Uniform neutron radiation test device based on neutron source array

Abstract

The invention relates to the technical field of nuclear radiation protection, and provides a neutron source array-based uniform neutron radiation test device, which comprises a shielding water body, a polyethylene bracket, a neutron source array, a driving mechanism, a calibration platform and the like, the shielding water body is used for shielding neutron radiation when the device is not used so as to guarantee the safety of operators, the polyethylene support is used for installing the neutron source, the driving mechanism drives the polyethylene support to move, and the neutron source array or the interior of the water body is shielded under the driving of the polyethylene support. Or floating out of the water surface to obtain a uniform neutron radiation field; the calibration platform is used for placing and fixing an instrument to be measured, and the stopping position of the calibration platform can be selected according to the side scale. According to the test device, a relatively large and uniform neutron field can be generated, the distance from the neutron radiation detector meter to the neutron source can be adjusted, and when the detector meter is used for testing, the accuracy is high, and the test result is reliable.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear radiation protection, in particular to a uniform neutron radiation test device based on a neutron source array. Background Art

[0002] Neutron radiation is a significant type of ionizing radiation, and neutron radiation detection instruments are available in a wide variety of types. Currently, testing and calibration of neutron radiation detection instruments often utilizes the radiation field generated by a single, near-point-source standard neutron source. This method, for larger instruments, results in uneven field distribution at the irradiated site due to the instrument's large spatial span. This can lead to significant errors during equipment testing and calibration, severely impacting the accuracy of instrument monitoring data. A few radiation fields created using multiple neutron sources are limited by their methodological limitations and can only calibrate individual standard radiation field intensities. This can easily lead to significant systematic errors and hinder accurate instrument calibration. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a uniform neutron radiation test device based on a neutron source array, which can generate a relatively uniform neutron field of a larger size and adjust the distance between the neutron radiation detection instrument and the neutron source. When testing the detection instrument, the accuracy is high and the test results are reliable.

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

[0005] A uniform neutron radiation test device based on a neutron source array, comprising a shielding water body, a polyethylene support, a neutron source array, a driving mechanism, a calibration platform, etc.;

[0006] The shielding water body is used to shield neutron radiation when the device is not in use to ensure the safety of operators. The shielding water body mainly includes a cement foundation, a cement cover with a lead plate, and water filling the interior of the foundation;

[0007] The polyethylene bracket is used to install the neutron source, and is driven by the driving mechanism to drive the neutron source array upward and downward;

[0008] The neutron source array is composed of a neutron source and a neutron source cladding. The neutron source is encapsulated in the neutron source cladding. The neutron source cladding is installed on a polyethylene bracket through a threaded connection, so that the neutron source protrudes from the bracket, is less affected in the direction of the radiation field, and is more likely to form a uniform radiation field.

[0009] The driving mechanism includes a motor, a screw and a support structure. The motor controls the screw to rotate through a controller, thereby driving the polyethylene bracket to move. Driven by the polyethylene bracket, the neutron source array is either immersed in the water body to be shielded, or floats to the surface to obtain a uniform neutron radiation field.

[0010] The calibration platform is arranged above the shielding water body and in front of the neutron source array. A fixing device is provided above the calibration platform for placing and fixing the instrument to be tested. There are rollers and guide rails under the calibration platform, and the docking position of the calibration platform can be selected according to the side scale.

[0011] In the above technical solution, the neutron source is selected 241 The am-be source has a long half-life, allowing for long-term use and easy maintenance. The number of neutron sources is determined by the required neutron radiation field size through Monte Carlo simulation. To facilitate inverted installation of the neutron sources, they are first installed in the housing and then directly mounted on the polyethylene bracket, significantly minimizing the impact on personnel during the inverted installation process.

[0012] In the above technical solution, the shielding water body adopts water with good neutron slowing down and shielding effect as the shield. In order to shield the gamma rays generated in the neutron slowing down process, a cement foundation of a certain thickness and a cement cover with lead plate are added to the outside of the main water body. The thickness of various materials is determined according to the radiation intensity.

[0013] In the above technical solution, the polyethylene bracket is made of polyethylene and has a corresponding array of threaded holes on one side for mounting the neutron source cladding. While securing the neutron source, it also shields the other side of the neutron radiation field in the direction not used, making the radiation field safer.

[0014] In the above technical solution, the calibration platform includes a table, a guide rail assembly, a translation drive motor, etc., and the platform is guided and moved by the linear guide rail assembly.

[0015] The present invention's uniform neutron radiation test device, based on a neutron source array, offers advantages over existing technologies in that it can generate a relatively uniform neutron radiation field of a larger size, resulting in high accuracy and reliable test results for detection instruments. Furthermore, the use of water as the primary shield reduces construction difficulty and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the device of the present invention when establishing a uniform neutron radiation field.

[0017] Figure 2 This is a schematic diagram of the device of the present invention shielding neutron radiation.

[0018] Figure 3 It is a top view schematic diagram of the device of the present invention.

[0019] Among them: 1. Drive motor, 2. Screw, 3. Polyethylene bracket, 4. Shielding water, 5. Cement cover with lead plate, 6. Calibration platform, 7. Neutron source array, 8. Table, 9. Guide rail assembly, 10. Ruler. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] like Figures 1 to 2 As shown, this embodiment provides a uniform neutron radiation test device based on a neutron source array, including a shielding water body 4, a polyethylene bracket 3, a neutron source array 7, a driving mechanism, a calibration platform 6, etc.

[0022] The shielding water body 4 primarily consists of a cement foundation, a lead-plated cement cover 5, and water filling the foundation. The shielding water body 4 utilizes water with good neutron moderation and shielding properties. To shield against gamma rays generated during the neutron moderation process, a cement foundation and lead-plated cement cover of a certain thickness are added to the exterior of the main water body. The thickness of each material is determined based on radiation intensity.

[0023] The polyethylene bracket 3 is used to mount the neutron source. Driven by a drive mechanism, it drives the neutron source array upward and downward. Made of polyethylene, the polyethylene bracket 3 has threaded holes on one side corresponding to the array for mounting the neutron source cladding. While securing the neutron source, it also shields the other side from the neutron radiation field, ensuring a safer radiation field.

[0024] The neutron source array 7 consists of a neutron source and a neutron source cladding. The neutron source is encapsulated in the neutron source cladding, and the neutron source cladding is installed on a polyethylene bracket through a threaded connection, so that the neutron source protrudes from the bracket, is less affected in the direction of the radiation field, and is more likely to form a uniform radiation field; 14 241Am-Be neutron sources are used to form an array distribution of 2 rows and 7 columns, of which the activity of the 4 neutron sources placed at the two ends is 2Ci, and the activity of the 10 neutron sources in the middle is 1Ci.

[0025] The driving mechanism includes a driving motor 1, a screw 2 and a supporting structure. The motor controls the rotation of the screw through a controller to drive the polyethylene bracket to move. Driven by the polyethylene bracket, the neutron source array is either immersed in the water body to be shielded, or floats to the surface to obtain a uniform neutron radiation field.

[0026] The calibration platform 6 is arranged above the shielding water body 4 and in front of the neutron source array 7. A fixing device is provided above the calibration platform 6 for placing and fixing the instrument to be tested. There are rollers and guide rails under the calibration platform 6. The docking position of the calibration platform can be selected according to the side scale 10. Figure 3As shown, the calibration platform 6 includes a table 8, a guide rail assembly 9, a translation drive motor, etc., and the platform is guided and moved by a linear guide rail 10 assembly.

[0027] The workflow of this embodiment is as follows:

[0028] Before the test begins, the neutron source array is in an underwater shielded position. The instrument to be tested is placed on the calibration platform and secured with a fixture. The calibration platform is adjusted to the desired calibration position according to the scale. The personnel exit the laboratory and, using remote control, the polyethylene bracket guides the neutron source array out of the water to establish the radiation field. The instrument to be tested is then calibrated or calibrated under the standard neutron radiation field. After the test, the polyethylene bracket is remotely lowered into the water to enter the shielded state. The instrument can then be removed and the calibration platform returned to its original position.

[0029] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0030] The above is only an example of the use of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A uniform neutron radiation test device based on a neutron source array, characterized in that: It includes shielding water, polyethylene support, neutron source array, driving mechanism and calibration platform; The shielding water body is used to shield neutron radiation when the device is not in use to ensure the safety of operators. The shielding water body includes a cement foundation, a cement cover with a lead plate, and water filling the interior of the foundation; The polyethylene bracket is used to install the neutron source, and is driven by the driving mechanism to drive the neutron source array upward and downward; The neutron source array comprises a neutron source and a neutron source cladding, wherein the neutron source is encapsulated in the neutron source cladding, and the neutron source cladding is mounted on a polyethylene bracket so that the neutron source protrudes from the bracket; The driving mechanism includes a motor, a screw and a supporting structure. The motor controls the screw to rotate through a controller to drive the polyethylene bracket to move. Driven by the polyethylene bracket, the neutron source array is either immersed in the water body to be shielded, or floats to the surface to obtain a uniform neutron radiation field. The calibration platform is arranged above the shielding water body and in front of the neutron source array. A fixing device is arranged above the calibration platform for placing and fixing the instrument to be tested. There are rollers and guide rails under the calibration platform, and the docking position of the calibration platform can be selected according to the side scale.

2. The uniform neutron radiation test device based on a neutron source array according to claim 1 is characterized in that: The neutron source is selected from 241 The number of am-be sources and neutron sources is determined by the size of the required neutron radiation field through Monte Carlo simulation calculation.

3. The uniform neutron radiation test device based on a neutron source array according to claim 1 or 2, characterized in that: 14 pieces 241 The am-be neutron sources are arranged in an array of 2 rows and 7 columns, with the 4 neutron sources at the two ends having an activity of 2ci each, and the 10 in the middle having an activity of 1ci each.

4. The uniform neutron radiation test device based on a neutron source array according to claim 1 is characterized in that: The polyethylene bracket is made of polyethylene, and has a corresponding array of threaded holes on one side for installing the neutron source cladding. While fixing the neutron source, it shields the other side of the neutron radiation field that is not used, making the radiation field safer.

5. The uniform neutron radiation test device based on a neutron source array according to claim 1 is characterized in that: The calibration platform comprises a table, a guide rail assembly, and a translation drive motor, and the platform is guided and moved by the linear guide rail assembly.

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