Automatic low-background alpha and beta detection device

Abstract

The invention belongs to the technical field of nuclear radiation measurement, and particularly relates to an automatic low background alpha and beta detection device. The device comprises a cylindrical lead chamber, a main detector, an anticoincidence detector, a first photomultiplier, a second photomultiplier and a conveying device, the conveying device is arranged on the outer side of the lead chamber and used for conveying a sample to be detected into the cylindrical lead chamber for detection, and the main detector and the anticoincidence detector are located in the cylindrical lead chamber and used for detecting the sample to be detected. The main detector and the anticoincidence detector lead out signals through the first photomultiplier tube and the second photomultiplier tube respectively. The problem of total alpha and total beta radioactivity automatic detection can be solved, and multiple samples can be detected at a time.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear radiation measurement, and in particular relates to an automatic low-background α, β detection device. Background Art

[0002] In nuclear radiation measurement, a large number of samples such as drinking water, domestic sewage, industrial wastewater, soil, sediment, aerosol, biological ash, etc. need to be monitored for total α and total β radioactivity. The low-background α and β measuring instruments currently used can only analyze a small number of samples each time, and staff are required to frequently replace samples and record data regularly. Due to the large number of samples to be analyzed by nuclear facility units every day, the existing technology cannot meet the monitoring needs and cannot maximize the utilization of instruments. In order to improve the laboratory's automated analysis capabilities and save labor costs, a detection device that can automatically detect total α and total β radioactivity is needed to detect multiple samples at one time. Summary of the invention

[0003] The technical problem solved by the present invention is to provide an automatic low-background α and β detection device, which can solve the problem of automatic detection of total α and total β radioactivity and realize detection of multiple samples at one time.

[0004] The technical solution adopted by the present invention is:

[0005] An automatic low-background α, β detection device comprises a cylindrical lead chamber, a main detector, an anti-coincidence detector, a first photomultiplier tube, a second photomultiplier tube, and a transmission device. The transmission device is arranged outside the lead chamber and is used to send a sample to be tested into the cylindrical lead chamber for detection. The main detector and the anti-coincidence detector are located inside the cylindrical lead chamber to detect the sample to be tested. The main detector and the anti-coincidence detector lead out signals through the first photomultiplier tube and the second photomultiplier tube respectively.

[0006] The conveying device consists of a card slot, a roller and a mechanical arm. The card slot is embedded in the crawler of the conveying device, the roller is located below the crawler of the conveying device, and the mechanical arm is located at the center of the conveying device. The card slot and the mechanical arm are both controlled to move by the roller.

[0007] A square slot is provided on the side of the lead chamber, and the position of the square slot corresponds to the position of the robotic arm. The processed sample to be tested is spread flat on the sample tray, placed in the card slot, and transported to the square slot via a conveying device. The robotic arm is used to pick up the sample tray and move it into the lead chamber for α and β detection.

[0008] The lead chamber comprises a lead cover, a lead body, a lead chamber base, a lead chamber fixing device and a metal connecting rod. The lead body and the lead chamber base are located inside the lead chamber fixing device, the lead cover is located above the lead chamber fixing device, and the lead cover and the outer wall of the lead chamber fixing device are connected by a metal connecting rod.

[0009] The lead chamber base is composed of six fan-shaped structures processed from old lead spliced ​​into a circular structure, with a sample support platform at the center. The sample support platform is embedded in the center of the support platform base and can be moved up and down according to program settings. The support platform base is fixed at the center position above the lead chamber base.

[0010] The lead body is formed by splicing three pieces of arc-shaped structures processed from old lead. The interior of the lead body is hollow. A second photomultiplier tube, an anti-coincidence detector and a main detector are arranged inside the lead body. The anti-coincidence detector is attached to the top of the main detector and is coupled to the second photomultiplier tube through silicone oil.

[0011] The main detector adopts a garnet scintillation crystal with the ability to distinguish α and β rays, and the anti-coincidence detector adopts a scintillation crystal with the ability to detect γ rays.

[0012] The scintillation light emitted by the main detector is output from the side through three first photomultiplier tubes. The main detector and the first photomultiplier tubes are connected by a truncated cone-shaped light guide, and the remaining part is covered with a reflective layer. The first photomultiplier tube and the light guide are coupled by silicone oil. The first photomultiplier tube is composed of three photomultiplier tubes of the same model and is used for the main detector signal output, and the second photomultiplier tube is used for the anti-coincidence detector signal output.

[0013] The main detector, reflective layer, light guide, and first photomultiplier tube are all wrapped and fixed by a second supporting structure made of aluminum alloy material. The second supporting structure is a hollow cylinder in the middle and has three hollow cylinders on the side. Three light guides and three first photomultiplier tubes are respectively placed therein. The first supporting structure made of aluminum alloy material supports the three hollow cylinders respectively.

[0014] The lead chamber fixture is made of copper. Four small holes are provided on the side of the lead chamber fixture for leading out the detector signal line. The width and height of the square slot are slightly larger than the robotic arm to facilitate the robotic arm to push the sample tray into the lead chamber.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention provides an automatic low-background α and β detection device, which spreads the processed samples on a sample tray, places them in the card slots in turn, and transmits them to the square slots through a conveyor. A robotic arm is used to place the sample tray above the sample support table inside the lead chamber. The sample support table rises to the bottom of the main detector according to a fixed procedure to perform α and β detection. After the sample detection is completed, the data is automatically recorded, and then the sample support table is controlled to descend to the same horizontal plane as the support table base. The sample tray is taken out by a robotic arm and put back into the card slot, and the conveyor track is moved to repeat the measurement of the next sample, which solves the problem of frequent manual sample replacement. 18 samples can be measured at one time to achieve automatic measurement.

[0017] 2. The present invention provides an automatic low-background α and β detection device, which can effectively reduce the interference caused by cosmic rays in the environment and γ rays in the sample through lead chamber shielding of sufficient thickness and anti-coincidence design; the main detector uses three photomultiplier tubes to collect scintillation light, which can greatly improve the detection efficiency of the detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the front side of the automatic low-background α and β detection device provided by the present invention;

[0019] Figure 2 It is a schematic diagram of the overall structure of the back side of the automatic low-background α and β detection device provided by the present invention;

[0020] Figure 3 It is a schematic diagram of the exploded structure of the lead chamber and detector part of the automatic low-background α and β detection device provided by the present invention;

[0021] Figure 4 It is a schematic diagram of the structure of the light guide and reflective layer of the automatic low-background α and β detection device provided by the present invention;

[0022] Figure 5 It is a schematic diagram of the structure of the fixing device of the lead chamber in the automatic low-background α and β detection device provided by the present invention;

[0023] Figure 6 This is a detailed diagram of the mechanical arm in the automatic low-background α, β detection device provided by the present invention.

[0024] In the figure, 1. lead chamber; 2. small hole; 3. square slot; 4. conveying device; 5. mechanical arm; 6. card slot; 7. roller; 8. lead cover; 9. first supporting structure; 10. second supporting structure; 11. reflecting layer; 12. light guide; 13. first photomultiplier tube; 14. lead body; 15. second photomultiplier tube; 16. anti-coincidence detector; 17. main detector; 18. sample tray; 19. lead chamber base; 20. sample support platform; 21. support platform base; 22. lead chamber fixing device; 23. metal connecting rod. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments 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.

[0026] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] like Figure 1-Figure 6 As shown, an automatic low-background α, β detection device provided by the present invention comprises a cylindrical lead chamber 1, a main detector 17, an anti-coincidence detector 16, a first photomultiplier tube 13, a second photomultiplier tube 15, a first support structure 9, a second support structure 10, a conveyor 4, and a liftable sample support table 20, wherein the conveyor 4 is arranged outside the lead chamber 1, and the conveyor 4 is composed of a card slot 6, a roller 7 and a mechanical arm 5, the card slot 6 is embedded in the crawler of the conveyor 4, the roller 7 is located below the crawler of the conveyor 4, the mechanical arm 5 is located at the center of the conveyor 4, and the card slot 6 and the mechanical arm 5 are both controlled to move by the roller 7; a square slot 3 is provided on the side of the lead chamber 1, and the position of the square slot 3 corresponds to the position of the mechanical arm 5, the processed sample to be tested is flattened in the sample tray 18, placed in the card slot 6, and conveyed to the square slot 3 by the conveyor 4, and the sample tray 18 is picked up and moved into the lead chamber 1 by the mechanical arm 5 for α, β detection;

[0029] The lead chamber 1 comprises a lead cover 8, a lead body 14, a lead chamber base 19, a lead chamber fixing device 22 and a metal connecting rod 23. The lead body 14 and the lead chamber base 19 are located inside the lead chamber fixing device 22, and the lead cover 8 is located above the lead chamber fixing device 22. The lead cover 8 and the outer wall of the lead chamber fixing device 22 are connected by the metal connecting rod 23, so that when a fault occurs in the device, the lead cover can be opened for maintenance;

[0030] The lead chamber base 19 is composed of six fan-shaped structures processed from old lead and spliced ​​into a circular ring structure, with a sample support 20 in the center. The sample support 20 is embedded in the center of the support base 21 and can move up and down according to the program setting. The support base 21 is fixed at the center position above the lead chamber base 19;

[0031] The lead body 14 is formed by splicing three pieces of arc-shaped structures processed from old lead, and is hollow inside. A second photomultiplier tube 15, an anti-coincidence detector 16 and a main detector 17 are arranged inside the lead body 14. The anti-coincidence detector 16 is attached to the top of the main detector 17 and is coupled to the second photomultiplier tube 15 through silicone oil. The main detector 17 uses a garnet scintillation crystal with α and β discrimination capabilities, and the anti-coincidence detector 16 uses a scintillation crystal with γ-ray detection capabilities. The α, β and γ rays generated in the sample all generate signals in the main detector 17, and the γ rays have strong penetrating power and will pass through the main detector 17, while generating signals in the anti-coincidence detector 16. Through electronic signal processing, the γ signal in the main detector 17 is removed by using the anti-coincidence technology, and the remaining α and β signals are pulse-discriminated, and the total α and total β radioactivity measurement results are calculated and displayed respectively;

[0032] The scintillation light emitted by the main detector 17 is output from the side through three first photomultiplier tubes 13. The main detector 17 and the first photomultiplier tubes 13 are connected by a truncated cone-shaped light guide 12, and the remaining part is covered with a reflective layer 11. The first photomultiplier tube 13 and the light guide 12 are coupled by silicone oil to better collect the scintillation light. The first photomultiplier tube 13 is composed of three photomultiplier tubes of the same model, which are used for the signal output of the main detector 17, and the second photomultiplier tube 15 is used for the signal output of the anti-coincidence detector 16.

[0033] The main detector 17, the reflective layer 11, the light guide 12, and the first photomultiplier tube 13 are all wrapped and fixed by the second support structure 10 made of aluminum alloy material. The second support structure 10 is a hollow cylinder in the middle and has three hollow cylinders on the side. The three light guides 12 and the three first photomultiplier tubes 13 are respectively placed therein. The first support structure 9 made of aluminum alloy material supports the three hollow cylinders respectively.

[0034] The lead chamber fixture 22 is made of copper, and four small holes 2 are provided on the side of the lead chamber fixture 22 for leading out the detector signal line. The width and height of the square slot 3 are slightly larger than the robotic arm 5 to facilitate the robotic arm 5 to push the sample tray 18 into the lead chamber 1.

[0035] In this embodiment:

[0036] During operation, the processed samples are spread on the sample tray 18, placed in the card slot 6 in sequence, and transported to the square slot 3 via the conveyor 4. The sample tray 18 is placed on the sample support 20 inside the lead chamber using the robotic arm 5. The sample support 20 rises to the bottom of the main detector 17 according to a fixed procedure to perform α and β detection. After the sample detection is completed, the data is automatically recorded, and then the sample support 20 is controlled to descend to the same level as the support base 21. The sample tray 18 is taken out using the robotic arm 5 and placed back in the card slot 6, and the conveyor crawler is moved to repeat the next sample measurement. After all samples on the conveyor 4 are measured, the samples are uniformly replaced for the next batch of measurements.

[0037] This detection device can place 18 samples at a time to achieve automatic measurement.

[0038] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0039] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An automatic low-background α and β detection device, characterized in that: The invention comprises a cylindrical lead chamber (1), a main detector (17), an anti-coincidence detector (16), a first photomultiplier tube (13), a second photomultiplier tube (15), and a conveying device (4). The conveying device (4) is arranged outside the lead chamber (1) and is used to convey a sample to be tested into the cylindrical lead chamber (1) for testing. The main detector (17) and the anti-coincidence detector (16) are located inside the cylindrical lead chamber (1) to detect the sample to be tested. The main detector (17) and the anti-coincidence detector (16) respectively lead out signals through the first photomultiplier tube (13) and the second photomultiplier tube (15).

2. The automatic low-background α, β detection device according to claim 1, characterized in that: The conveying device (4) is composed of a card slot (6), a roller (7) and a mechanical arm (5); the card slot (6) is embedded in the crawler belt of the conveying device (4); the roller (7) is located below the crawler belt of the conveying device (4); the mechanical arm (5) is located at the center of the conveying device (4); and the card slot (6) and the mechanical arm (5) are both controlled to move by the roller (7).

3. The automatic low-background α, β detection device according to claim 2, characterized in that: The side of the lead chamber (1) is provided with a square slot (3), the position of the square slot (3) corresponds to the position of the mechanical arm (5), the processed sample to be tested is spread on the sample tray (18), placed in the card slot (6), and transported to the square slot (3) via the transport device (4), and the sample tray (18) is picked up by the mechanical arm (5) and moved into the lead chamber (1) for α and β testing.

4. The automatic low-background α, β detection device according to claim 1, characterized in that: The lead chamber (1) comprises a lead cover (8), a lead body (14), a lead chamber base (19), a lead chamber fixing device (22) and a metal connecting rod (23); the lead body (14) and the lead chamber base (19) are located inside the lead chamber fixing device (22); the lead cover (8) is located above the lead chamber fixing device (22); and the lead cover (8) and the outer wall of the lead chamber fixing device (22) are connected via a metal connecting rod (23).

5. The automatic low-background α, β detection device according to claim 4, characterized in that: The lead chamber base (19) is composed of six fan-shaped structures processed from old lead and spliced ​​into a circular ring structure, at the center of which is a sample support platform (20). The sample support platform (20) is embedded in the center of the support platform base (21) and can move up and down according to program settings. The support platform base (21) is fixed at the center position above the lead chamber base (19).

6. The automatic low-background α, β detection device according to claim 4, characterized in that: The lead body (14) is formed by splicing three pieces of arc-shaped structures processed from old lead, and is hollow inside. A second photomultiplier tube (15), an anti-coincidence detector (16) and a main detector (17) are arranged inside the lead body (14). The anti-coincidence detector (16) is attached to the top of the main detector (17) and is coupled to the second photomultiplier tube (15) through silicone oil.

7. The automatic low-background α, β detection device according to claim 6, characterized in that: The main detector (17) uses a garnet scintillation crystal with α and β discrimination capabilities, and the anti-coincidence detector (16) uses a scintillation crystal with γ ray detection capabilities.

8. The automatic low-background α, β detection device according to claim 6, characterized in that: The scintillation light emitted by the main detector (17) is output from the side through three first photomultiplier tubes (13); the main detector (17) and the first photomultiplier tubes (13) are connected by a truncated cone-shaped light guide (12), the remaining part of which is covered by a reflective layer (11); the first photomultiplier tube (13) and the light guide (12) are coupled by silicone oil; the first photomultiplier tube (13) is composed of three photomultiplier tubes of the same model and is used for the main detector (17) signal output; the second photomultiplier tube (15) is used for the anti-coincidence detector (16) signal output.

9. The automatic low-background α, β detection device according to claim 8, characterized in that: The main detector (17), the reflective layer (11), the light guide (12), and the first photomultiplier tube (13) are all wrapped and fixed by a second support structure (10) made of an aluminum alloy material. The second support structure (10) is a hollow cylinder in the middle and has three hollow cylinders on the side. The three light guides (12) and the three first photomultiplier tubes (13) are respectively placed therein. The first support structure (9) made of an aluminum alloy material supports the three hollow cylinders respectively.

10. The automatic low-background α, β detection device according to claim 4, characterized in that: The lead chamber fixing device (22) is made of copper. Four small holes (2) are provided on the side of the lead chamber fixing device (22) for leading out the detector signal line. The width and height of the square slot (3) are slightly larger than the mechanical arm (5) to facilitate the mechanical arm (5) to push the sample tray (18) into the lead chamber (1).

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