Portable gamma radiation directional detector
Through the lead-free screen-designed light gamma radiation orientation detector, the main and secondary crystal differences are used to eliminate disturbing rays, solving the problems of large weight and poor orientation performance of the existing detectors, and achieving more efficient gamma radiation sampling and cataloging.
Patent Information
- Application Number
- CN201910939245.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-09-30
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2039-09-30
AI Technical Summary
The existing gamma radiation directional detectors have large weight and large volume due to the lead screen, which affects the orientation performance, and the method of removing interfering rays is labor-intensive and has low working efficiency.
Design a lightweight gamma radiation directional detector, adopting a lead-free screen structure, and the combination of cylindrical NaI (TL) and CsI (TL) scintillation crystals and plastic ring scintillation crystals and photomultiplier tubes, to eliminate interference by the difference between the main and secondary crystals Rays affect and improve directional performance.
It realizes the weight of the detector, improves the directional performance, eliminates the backscattering problem caused by lead screens, enhances the directional performance of the gamma radiation directional detector, corrects long-standing technical bias, and provides lighter and more efficient gamma radiation. Sampling and cataloging tools.
Smart Images
Figure CN110609313B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a device for sampling and cataloguing gamma radiation of uranium deposits, in particular to a portable gamma radiation directional detector. Background Art
[0002] The existing γ radiation orientation instrument consists of two parts, one is the γ radiation orientation detector, also called the probe; the other is the operating table, the two are connected by a cable. It is used for γ radiation sampling in mountain projects such as tunnels or trenches, that is, to determine the content and thickness of the ore body based on its γ radiation intensity on the outcrop of the ore body. The orientation instrument can also be used for γ cataloging. The requirements are that the instrument must be light, moisture-proof, and the measurement accuracy and measurement range must meet the requirements.
[0003] The basic characteristic of γ radiation sampling is to try to eliminate the interference of surrounding radiation and accurately measure the γ radiation at the sampling point (see the textbook "Radioactive Method Exploration", Atomic Energy Press, June 1990). To solve this problem, the difference measurement method with lead sleeves was widely used earlier, that is, the detector was wrapped with a lead sleeve with a lead sleeve, and the opening of the lead sleeve that can be used to take and insert the lead bar was aligned with the point. At each measuring point, two values without and with lead bars were measured. The difference does not include the influence of surrounding radiation, and is only related to the radioactive element content and the thickness of the ore layer at the measuring point. This is the secondary measurement method, which is labor-intensive and low in efficiency.
[0004] Since the 1970s, the gamma radiation orientation instrument has been widely used. It is a one-time measurement method. The FD-42 gamma radiation orientation instrument was used in the early days (refer to the textbook "Radiation Exploration Instrument", Department 3 of Chengdu Institute of Geology, Atomic Energy Press, November 1979). The FD-3025A gamma radiation orientation instrument is now used in uranium mines. Both instruments are produced by the 263 Factory of the Nuclear Industry Corporation. Their structures are as follows: Figure 1 As shown, it consists of a housing 1, a main crystal 2, a conical ring lead screen 3, a secondary crystal 4 and a photomultiplier tube 5. They all use waveform analysis technology to distinguish the scintillation pulses of different crystals according to their different luminescence decay times. Although the two instruments mentioned above are decades apart, their probes are both 1.8 kg. The probe is too heavy, and the fundamental reason is that the lead screen 3 is installed. Summary of the invention
[0005] The object of the present invention is to provide a portable gamma radiation directional detector which is used for gamma radiation sampling and cataloguing of uranium deposits and has good directional performance.
[0006] The technical solution for achieving the above-mentioned purpose of the present invention is: a portable gamma radiation directional detector, including a shell, a main crystal, a cylindrical sub-crystal, a donut-shaped sub-crystal and a photomultiplier tube; the main crystal is a cylindrical NaI (TL) scintillation crystal, the cylindrical sub-crystal is a cylindrical CsI (TL) scintillation crystal, and the donut-shaped sub-crystal is a plastic donut-shaped scintillation crystal; the main crystal, the cylindrical sub-crystal and the donut-shaped sub-crystal are coaxially mounted on the end face of the photomultiplier tube in the shell.
[0007] A further technical solution of the present invention is: the main crystal is a cylindrical NaI (TL) scintillating crystal with a diameter of 2.54 cm and a height of 5 cm, and the cylindrical secondary crystal is a cylindrical CsI (TL) scintillating crystal with a diameter of 2.54 cm and a height of 1 cm.
[0008] A further technical solution of the present invention is: the model of the photomultiplier tube is a GDB-23 photomultiplier tube.
[0009] By adopting the above technical solution, the present invention reduces the weight of the gamma radiation directional detector, solves its long-standing unresolved weight problem, and improves its directional performance. Because there is no lead screen, there is no backscattering caused by the lead screen, and the volume and weight of the probe are reduced without the lead screen. Without the lead screen, the crystals can be arranged at the required position. This structure itself constitutes a good gamma radiation directional detector. The auxiliary crystal is installed to record interference rays. The purpose of installing the lead screen in the prior art is to block the interference rays from coming in. The present invention allows the interference rays to come in. After the interference rays come in, they are recorded by the auxiliary crystal. The difference between the main and auxiliary crystals eliminates the influence of the interference rays, so the present invention improves the directional performance of the gamma radiation directional detector. A more important significance of the present invention is to correct a long-standing technical prejudice in the engineering community-gamma radiation directional detectors must be equipped with lead screens. This can be referred to in the two textbooks mentioned above. This prejudice has existed for half a century until today. Lead screens have been used in gamma radiation sampling for nearly a century. It is generally reported that the instrument is heavy and has poor directional performance. However, no other instruments are available, so they have to make do with it. Therefore, the present invention has important reference value for the development of new instruments. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0011] Figure 1 It is a schematic diagram of the structure of an existing gamma radiation directional detector;
[0012] Figure 2 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION Example
[0013] like Figure 2As shown, a portable gamma radiation directional detector includes a housing 6, a main crystal 7, a cylindrical auxiliary crystal 8, a ring-shaped auxiliary crystal 9 and a photomultiplier tube 10.
[0014] The main crystal 7 is a cylindrical NaI (TL) scintillation crystal with a diameter of 2.54 cm and a height of 5 cm, the cylindrical auxiliary crystal 8 is a cylindrical CsI (TL) scintillation crystal with a diameter of 2.54 cm and a height of 1 cm, and the annular auxiliary crystal 9 is a plastic annular scintillation crystal.
[0015] The main crystal 7, the cylindrical auxiliary crystal 8 and the annular auxiliary crystal 9 are coaxially mounted on the end face of the photomultiplier tube 10 in the housing 6. The model of the photomultiplier tube 10 is a GDB-23 photomultiplier tube.
[0016] When in use, the main crystal 7 mainly measures the gamma rays to be detected, and the cylindrical auxiliary crystal 8 and the annular auxiliary crystal 9 mainly measure the surrounding interfering gamma rays. No lead screen is installed inside or outside the probe, that is, it is a lead-free gamma radiation directional detector. The difference between the scintillation pulses of the main and auxiliary crystals is the data to be measured.
Claims
1. A portable gamma radiation directional detector, Its characteristics are Including housing , main crystal, cylindrical sub-crystal, donut-shaped sub-crystal and photomultiplier tube; the main crystal is a cylindrical NaI (TL) scintillation crystal, the cylindrical sub-crystal is a cylindrical CsI (TL) scintillation crystal, and the donut-shaped sub-crystal is a plastic donut-shaped scintillation crystal; the main crystal, cylindrical sub-crystal and donut-shaped sub-crystal are coaxially mounted on the end face of the photomultiplier tube in the outer shell, and no lead screen is installed inside or outside the probe.
2. The portable gamma radiation directional detector according to claim 1, Its characteristics are The main crystal is a cylindrical NaI(TL) scintillation crystal with a diameter of 2.54 cm and a height of 5 cm, and the cylindrical secondary crystal is a cylindrical CsI(TL) scintillation crystal with a diameter of 2.54 cm and a height of 1 cm.
3. The portable gamma radiation directional detector according to claim 1 or 2, Its characteristics are The model of the photomultiplier tube is GDB-23 photomultiplier tube.