A uniform neutron irradiation test device based on a neutron source array

Abstract

The application relates to the technical field of nuclear radiation protection, and provides a uniform neutron radiation test device based on a neutron source array, which comprises a shielding water body, a polyethylene support, a neutron source array, a driving mechanism, a calibration platform and the like; the shielding water body is used for shielding the neutron radiation when the device is not used, so as to guarantee the safety of the operators; the polyethylene support is used for mounting the neutron source; the driving mechanism drives the polyethylene support to move; under the driving of the polyethylene support, the neutron source array is either immersed into the water body to be shielded or floated out of the water surface to obtain a uniform neutron radiation field; the calibration platform is used for placing and fixing the instrument to be measured, and the parking position of the calibration platform can be selected according to the side scale. The test device can generate a relatively uniform neutron field with a large size, and the distance between the neutron radiation detection instrument and the neutron source can be adjusted; when the detection instrument is tested, the accuracy is high, and the test result is reliable.

Description

TECHNICAL FIELD

[0001] The present application 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

[0002] Neutron radiation is one of the important ionizing radiation types, and the types of neutron radiation detection instruments are also various. At present, the testing and calibration of neutron radiation detection instruments are mostly carried out in the radiation field generated by a single approximate point source standard neutron source. For instruments with large size, the field at the irradiated position is not uniform due to the large spatial span of the instrument, thereby causing large errors in the process of equipment testing, calibration, etc., and seriously affecting the accuracy of instrument monitoring data. A few radiation fields established by multiple neutron sources can only scale the intensity of individual standard radiation fields due to method limitations, which is prone to large systematic errors and is not conducive to accurate scaling of instruments. SUMMARY

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

[0004] The technical solution adopted by the present application to solve its technical problems 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 the neutron radiation when the device is not in use to ensure the safety of the operators. The shielding water body mainly comprises a cement base, a cement cover plate with lead plates, and water filled in the interior of the base.

[0007] The polyethylene support is used to install the neutron source and drive the neutron source array up and down by the driving mechanism.

[0008] The neutron source array is composed of a neutron source and a neutron source cladding. The neutron source is packaged in the neutron source cladding, and the neutron source cladding is installed on the polyethylene support by screw connection, so that the neutron source protrudes from the support and is less affected in the radiation field direction, making it easier to form a uniform radiation field.

[0009] The driving mechanism comprises a motor, a screw rod, and a support structure. The motor controls the rotation of the screw rod through a controller to drive the polyethylene support to move. Under the driving of the polyethylene support, the neutron source array is either shielded by being immersed in the water body or obtains a uniform neutron radiation field by floating out of the water surface.

[0010] The calibration platform is arranged above the shielding water body at a position in front of the neutron source array, a fixing device is arranged above the calibration platform for placing and fixing the instrument to be measured, and the calibration platform is provided with rollers and guide rails below, so that the parking position of the calibration platform can be selected according to the side scale.

[0011] In the technical scheme, the neutron source is selected as an am-be source 241 The am-be source has a long half-life, can be used for a long time, and is convenient to maintain. The number of neutron sources is determined by the size of the required neutron radiation field through Monte Carlo simulation calculation. In order to facilitate the inversion of the neutron source, the neutron source is first installed in the shell, and then directly installed on the polyethylene support, which can greatly reduce the influence on personnel during the inversion process.

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

[0013] In the technical scheme, the polyethylene support is made of polyethylene, and a threaded hole corresponding to the array is formed on one side to install the neutron source cladding. While fixing the neutron source, the other side not used in the neutron radiation field direction constitutes a shield, making the radiation field safer.

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

[0015] The present application is based on a uniform neutron radiation test device of a neutron source array. Compared with the prior art, the present application has the advantages of being able to generate a larger and more uniform neutron radiation field, high accuracy when testing the detection instrument, and reliable test results. In addition, since the main shielding body is a water body, the construction difficulty and cost can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 The present application is based on a uniform neutron radiation test device of a neutron source array. Compared with the prior art, the present application has the advantages of being able to generate a larger and more uniform neutron radiation field, high accuracy when testing the detection instrument, and reliable test results. In addition, since the main shielding body is a water body, the construction difficulty and cost can be reduced.

[0017] Fig. 2 The present application is based on a uniform neutron radiation test device of a neutron source array. Compared with the prior art, the present application has the advantages of being able to generate a larger and more uniform neutron radiation field, high accuracy when testing the detection instrument, and reliable test results. In addition, since the main shielding body is a water body, the construction difficulty and cost can be reduced.

[0018] Fig. 3 The present application is based on a uniform neutron radiation test device of a neutron source array. Compared with the prior art, the present application has the advantages of being able to generate a larger and more uniform neutron radiation field, high accuracy when testing the detection instrument, and reliable test results. In addition, since the main shielding body is a water body, the construction difficulty and cost can be reduced.

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

[0020] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the concept of the present application, so the present application is not limited to the specific implementations disclosed below.

[0021] As shown in the embodiment, a uniform neutron irradiation test device based on a neutron source array is provided, which comprises a shielding water body 4, a polyethylene support 3, a neutron source array 7, a driving mechanism, a calibration platform 6 and the like. Figs. 1-2 The shielding water body 4 mainly comprises a cement base, a cement cover plate with lead plate 5 and water filled in the inside of the base. The shielding water body 4 uses a water body with good neutron moderation and shielding effect as shielding. In order to shield the γ rays generated in the neutron moderation process, a certain thickness of cement base and cement cover plate with lead plate is added outside the water body. The thickness of various materials is determined according to the radiation intensity.

[0022] The polyethylene support 3 is used for installing the neutron source. The polyethylene support 3 is driven by the driving mechanism to drive the neutron source array up and down. The polyethylene support 3 is made of polyethylene. One side has screw holes corresponding to the array to install the neutron source cladding. While fixing the neutron source, the other side is shielded in the direction of the neutron radiation field, so that the radiation field is safer.

[0023] The neutron source array 7 is composed of neutron sources and neutron source cladding. The neutron sources are packaged in the neutron source cladding. The neutron source cladding is installed on the polyethylene support through threaded connection, so that the neutron sources protrude from the support and are less affected in the radiation field direction, and it is easier to form a uniform radiation field. Fourteen 241am-be neutron sources are used to form a two-row seven-column array distribution. The activity of the four neutron sources placed at both ends is 2 ci, and the activity of the ten neutron sources in the middle is 1 ci.

[0024] The driving mechanism comprises a driving motor 1, a lead screw 2 and a support structure. The motor controls the rotation of the lead screw through a controller to drive the polyethylene support to move. Under the driving of the polyethylene support, the neutron source array is either immersed in the water body to be shielded or floated out of the water surface to obtain a uniform neutron radiation field.

[0025] The calibration platform 6 is arranged above the shielding water body 4 and located in front of the neutron source array 7. A fixing device is arranged above the calibration platform 6 for placing and fixing the instrument to be measured. The calibration platform 6 has rollers and guide rails below, and the stopping position of the calibration platform can be selected according to the side scale 10.

[0026] Fig. 3 ​As shown, the calibration platform 6 includes a table top 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 the embodiment is as follows:

[0028] Before the test, the neutron source array is in a shielding position under water. The staff places the instrument to be measured on the calibration platform and fixes it with a fixing device, adjusts the calibration platform to the position required for calibration according to the scale, exits the laboratory, and drives the polyethylene support to bring the neutron source array out of water to the position of establishing a radiation field through remote control. Then the instrument to be measured is calibrated or calibrated in the standard neutron radiation field. After the test, the polyethylene support is driven into water to enter the shielding state through remote control, the instrument that has been measured is removed, and the calibration platform is returned to the original position.

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

[0030] The above is only one use example of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A uniform neutron irradiation testing apparatus based on an array of neutron sources, characterized by: The shielding water body, the polyethylene support, the neutron source array, the driving mechanism and the calibration platform are included. The shielding water body is used for shielding the neutron radiation when the device is not used to protect the safety of the operator, and the shielding water body includes a cement base, a cement cover plate with lead plate and water filled in the inside of the base. The polyethylene support is used for installing the neutron source, and the neutron source array is driven up and down by the driving mechanism. The polyethylene support is made of polyethylene, and one side is provided with threaded holes corresponding to the array to install the neutron source cladding. The neutron source array includes the neutron source and the neutron source cladding, and the neutron source is packaged in the neutron source cladding. The driving mechanism includes a motor, a screw rod and a support structure.

2. The uniform neutron irradiation testing apparatus based on an array of neutron sources of claim 1, wherein: The neutron source is chosen 241 am-be source, the number of neutron sources is determined by the size of the required neutron radiation field by Monte Carlo simulation calculation.

3. The uniform neutron irradiation testing apparatus based on a neutron source array of claim 1 or 2, characterized by: Fourteen 241 The am-be neutron source forms a 2-row 7-column array distribution, wherein the activities of the 4 neutron sources at both ends are both 2 Ci, and the activities of the 10 neutron sources in the middle are all 1 Ci.

4. The uniform neutron irradiation testing apparatus based on an array of neutron sources of claim 1, wherein: The calibration platform is arranged above the shielding water body and in front of the neutron source array. The calibration platform includes a table top, a guide rail assembly and a translation driving motor. The platform is guided and moved by the linear guide rail assembly.

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