An extended radionuclide neutron source neutron reference radiation device

Abstract

The present invention discloses an extended radionuclide neutron source neutron reference radiation device, comprising a neutron radiation field, a radionuclide neutron source, a migration mechanism and a neutron reference radiation device; the interior of the neutron radiation field is divided from top to bottom into a standard neutron reference radiation field and a simulated neutron reference radiation field by a partition, the neutron reference radiation device is placed in the simulated neutron reference radiation field, and the radionuclide neutron source migrates between the standard neutron reference radiation field, the simulated neutron reference radiation field and the neutron reference radiation device through the migration mechanism. The present invention optimizes the structure of the existing standard neutron reference radiation field storage device based on the radionuclide neutron source, constructs a neutron reference radiation field that is consistent with or close to the on-site neutron energy spectrum conditions, improves the calibration pertinence of the neutron dosimeter, and effectively improves the measurement accuracy of the on-site neutron radiation protection amount.

Description

Technical Field

[0001] The invention relates to the technical field of neutron physics, and in particular to an extended radionuclide neutron source neutron reference radiation device. Background Art

[0002] With the development and application of nuclear energy technology, neutrons are increasingly used in many fields such as physics, chemistry, medicine, engineering, oil exploration, nuclear industry, and industrial production. The radiation safety and protection issues brought about by this are becoming more and more important. Neutrons have a strong penetrating rate and are more harmful to the human body than the same dose of X-rays, gamma rays, etc. Accurate measurement of neutron radiation dose is crucial. The neutron radiation level for regional monitoring is usually measured by a neutron ambient dose equivalent meter (neutron dosimeter). Before measurement, the neutron dosimeter must be routinely verified, calibrated and tested to ensure the accuracy of the measurement results. The detection is usually carried out in a neutron reference radiation field. The neutron reference radiation device based on a radionuclide neutron source is one of the neutron reference radiation devices recommended by the national standard GB / T 14055.1 (ISO 8529-1).

[0003] The existing radionuclide neutron source neutron reference radiation device is mainly based on the radionuclide neutron source ( 241 Am-Be, 241 Am-B, 252 Cf and 252 Cf(D2O moderation)) is produced. Since the neutron dosimeter does not have a response function that is consistent with the change of the neutron injection-dose equivalent conversion coefficient h*(10) within the nominal energy range, when the neutron energy spectrum of the neutron reference radiation field is different from the neutron energy spectrum at the actual site, the calibration result cannot effectively correct the on-site measurement data, resulting in generally low accuracy of on-site neutron protection dose measurement. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an extended radionuclide neutron source neutron reference radiation device, which can effectively improve the measurement accuracy of on-site neutron radiation protection.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] An extended radionuclide neutron source neutron reference radiation device comprises a neutron radiation field, a radionuclide neutron source, a migration mechanism and a neutron reference radiation device, which can effectively improve the measurement accuracy of on-site neutron radiation protection. Specifically, the interior of the neutron radiation field is divided from top to bottom into a standard neutron reference radiation field and a simulated neutron reference radiation field by a partition, the neutron reference radiation device is placed in the simulated neutron reference radiation field, and the radionuclide neutron source migrates between the standard neutron reference radiation field and the neutron reference radiation device through the migration mechanism. The above-mentioned neutron reference radiation device comprises a shielding layer, and a moderator, a heavy metal block and a reflector block arranged in sequence, the moderator, the heavy metal block and the reflector block form a surface after arrangement, the shielding layer covers the surface, a channel is opened on the heavy metal block, and the shielding layer has an avoidance opening at the position corresponding to the channel port.

[0007] During routine calibration, the radionuclide neutron source is located in the standard neutron reference radiation field; during special calibration, the radionuclide neutron source is located in the neutron reference radiation device, and a simulated neutron reference radiation field is formed in the simulated neutron reference radiation field through the moderator; during neutron source storage, the radionuclide neutron source is located in the neutron reference radiation device, and the moderator is used to reduce the neutron / gamma dose rate outside the neutron reference radiation device to the radiation management level.

[0008] Preferably, the migration mechanism is a pulley migration mechanism, which includes pulleys respectively arranged in the standard neutron reference radiation field and the simulated neutron reference radiation field, and a migration ring simultaneously sleeved on the plurality of pulleys, wherein one of the pulleys is connected to the driving device as a driving wheel;

[0009] The radioactive nuclide neutron source is placed on the migration circle, a through hole is opened on the partition for the migration circle and the radioactive nuclide neutron source to pass through, and the neutron reference radiation device includes a channel for the radioactive nuclide neutron source to enter and for the migration circle to pass through.

[0010] Preferably, the migration ring is made of steel wire rope to ensure service life.

[0011] Preferably, the moderator is composed of multiple moderator layers, and the thickness and material of each moderator layer are set according to the neutron energy spectrum to be simulated. The moderator layer can simulate the neutron energy spectrum in different application scenarios by combining different moderator materials and different moderator thicknesses.

[0012] Preferably, the pulley migration mechanism has four groups of pulleys, and the four groups of pulleys are evenly arranged along the four corners of the rectangle in the standard neutron reference radiation field and the simulated neutron reference radiation field, and in the horizontal direction, the distance between two adjacent pulleys is greater than or equal to the maximum length of the neutron reference radiation device in the horizontal direction, so as to avoid mutual influence between the neutron reference radiation device and the migration circle.

[0013] Preferably, an assembly groove for assembling a pulley is provided at the bottom of the simulated neutron reference radiation field, a support plate connected to the edge of the simulated neutron reference radiation field is provided at the top of the assembly groove, and a notch is provided on the support plate for the migration ring to pass through.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention optimizes the structure of the existing standard neutron reference radiation field storage device based on a radioactive nuclide neutron source, constructs a neutron reference radiation field that is consistent with or close to the on-site neutron energy spectrum conditions, improves the calibration pertinence of the neutron dosimeter, and effectively improves the measurement accuracy of the on-site neutron radiation protection amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 It is a schematic cross-sectional structural diagram of the assembly of the neutron reference radiation device of the present invention.

[0018] Figure symbols: 1. Neutron radiation field, 11. Standard neutron reference radiation field, 12. Simulated neutron reference radiation field, 13. Assembly groove, 14. Support plate, 15. Notch, 2. Radionuclide neutron source, 3. Migration mechanism, 31. Pulley, 32. Migration ring, 4. Neutron reference radiation device, 41. Channel, 42. Shielding layer, 43. Moderator, 44. Heavy metal block, 45. Reflection block, 5. Partition, 51. Through hole. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1

[0021] The present embodiment discloses an extended radionuclide neutron source neutron reference radiation device, which constructs a neutron reference radiation field that is consistent with or close to the on-site neutron energy spectrum conditions by optimizing the structure of an existing standard neutron reference radiation field storage device based on a radionuclide neutron source, thereby improving the calibration pertinence of a neutron dosimeter and effectively improving the measurement accuracy of on-site neutron radiation protection.

[0022] like Figure 1-2The above-mentioned extended radionuclide neutron source neutron reference radiation device shown includes a neutron radiation field 1, a radionuclide neutron source 2, a migration mechanism 3 and a neutron reference radiation device 4, wherein the interior of the neutron radiation field 1 is divided from top to bottom into a standard neutron reference radiation field 11 and a simulated neutron reference radiation field 12 by a partition 5, the neutron reference radiation device 3 is placed in the simulated neutron reference radiation field 12, and the radionuclide neutron source 2 migrates between the standard neutron reference radiation field 11 and the neutron reference radiation device 4 through the migration mechanism 3.

[0023] The above-mentioned neutron reference radiation device 4 includes a shielding layer 42, and a moderator 43, a heavy metal block 44 and a reflector block 45 arranged in sequence. The moderator 43, the heavy metal block 44 and the reflector block 45 form a surface after arrangement, and the shielding layer 42 covers the surface. The channel 41 is opened on the heavy metal block 44, and the shielding layer 45 has an escape opening at the position corresponding to the port of the channel 41, wherein the moderator 43 moderates neutrons by elastic scattering, the heavy metal block 44 moderates neutrons by inelastic scattering, the reflector block 45 improves the fluence rate at the measurement position by reflecting neutrons, and the shielding layer 41 shields neutrons and gamma radiation.

[0024] During implementation, the position of the radionuclide neutron source 2 is moved by the migration mechanism 3 according to the requirements of the use status. Specifically, during routine calibration, the migration mechanism 3 moves the radionuclide neutron source 2 to the standard neutron reference radiation field 11; during special calibration, the migration mechanism 3 moves the radionuclide neutron source 2 to the neutron reference radiation device 4, and forms a simulated neutron reference radiation field in the simulated neutron reference radiation field 12 through the moderator 43; during neutron source storage, the migration mechanism 3 moves the radionuclide neutron source 2 to the channel 41 of the neutron reference radiation device 4, and uses the moderator 43, the heavy metal block 44 and the shielding layer 41 to reduce the neutron / γ dose rate outside the neutron reference radiation device to the radiation management level.

[0025] In some embodiments, the migration mechanism 3 is a linear module. Specifically, the linear module penetrates the partition 5 and the channel 41 of the neutron reference radiation device 4 at the same time, and is fixed at the bottom of the simulated neutron reference radiation field 12. The radioactive nuclide neutron source 2 is placed on the moving part of the linear module. The partition 5 has an avoidance channel for the radioactive nuclide neutron source 2 to pass through. The migration of the radioactive nuclide neutron source 2 in the standard neutron reference radiation field 11 and the channel 41 is achieved through the linear module. As a prior art, the linear module will not be described in detail here.

[0026] As a preferred solution of the above embodiment, the migration mechanism 3 is a pulley migration mechanism, which includes pulleys 31 respectively arranged in the standard neutron reference radiation field 11 and the simulated neutron reference radiation field 12, and migration rings 32 simultaneously sleeved on the plurality of pulleys 31, wherein one of the pulleys 31 is connected to the driving device as a driving wheel, wherein the radioactive nuclide neutron source 2 is placed on the migration ring 32, and the partition plate 5 is provided with a through hole 51 for the migration ring 32 and the radioactive nuclide neutron source 2 to pass through, and the neutron reference radiation device 4 includes a through hole 51 for the radioactive nuclide neutron source 2 to enter, And a channel 41 for the migration circle 32 to pass through, an assembly groove 13 for assembling the pulley 31 is provided at the bottom of the simulated neutron reference radiation field 12, a support plate 14 connected to the edge of the simulated neutron reference radiation field 12 is provided on the top of the assembly groove 13, and a notch 15 for the migration circle 32 to pass through is provided on the support plate 14. During implementation, when the driving wheel rotates, the migration circle 32 moves accordingly, and then the radioactive nuclide neutron source 2 arranged on the migration circle 32 also moves accordingly, thereby realizing the migration of the radioactive nuclide neutron source 2 in the standard neutron reference radiation field 11 and the channel 41.

[0027] The migration ring 32 is made of steel wire rope, which has high strength and ensures long service life.

[0028] The above-mentioned moderator 42 is composed of multiple layers of moderator layers. The thickness and material of each moderator layer are set according to the neutron energy spectrum to be simulated. By combining different moderator materials and different moderator thicknesses, the neutron energy spectrum in different application scenarios can be simulated, and then different neutron reference radiation fields can be simulated to improve the calibration pertinence of the neutron dosimeter. Specifically, given that the neutron radiation effect is closely related to its energy distribution, the neutron energy spectrum research is of indispensable importance in radiation protection dosimetry. The neutron energy distribution in different workplaces varies greatly, and the neutron injection-dose equivalent conversion coefficient strongly depends on the neutron energy. In addition, the response characteristics of various neutron dosimeters are different, and there are defects to varying degrees. Therefore, by establishing an extended radiation field that can simulate the neutron energy spectrum in different application scenarios, compared with the reference radiation field calibration of the radionuclide neutron source based on the existing ISO standard, the neutron dosimeter can more accurately simulate the neutron radiation level under actual application conditions during the calibration process, thereby improving the accuracy of the measurement.

[0029] The number of pulleys 31 in the above-mentioned pulley migration mechanism is four groups, and the four groups of pulleys 31 are evenly arranged along the four corners of the rectangle in the standard neutron reference radiation field 11 and the simulated neutron reference radiation field 12, and in the horizontal direction, the distance between two adjacent pulleys 31 is greater than or equal to the maximum length of the neutron reference radiation device 4 in the horizontal direction, so as to avoid friction between the migration ring 32 and the neutron reference radiation device 4 during the movement.

[0030] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. An extended radionuclide neutron source neutron reference radiation device, characterized in that: It comprises a neutron radiation field (1), a radionuclide neutron source (2), a migration mechanism (3) and a neutron reference radiation device (4); The interior of the neutron radiation field (1) is divided from top to bottom into a standard neutron reference radiation field (11) and a simulated neutron reference radiation field (12) by a partition (5); the neutron reference radiation device (3) is placed in the simulated neutron reference radiation field (12); and the radioactive nuclide neutron source (2) is migrated between the standard neutron reference radiation field (11), the simulated neutron reference radiation field (12) and the neutron reference radiation device (4) via a migration mechanism (3); The migration mechanism (3) is a pulley migration mechanism, comprising pulleys (31) respectively arranged in the standard neutron reference radiation field (11) and the simulated neutron reference radiation field (12), and a migration ring (32) simultaneously mounted on a plurality of the pulleys (31), wherein one of the pulleys (31) is connected to a driving device as a driving wheel; The radioactive nuclide neutron source (2) is placed on the migration circle (32), the partition (5) is provided with a through hole (51) for the migration circle (32) and the radioactive nuclide neutron source (2) to pass through, and the neutron reference radiation device (4) comprises a channel (41) for the radioactive nuclide neutron source (2) to enter and for the migration circle (32) to pass through.

2. The extended radionuclide neutron source neutron reference radiation device according to claim 1, characterized in that: The migration ring (32) is made of steel wire rope.

3. The extended radionuclide neutron source neutron reference radiation device according to claim 2, characterized in that: The neutron reference radiation device (4) comprises a shielding layer (42), and a moderator (43), a heavy metal block (44), and a reflector block (45) arranged in sequence, wherein the moderator (43), the heavy metal block (44), and the reflector block (45) form a surface after being arranged, the shielding layer (42) covers the surface, the channel (41) is opened on the heavy metal block (44), and the shielding layer (45) has an escape opening at a position corresponding to a port of the channel (41).

4. The extended radionuclide neutron source neutron reference radiation device according to claim 3, characterized in that: The moderator (42) is composed of multiple moderator layers, and the thickness and material of each moderator layer are set according to the neutron energy spectrum to be simulated.

5. The extended radionuclide neutron source neutron reference radiation device according to claim 4, characterized in that: The pulley migration mechanism has four groups of pulleys (31), and the four groups of pulleys (31) are evenly arranged along the four corners of a rectangle in the standard neutron reference radiation field (11) and the simulated neutron reference radiation field (12), and in the horizontal direction, the spacing between two adjacent pulleys (31) is greater than or equal to the maximum length of the neutron reference radiation device (4) in the horizontal direction.

6. The extended radionuclide neutron source neutron reference radiation device according to any one of claims 1 to 5, characterized in that: The bottom of the simulated neutron reference radiation field (12) is provided with an assembly groove (13) for assembling the pulley (31), the top of the assembly groove (13) is provided with a support plate (14) connected to the edge of the simulated neutron reference radiation field (12), and the support plate (14) is provided with a notch (15) for the migration ring (32) to pass through.

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