Soil low-energy gamma nuclide three-dimensional distribution in-situ measurement system

Abstract

The invention discloses a soil low-energy gamma nuclide three-dimensional distribution in-situ measurement system which comprises a CZT array probe, a ground integration unit and a measurement control remote control terminal. According to the soil low-energy gamma nuclide three-dimensional distribution in-situ measurement system, a CZT array probe comprises a crystal array, a pre-amplifier and a shielding and guiding structure, a ground integration unit comprises a multi-channel data acquisition module, a comprehensive control module, a hoisting device, a communication module, an industrial personal computer and a battery pack, and a measurement control remote control terminal is a notebook computer. A communication module is arranged in the notebook computer, measurement and control software is installed on the notebook computer, the CZT array probe is connected to a hanging device of the ground integrated unit, and the measurement control remote control terminal is remotely connected with the ground integrated unit through the communication module. Measurement of low-energy gamma nuclides in the polluted sandy soil in the depth direction and the horizontal direction is achieved, the three-dimensional distribution measurement capacity is formed, and powerful technical support is provided for radioactive pollution source item investigation.

Description

Technical Field

[0001] The invention relates to the technical field of soil measurement, in particular to an in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil. Background Art

[0002] Environmental surveys are the basic information required for radioactive pollution control. The gamma rays emitted by some radioactive nuclides in the soil have low energy and are difficult to penetrate the soil, so the distribution measurement of these nuclides is a difficult problem. The method of drilling sampling measurement can achieve the measurement of samples, but it faces problems such as sample processing, transportation, and storage. The use of on-site gamma spectrometer measurement combined with the peak-to-valley ratio method can also provide information on the distribution of radioactive nuclides in the soil, but it is only suitable for measuring medium and high energy gamma rays. Therefore, a soil low-energy gamma nuclide three-dimensional distribution in-situ measurement system is proposed to provide strong technical support for the investigation of radioactive pollution sources. Summary of the invention

[0003] The object of the present invention is to provide an in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A soil low-energy gamma nuclide three-dimensional distribution in-situ measurement system comprises a CZT array probe, a ground integrated unit, and a measurement control remote control terminal. The CZT array probe comprises a crystal array, a preamplifier, and a shielding and guiding structure. The ground integrated unit comprises a multi-channel data acquisition module, an integrated control module, a hanging device, a communication module, an industrial computer, and a battery pack. The measurement control remote control terminal is a laptop computer with a built-in communication module and measurement and control software installed on the laptop computer. The CZT array probe is connected to the hanging device of the ground integrated unit, and the measurement control remote control terminal is remotely connected to the ground integrated unit via the communication module.

[0006] As a further solution of the present invention: the measuring method steps are as follows:

[0007] Step 1: Establish a model, based on the physical model of MCNP simulation calculation established by CZT array probe structure;

[0008] Step 2: Operation implementation: Use engineering machinery to drill a hole at the location to be measured, with a diameter of ≥8cm, set up the measurement system above the hole, place the detector in the hole through the hanging device, and gradually lower the detector to the bottom of the hole through the "measurement-lowering" cycle to complete the three-dimensional distribution measurement of low-energy gamma nuclides around the entire hole;

[0009] Step 3: Calculation of nuclide activity: Divide the soil around the small hole into multiple different blocks, and use an array of detectors with the same number of blocks for measurement. According to the net count rate of the full energy peak of the γ energy spectrum of the nuclide of interest measured by each sub-detector, calculate the activity of the nuclide of interest in each block, and obtain its spatial distribution in the soil around the small hole. The calculation formula is as follows:

[0010]

[0011] As a further solution of the present invention: i is the activity of the nuclide of interest in the ith block, in Bq; P γ is the probability of the nuclide emitting characteristic γ rays; ε ij N is the detection efficiency of the jth sub-detector for the characteristic γ-rays of the nuclide of interest in the i-th block; j It is the net count rate of the characteristic gamma-ray full-energy peak of the nuclide of interest in the gamma energy spectrum measured by the j-th sub-detector, in cps.

[0012] As a further solution of the present invention: the preamplifier is installed in the crystal array, and the shielding and guiding structure includes an upper shielding guiding structure and a lower shielding guiding structure, and the upper shielding guiding structure and the lower shielding guiding structure are respectively installed at the upper end and the lower end of the crystal array.

[0013] As a further solution of the present invention: the hanging device includes a cabinet, the battery pack is installed in the cabinet, a mounting frame is placed on the cabinet, a control box is installed on the front side of the mounting frame, an industrial computer is installed on the control box, a multi-channel data acquisition module, an integrated control module and a communication module are installed together on the industrial computer, a traction device is installed at the bottom of the rear side of the mounting frame, a clamping device is installed at the top of the rear side of the mounting frame, a guide roller is installed on the side of the mounting frame through the rotation of the support arm, an encoder is installed on the support arm corresponding to the guide roller, the guide roller is fixedly connected to the rotating shaft end of the encoder, a traction rope is clamped between the traction device and the clamping device, and one end of the traction rope passes around the guide roller and is connected to the CZT array probe.

[0014] As a further solution of the present invention: a pressing roller is installed at the bottom of the pressing device.

[0015] As a further solution of the present invention: a tension adjustment component is installed on the traction device, and the traction device is driven by a motor, a reducer, a sprocket and a chain, and the motor and the reducer are installed in a control box.

[0016] As a further solution of the present invention: the four bottom corners of the cabinet are all equipped with adjustable legs, and a main control measurement board is installed in the cabinet.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention realizes the measurement of low-energy gamma nuclides in the depth and horizontal directions of contaminated sand and soil through the "drilling + in-situ measurement" method, forms a three-dimensional distribution measurement capability, and provides strong technical support for the investigation of radioactive pollution sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a first embodiment of an in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil.

[0020] Figure 2 This is a side internal view of the hanging device in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0021] Figure 3 This is a partial structural diagram of the overhead view of the hanging device in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0022] Figure 4 This is a schematic diagram of the crystal array in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0023] Figure 5 This is a schematic diagram of the crystal array structure interface in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0024] Figure 6 This is a diagram showing the dimensions of the shielding and guiding structure in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0025] Figure 7 This is the physical model diagram of the MCNP simulation calculation in Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0026] Figure 8 This is the connection block diagram of Example 1 of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0027] Fig. 9 This is a diagram showing the second embodiment of the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil.

[0028] In the figure: 1. cabinet; 2. mounting frame; 3. control box; 4. traction device; 5. clamping device; 6. support arm; 7. guide roller; 8. encoder; 9. traction rope; 10. clamping roller; 11. tension adjustment assembly; 12. motor; 13. reducer; 14. sprocket; 15. chain; 16. adjustment leg; 17. main control measurement board. DETAILED DESCRIPTION

[0029] 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.

[0030] Embodiment 1:

[0031] See also Figures 1 to 8 In an embodiment of the present invention, the in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil includes a CZT array probe and a ground integrated unit. The CZT array probe includes a crystal array, a preamplifier, a shielding and guiding structure, and the ground integrated unit includes a multi-channel data acquisition module, an integrated control module, a hanging device, a communication module, an industrial computer and a battery pack. The CZT array probe is connected to the hanging device of the ground integrated unit, and the ground integrated unit and the CZT probe independently complete the measurement work.

[0032] The measurement method steps are as follows:

[0033] Step 1: Establish a model, based on the physical model of MCNP simulation calculation established by CZT array probe structure;

[0034] Step 2: Operation implementation: Use engineering machinery to drill a hole at the location to be measured, with a diameter of ≥8cm, set up the measurement system above the hole, place the detector in the hole through the hanging device, and gradually lower the detector to the bottom of the hole through the "measurement-lowering" cycle to complete the three-dimensional distribution measurement of low-energy gamma nuclides around the entire hole;

[0035] Step 3: Calculation of nuclide activity: Divide the soil around the small hole into multiple different blocks, and use an array of detectors with the same number of blocks for measurement. According to the net count rate of the full energy peak of the γ energy spectrum of the nuclide of interest measured by each sub-detector, calculate the activity of the nuclide of interest in each block, and obtain its spatial distribution in the soil around the small hole. The calculation formula is as follows:

[0036]

[0037] A i is the activity of the nuclide of interest in the ith block, in Bq; P γ is the probability of the nuclide emitting characteristic γ rays; ε ij N is the detection efficiency of the jth sub-detector for the characteristic γ-rays of the nuclide of interest in the i-th block; j It is the net count rate of the characteristic gamma-ray full-energy peak of the nuclide of interest in the gamma energy spectrum measured by the j-th sub-detector, in cps.

[0038] The preamplifier is installed in the crystal array, and the shielding and guiding structure comprises an upper shielding guiding structure and a lower shielding guiding structure, which are respectively installed at the upper end and the lower end of the crystal array.

[0039] The hanging device includes a cabinet 1, a battery pack is installed in the cabinet 1, a mounting frame 2 is placed on the cabinet 1, a control box 3 is installed on the front side of the mounting frame 2, an industrial computer is installed on the control box 3, a multi-channel data acquisition module, an integrated control module and a communication module are installed on the industrial computer together, a traction device 4 is installed on the bottom of the rear side of the mounting frame 2, a clamping device 5 is installed on the top of the rear side of the mounting frame 2, a guide roller 7 is installed on the side of the mounting frame 2 through a support arm 6 for rotation, an encoder 8 is installed on the support arm 6 corresponding to the guide roller 7, the guide roller 7 is fixedly connected to the rotating shaft end of the encoder 8, a traction rope 9 is clamped between the traction device 4 and the clamping device 5, and one end of the traction rope 9 is connected to the CZT array probe by passing around the guide roller 7.

[0040] A pressing roller 10 is installed at the bottom of the pressing device 5 .

[0041] A tension adjustment assembly 11 is installed on the traction device 4 . The traction device 4 is driven by a motor 12 , a reducer 13 , a sprocket 14 and a chain 15 . The motor 12 and the reducer 13 are installed in the control box 3 .

[0042] Adjustable legs 16 are installed at the four corners of the bottom of the cabinet 1 , and a main control measurement board 17 is installed in the cabinet 1 .

[0043] Embodiment 2:

[0044] See also Fig. 9 In an embodiment of the present invention, an in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil includes a CZT array probe, a ground integrated unit, and a measurement control remote control terminal. The CZT array probe includes a crystal array, a preamplifier, and a shielding and guiding structure. The ground integrated unit includes a multi-channel data acquisition module, an integrated control module, a hanging device, a communication module, an industrial computer, and a battery pack. The measurement control remote control terminal is a laptop computer with a built-in communication module. The laptop computer is installed with measurement and control software. The CZT array probe is connected to the hanging device of the ground integrated unit, and the measurement control remote control terminal is remotely connected to the ground integrated unit through the communication module.

[0045] The measurement method steps are as follows:

[0046] Step 1: Establish a model, based on the physical model of MCNP simulation calculation established by CZT array probe structure;

[0047] Step 2: Operation implementation: Use engineering machinery to drill a hole at the location to be measured, with a diameter of ≥8cm, set up the measurement system above the hole, place the detector in the hole through the hanging device, and gradually lower the detector to the bottom of the hole through the "measurement-lowering" cycle to complete the three-dimensional distribution measurement of low-energy gamma nuclides around the entire hole;

[0048] Step 3: Calculation of nuclide activity: Divide the soil around the small hole into multiple different blocks, and use an array of detectors with the same number of blocks for measurement. According to the net count rate of the full energy peak of the γ energy spectrum of the nuclide of interest measured by each sub-detector, calculate the activity of the nuclide of interest in each block, and obtain its spatial distribution in the soil around the small hole. The calculation formula is as follows:

[0049]

[0050] A i is the activity of the nuclide of interest in the ith block, in Bq; P γ is the probability of the nuclide emitting characteristic γ rays; ε ij N is the detection efficiency of the jth sub-detector for the characteristic γ-rays of the nuclide of interest in the i-th block; j It is the net count rate of the characteristic gamma-ray full-energy peak of the nuclide of interest in the gamma energy spectrum measured by the j-th sub-detector, in cps.

[0051] The preamplifier is installed in the crystal array, and the shielding and guiding structure comprises an upper shielding guiding structure and a lower shielding guiding structure, which are respectively installed at the upper end and the lower end of the crystal array.

[0052] The hanging device includes a cabinet 1, a battery pack is installed in the cabinet 1, a mounting frame 2 is placed on the cabinet 1, a control box 3 is installed on the front side of the mounting frame 2, an industrial computer is installed on the control box 3, a multi-channel data acquisition module, an integrated control module and a communication module are installed on the industrial computer together, a traction device 4 is installed on the bottom of the rear side of the mounting frame 2, a clamping device 5 is installed on the top of the rear side of the mounting frame 2, a guide roller 7 is installed on the side of the mounting frame 2 through a support arm 6 for rotation, an encoder 8 is installed on the support arm 6 corresponding to the guide roller 7, the guide roller 7 is fixedly connected to the rotating shaft end of the encoder 8, a traction rope 9 is clamped between the traction device 4 and the clamping device 5, and one end of the traction rope 9 is connected to the CZT array probe by passing around the guide roller 7.

[0053] A pressing roller 10 is installed at the bottom of the pressing device 5 .

[0054] A tension adjustment assembly 11 is installed on the traction device 4 . The traction device 4 is driven by a motor 12 , a reducer 13 , a sprocket 14 and a chain 15 . The motor 12 and the reducer 13 are installed in the control box 3 .

[0055] Adjustable legs 16 are installed at the four corners of the bottom of the cabinet 1 , and a main control measurement board 17 is installed in the cabinet 1 .

[0056] The working principle of the present invention is:

[0057] During use, according to the physical model of MCNP simulation calculation established by the CZT array probe structure, a hole is drilled at the position to be measured by engineering machinery with a diameter ≥ 8 cm. The drilling position should be representative; the hole should be drilled as vertically as possible; the measurement system is set up above the hole, and the system placement area should be as flat as possible. The detector is placed in the hole through a hanging device, and the detector is gradually lowered to the bottom of the hole through a "measurement-lowering" cycle to complete the three-dimensional distribution measurement of low-energy γ nuclides around the entire hole. The soil around the small hole is divided into multiple different blocks, and an array is formed using the same number of detectors as the number of blocks for measurement. The activity of the nuclide of interest in each block is calculated based on the net count rate of the full-energy peak of the γ energy spectrum of the nuclide of interest measured by each sub-detector, and its spatial distribution in the soil around the small hole is obtained. During measurement, the operator chooses whether to remotely control the operation through the communication module according to the situation; before and after daily use of the system, the performance of the system should be checked, mainly focusing on the change in the peak position of the full-energy peak of the energy spectrum.

[0058] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The in-situ measurement system for the three-dimensional distribution of low-energy gamma nuclides in soil includes a CZT array probe, a ground integrated unit, and a measurement control remote control terminal, and is characterized by: The CZT array probe includes a crystal array, a preamplifier, a shielding and guiding structure, the ground integrated unit includes a multi-channel data acquisition module, an integrated control module, a hanging device, a communication module, an industrial computer and a battery pack, the measurement control remote control terminal is a laptop computer, the laptop computer has a built-in communication module, and the laptop computer is installed with measurement and control software, the CZT array probe is connected to the hanging device of the ground integrated unit, and the measurement control remote control terminal is remotely connected to the ground integrated unit through the communication module.

2. The in-situ measurement method for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 1, characterized in that: The measuring method steps are as follows: Step 1: Establish a model, based on the physical model of MCNP simulation calculation established by CZT array probe structure; Step 2: Operation implementation: Use engineering machinery to drill a hole at the location to be measured, set up the measurement system above the hole, place the detector in the hole through the hanging device, and gradually lower the detector to the bottom of the hole through the "measurement-lowering" cycle to complete the three-dimensional distribution measurement of low-energy gamma nuclides around the entire hole; Step 3: Calculation of nuclide activity: Divide the soil around the small hole into multiple different blocks, and use an array of detectors with the same number of blocks for measurement. According to the net count rate of the full energy peak of the γ energy spectrum of the nuclide of interest measured by each sub-detector, calculate the activity of the nuclide of interest in each block, and obtain its spatial distribution in the soil around the small hole. The calculation formula is as follows:

3. The in-situ measurement method for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 2, characterized in that: The A i is the activity of the nuclide of interest in the ith block; P γ is the probability of the nuclide emitting characteristic γ rays; ε ij N is the detection efficiency of the jth sub-detector for the characteristic γ-rays of the nuclide of interest in the i-th block; j is the net count rate of the characteristic gamma-ray full-energy peak of the nuclide of interest in the gamma energy spectrum measured by the jth sub-detector.

4. The in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 1, characterized in that: The preamplifier is installed in the crystal array, and the shielding and guiding structure comprises an upper shielding guiding structure and a lower shielding guiding structure, which are respectively installed at the upper end and the lower end of the crystal array.

5. The in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 1, characterized in that: The hanging device comprises a cabinet (1), a battery pack is installed in the cabinet (1), a mounting frame (2) is placed on the cabinet (1), a control box (3) is installed on the front side of the mounting frame (2), an industrial computer is installed on the control box (3), a multi-channel data acquisition module, an integrated control module and a communication module are installed on the industrial computer, a traction device (4) is installed on the bottom of the rear side of the mounting frame (2), a clamping device (5) is installed on the top of the rear side of the mounting frame (2), a guide roller (7) is rotatably installed on the side of the mounting frame (2) through a support arm (6), an encoder (8) is installed on the support arm (6) corresponding to the guide roller (7), the guide roller (7) is fixedly connected to the rotating shaft end of the encoder (8), a traction rope (9) is clamped between the traction device (4) and the clamping device (5), and one end of the traction rope (9) is passed around the guide roller (7) and connected to the CZT array probe.

6. The in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 5, characterized in that: A pressing roller (10) is installed at the bottom of the pressing device (5).

7. The in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 5, characterized in that: The traction device (4) is provided with a tension adjustment assembly (11). The traction device (4) is driven by a motor (12), a reducer (13), a sprocket (14) and a chain (15). The motor (12) and the reducer (13) are installed in a control box (3).

8. The in-situ measurement system for three-dimensional distribution of low-energy gamma nuclides in soil according to claim 5, characterized in that: Adjustable legs (16) are installed at the four corners of the bottom of the cabinet (1), and a main control measurement board (17) is installed in the cabinet (1).

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