pulse is obtained on the anode, the negative voltage pulse is amplified through the preamplifier 3, and the preamplifier 3 mainly has the effects of improving the signal-to-noise ratio and reducing the relative influence of external interference. The voltage pulse passing through the preamplifier 3 is amplified through the pulse amplifier 4, the amplified signal is input into the scaler 5 to be compared with the reference voltage of the scaler 5, the reference voltage of the scaler 5 is obtained through resistance voltage division, when the amplified pulse signal is higher than the reference voltage of the scaler 5, the scaler 5 outputs low level, the counting of the pulse counter is increased by one, which indicates that one gamma particle is incident, and when any one of the 3G-M tubes 1 has the gamma particle incident, the counting of the pulse counter is increased by one, so that the natural gamma radiation can be effectively detected.
The working principle of the G-M pipe is as follows: when the G-M tube 1 works, the direct current high voltage on the anode is supplied by a high-voltage power supply, so that a columnar symmetrical electric field is formed in the counting tube, charged particles enter the counting tube and collide with gas molecules in the tube, and the gas molecules are ionized, namely initially ionized. The electrons generated by the initial ionization move to the anode under the acceleration of an electric field, and simultaneously obtain energy, when the energy is increased to a certain value, gas molecules can be ionized to generate new ion pairs, electrons in the new ion pairs are accelerated to generate ionization collision again in the electric field to generate more ion pairs, because the electric field in a small area near the anode is strongest, the probability of the ionization collision in the area is the largest, so that a large number of electrons and positive ions are multiplied, the phenomenon is called avalanche. Then, the positive ion sheath slowly moves to the cathode under the action of the electric field, and the electric field is weaker and weaker in the process, so that the positive ion sheath can only exchange charges with quenching gas with low ionization potential and is neutralized, and the positive ion sheath can not give out electrons on the cathode, thereby avoiding secondary avalanche. And during the avalanche process, the ultraviolet photons emitted by the de-excitation of the excited atoms and the recombination of positive and negative ions are also absorbed by the polyatomic quenching gas. Thus, one particle incident can only cause one avalanche. The counting tube can be regarded as a capacitor, high voltage is applied before avalanche discharge, so that a certain amount of electric charge exists on two electrodes, electrons neutralize part of electric charge on an anode after discharge, the potential of the anode is reduced, the high-voltage power supply charges the counting tube through a resistor R along with the movement of positive ions to a cathode, the potential of the anode is recovered, and a negative voltage pulse is obtained on the anode.
Claims (6)
1. A large-diameter high-efficiency azimuth natural gamma detector comprises G-M tubes (1), a high-voltage generator (2), a preamplifier (3), a pulse amplifier (4) and a scaler (5), and is characterized in that the G-M tubes (1) are connected in parallel at intervals of 15 degrees, anodes of the G-M tubes are connected with the high-voltage generator (2) and the preamplifier (3), the high-voltage generator (2) is fixed in a drill and connected with the anodes of the G-M tubes through a resistor R, the preamplifier (3), the pulse amplifier (4) and the scaler (5) are all arranged on a circuit board, and the circuit board is fixed in the drill.
2. A large diameter high efficiency azimuthal natural gamma ray detector as claimed in claim 1, wherein G-M tube (1) is made of chromium metal as tube body, a thickened tungsten wire is tensioned at the center as anode, platinum is sprayed on the inner surface of G-M tube as cathode, and argon gas with pressure of about 10cm hg is filled in the tube.
3. A large diameter high efficiency azimuthal natural gamma detector according to claim 2, wherein the G-M tube (1) anode is connected to a preamplifier (3) through a capacitor.
4. A large diameter high efficiency azimuthal natural gamma detector according to claim 3, characterized in that the output of the preamplifier (3) is connected to a pulse amplifier (4).
5. A large diameter high efficiency azimuthal natural gamma detector according to claim 4, wherein the output of the pulse amplifier (4) is connected to a scaler (5).
6. A large diameter high efficiency azimuth natural gamma detector according to claim 5, wherein the reference voltage is provided to the scaler (5) by resistor voltage division, and the output of the scaler (5) is connected to the pulse counter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123364403.9U CN218728088U (en) | 2021-12-30 | 2021-12-30 | Large-diameter efficient azimuth natural gamma detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123364403.9U CN218728088U (en) | 2021-12-30 | 2021-12-30 | Large-diameter efficient azimuth natural gamma detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218728088U true CN218728088U (en) | 2023-03-24 |
Family
ID=85581036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123364403.9U Active CN218728088U (en) | 2021-12-30 | 2021-12-30 | Large-diameter efficient azimuth natural gamma detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218728088U (en) |
-
2021
- 2021-12-30 CN CN202123364403.9U patent/CN218728088U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Colli | Ultraviolet photons in the decay of metastable argon atoms | |
| CN102565846B (en) | Honeycomb-type thermal neutron detector | |
| CN103984001A (en) | Method and device for improving detection sensitivity of static collecting method emanometer | |
| CN1952689A (en) | scintillation activity meter | |
| US2681416A (en) | Neutron scintillation counter | |
| CN105092690A (en) | Ionization absorption spectrum detection device based on multi-channel electron multiplier | |
| CN218728088U (en) | Large-diameter efficient azimuth natural gamma detector | |
| Saito et al. | Simultaneous measurements of absolute numbers of electrons and scintillation photons produced by 5.49 MeV alpha particles in rare gases | |
| CN117607241A (en) | Alpha particle ionization chamber and method for reducing radon and daughter background thereof | |
| CN210376707U (en) | Ray alarm | |
| CN206515476U (en) | A kind of neutron tube | |
| CN101644688B (en) | Sand-measuring ionization chamber | |
| CN212515062U (en) | Neutron detection device for laser inertial confinement fusion | |
| CN106680863A (en) | Neutron tube | |
| WO2017068648A1 (en) | Neutron detector, neutron detection device, and neutron detection system | |
| RU91567U1 (en) | GAS DETECTOR FOR REGISTRATION OF SLOW AND FAST NEUTRONS IN THE CONDITIONS OF INTENSE EXTERNAL RADIATION | |
| RU2414725C1 (en) | Method of detecting slow and fast neutrons in intense external radiation conditions | |
| CN218917656U (en) | Radiation-resistant ionization chamber detector under strong radiation environment | |
| Wittenburg | Beam loss detection | |
| Alfonsi et al. | Advances in fast multi-GEM-based detector operation for high-rate charged-particle triggering | |
| CN204537984U (en) | A kind of multilayer fission chamber device being used for (n, xn) section gauge | |
| CN103675884B (en) | A kind of method for judging that in G-M counter tube nuclear radiation detector, G-M counter tube is saturated | |
| Aoyama et al. | Windowless air proportional counters for detecting tritium β-rays | |
| US4158774A (en) | Radiation detector with improved performance characteristics | |
| Abazov et al. | Comparative analysis of the performance characteristics of mini-drift tubes with different design |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |