Neutron personal dosimeter

Abstract

The application relates to the technical field of neutron personal dose, and provides a neutron personal dosimeter, which comprises a first detection module, a second detection module, a back-to-back detection module and a third detection module, the first detection module is used for measuring full-energy-region neutrons; the second detection module is used for measuring fast neutrons; the back-to-back detection module is used for discriminating spatial high-energy charged particles; and the third detection module is used for measuring full-energy-region neutrons, and the sensitivity of the third detection module to medium-energy neutrons is higher than that of the first detection module; a first slow-down wrapping part wraps at least part of the first detection module; a second slow-down wrapping part wraps at least part of the second detection module; a first absorption wrapping part wraps at least part of the back-to-back detection module; and a second absorption wrapping part wraps at least part of the third detection module, so that the neutron personal dosimeter is suitable for measuring the neutron personal dose equivalent in a cosmic space environment.

Description

Technical Field

[0001] This application relates to the field of neutron personal dosimetry technology, and more particularly to a neutron personal dosimeter. Background Technology

[0002] This section is intended to provide background or context for embodiments of this application. The description herein is not intended to imply that it is prior art simply because it is included in this section.

[0003] In the field of manned spaceflight, when satellites, manned spacecraft, and other spacecraft are operating in near-Earth orbit and interstellar space, the high-energy charged particles, photons, and neutrons react with the spacecraft's cabin materials to produce secondary charged particles and neutrons, thus forming a complex mixed radiation field. This poses a significant challenge to the measurement of personal dosimetry in space. In space, the energy of protons can reach as high as GeV (gigaelectron volts), and the energies of the resulting secondary neutrons can also reach the same order of magnitude. Ground-based neutron dosimeters typically cover a neutron energy measurement range of 2.53 × 10⁻⁶. -8 The MeV to 15 MeV range is insufficient for measuring and transferring the personal dose equivalent of spacecraft astronauts. Besides the limited energy measurement range, the response of neutron personal dosimeters to neutron personal dose equivalents also varies drastically with energy across such a wide energy range. Space neutrons originate from the interaction of high-energy charged particles with spacecraft materials or atmospheric matter; they are secondary particles, and their energy spectrum is not only closely related to the space charged particle source term but also changes with the target material and structure. Therefore, the space neutron source term is constantly changing depending on the type, location, and orbit of the spacecraft. In practical use, the uncertainty range of commonly used ground-based personal dosimeters can be far greater than 30% to 200%, demonstrating the significant impact of neutron field energy spectrum differences on personal dose equivalent measurement results. Summary of the Invention

[0004] In view of this, this application aims to provide a neutron personal dosimeter that can be used to measure neutron personal dose equivalent in a space environment.

[0005] This application provides a neutron personal dosimeter, comprising:

[0006] The first detection module is used to measure neutrons in the entire energy range;

[0007] The second detection module is located behind the first detection module, and the second detection module is used to measure fast neutrons;

[0008] An anti-coincidence detection module is disposed on the rear side of the second detection module, and the anti-coincidence detection module is used to identify high-energy charged particles in space;

[0009] The third detection module is located behind the anti-coincidence detection module. The third detection module is used to measure neutrons in the full energy range. The sensitivity of the third detection module to medium-energy neutrons is higher than that of the first detection module.

[0010] A first slowing-down package encloses at least a portion of the first detection module;

[0011] The second slowing-down package encloses at least a portion of the second detection module;

[0012] A first absorbent package encapsulates at least a portion of the anti-coincidence detection module;

[0013] The second absorbent package encloses at least a portion of the third detection module.

[0014] In some embodiments, the first detection module includes a first detector, a first moderator, and a first converter, wherein the first moderator, the first converter, and the first detector are stacked from front to back.

[0015] In some embodiments, the second detection module includes a second detector and a second moderator, the second moderator being disposed in front of the second detector.

[0016] In some embodiments, the third detection module includes a third detector, a third moderator, and a second converter, wherein the third moderator, the second converter, and the third detector are stacked from front to back.

[0017] In some embodiments, the anti-coincidence detection module includes an anti-coincidence detector, a fourth moderator, and a third converter, wherein the fourth moderator, the third converter, and the anti-coincidence detector are stacked from front to back.

[0018] In some embodiments, the anti-coincidence time window of the anti-coincidence detection module is 50 μs to 100 μs.

[0019] In some embodiments, the neutron personal dosimeter includes a housing having a mounting cavity in which the first detection module, the second detection module, the third detection module, and the anti-coincidence detection module are all disposed.

[0020] In some embodiments, the neutron personal dosimeter includes a preamplifier disposed within the housing, and the first detection module, the second detection module, the third detection module, and the anti-coincidence detection module are each electrically connected to one of the preamplifiers.

[0021] In some embodiments, the thickness of the outer casing is 1 mm to 3 mm.

[0022] In some embodiments, the housing is made of aluminum alloy.

[0023] The neutron personal dosimeter provided in this application has three detection modules: a first detection module, a second detection module, and a third detection module. These modules exhibit different responses to neutrons in different energy ranges. Specifically, the first detection module has the highest response to low-energy neutrons, the second detection module only responds to fast neutrons, and the third detection module has the highest response to medium-energy neutrons. The influence of high-energy charged particles in space is eliminated by using the anti-coincidence method of the anti-coincidence detection module. This is a function not available in ground-based general-purpose personal dosimeters. The neutron personal dosimeter of this application not only broadens the neutron energy measurement range but is also suitable for measuring neutron personal dose equivalent in the space environment, thus improving the measurement accuracy of the neutron personal dosimeter under mixed energy fields. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the neutron personal dosimeter in the embodiments of this application.

[0025] Explanation of reference numerals in the attached figures

[0026] 1. First detection module; 11. First detector; 12. First moderator; 13. First converter; 14. First support base; 2. Second detection module; 21. Second detector; 22. Second moderator; 23. Second support base; 3. Third detection module; 31. Third detector; 32. Third moderator; 33. Second converter; 34. Third support base; 4. Anti-coincidence detection module; 41. Anti-coincidence detector; 42. Fourth moderator; 43. Third converter; 44. Fourth support base; 5. First moderator wrapper; 6. Second moderator wrapper; 7. First absorbent wrapper; 8. Second absorbent wrapper; 9. Outer shell; 9a. Mounting cavity; 10. Preamplifier; 200. Phantom. Detailed Implementation

[0027] Where there is no conflict, the embodiments and technical features in the embodiments of this application can be combined with each other. The detailed description in the specific implementation should be understood as an explanation of the purpose of this application and should not be regarded as an undue limitation on this application.

[0028] It should be noted that, in the embodiments of this application, "rear" refers to the side of the neutron personal dosimeter closer to the phantom 200, such as the human body, in the usage state, while "front" is the opposite, referring to the side of the neutron personal dosimeter farther from the phantom 200, such as the human body, in the usage state. In the embodiments of this application, the orientation or positional relationship of "front" and "rear" is based on the orientation or positional relationship shown in the accompanying drawings. It should be understood that these orientational terms are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. "First," "second," "third," and "fourth," etc., are only used for distinction, and not for indicating order or importance. The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] In this embodiment, the unit "eV" represents electron volts. The unit "keV" represents kiloelectron volts. The unit "MeV" represents megaelectron volts. The unit "μs" represents microseconds.

[0030] Please see Figure 1 This application provides a neutron personal dosimeter for obtaining neutron personal dose equivalent, which can be used to evaluate the effects of neutrons on a phantom 200, such as a human body.

[0031] Please see Figure 1 The neutron personal dosimeter includes a first detection module 1, a second detection module 2, a third detection module 3, an anti-coincidence detection module 4, a first moderation encapsulation element 5, a second moderation encapsulation element 6, a first absorption encapsulation element 7, and a second absorption encapsulation element 8.

[0032] The neutron personal dosimeter provided in this application divides the neutron energy range into three regions: low-energy neutron, medium-energy neutron, and fast neutron. The low-energy neutron region ranges from 0.025 eV to 1 keV; the medium-energy neutron region ranges from 1 keV to 1 MeV; and the fast neutron region ranges from 1 MeV to 100 MeV. In other words, the neutron energy measurement range of the neutron personal dosimeter covers 0.025 eV to 100 MeV.

[0033] The first detection module 1 is used to measure neutrons in the full energy range. That is, the first detection module 1 can measure neutrons in three energy ranges: low-energy neutron, medium-energy neutron, and fast neutron.

[0034] The second detection module 2 is located behind the first detection module 1, and is used to measure fast neutrons. The second detection module 2 is located on the side of the first detection module 1 closest to the human body.

[0035] The anti-coincidence detection module 4 is located behind the second detection module 2 and is used to identify high-energy charged particles in space. The anti-coincidence detection module 4 is located on the side of the second detection module 2 closest to the human body.

[0036] High-energy charged particles in space include, but are not limited to, protons.

[0037] The third detection module 3 is located behind the anti-coincidence detection module 4. The third detection module 3 is used to measure neutrons in the full energy range, and its sensitivity to medium-energy neutrons is higher than that of the first detection module 1. The third detection module 3 is located on the side of the anti-coincidence detection module 4 closest to the human body.

[0038] The first slowing-down envelope 5 encloses at least a portion of the first detection module 1. The first slowing-down envelope 5 is used to slow down neutrons, for example, to slow down fast neutrons. The first slowing-down envelope 5 may enclose a portion of the first detection module 1, or it may enclose the entire first detection module 1.

[0039] The second slowing-down envelope 6 encloses at least a portion of the second detection module 2. The second slowing-down envelope 6 is used to slow down neutrons, for example, to slow down fast neutrons. The second slowing-down envelope 6 may enclose a portion of the second detection module 2, or it may enclose the entire second detection module 2.

[0040] The first absorbing envelope 7 encloses at least a portion of the anti-coincidence detection module 4. The first absorbing envelope 7 is used to absorb neutrons. For example, the first absorbing envelope 7 encloses a portion of the anti-coincidence detection module 4, or the first absorbing envelope 7 encloses the entire anti-coincidence detection module 4.

[0041] The second absorbing envelope 8 encloses at least a portion of the third detection module 3. The second absorbing envelope 8 is used to absorb neutrons. For example, the second absorbing envelope 8 encloses a portion of the third detection module 3, or the second absorbing envelope 8 encloses the entire third detection module 3.

[0042] Because the third detection module 3 is enclosed by the second absorber and is closer to the phantom 200 (e.g., a human body), the sensitivity of the third detection module 3 to medium-energy neutrons is higher than that of the first detection module 1. In other words, the sensitivity of the third detection module 3 to low-energy neutrons is lower than that of the first detection module 1. The response of the third detection module 3 to medium-energy neutrons is higher than that of the first detection module 1, and the response of the third detection module 3 to low-energy neutrons is lower than that of the first detection module 1.

[0043] The neutron personal dosimeter provided in this application has different responses to neutrons in different energy ranges in its first detection module 1, second detection module 2, and third detection module 3. Specifically, the first detection module 1 has the highest response to low-energy neutrons, the second detection module 2 only responds to fast neutrons, and the third detection module 3 has the highest response to medium-energy neutrons. The influence of high-energy charged particles in space is eliminated by the anti-coincidence method of the anti-coincidence detection module 4, which is a function not available in ground-based general-purpose personal dosimeters. The neutron personal dosimeter of this application can not only broaden the neutron energy measurement range, but also be applicable to the measurement of neutron personal dose equivalent in the space environment, and improve the measurement accuracy of the neutron personal dosimeter under different energy spectrum mixing fields.

[0044] In one embodiment, please refer to Figure 1 The first detection module 1 includes a first detector 11, a first moderator 12, and a first converter 13, which are stacked from front to back. That is, the first moderator 12 is located in front of the first detector 11, and the first converter 13 is located between the first moderator 12 and the first detector 11.

[0045] For example, the first converter 13 and the first detector 11 are spaced apart. That is, the first converter 13 and the first detector 11 have a gap.

[0046] The first moderator 12 is used to slow down neutrons and generate secondary particles; for example, the first moderator 12 slows down fast neutrons. The first converter 13 is used to interact with neutrons to generate secondary particles. The first detector 11 is used to record secondary particles and generate electrical signals.

[0047] In this embodiment, the incident neutrons injected into the neutron personal dosimeter pass sequentially through a first moderator 12, a first converter 13, and a first detector 11. The first moderator 12 decelerates the incident neutrons and generates secondary particles. The first converter 13 interacts with the neutrons to generate secondary particles. The secondary particles are injected into the first detector 11 to generate detectable electrical signals, thereby realizing neutron measurement.

[0048] In some embodiments, the first detection module 1 can be used to measure the recoil protons produced by fast neutrons, and can also measure alpha particles and tritium produced by medium-energy neutrons and low-energy neutrons.

[0049] For example, fast neutrons can elastically scatter with the hydrogen nuclei of the first moderator 12 to generate recoil protons. These recoil protons have a certain electric charge and can be recorded as secondary particles. The first detector 11 can record these recoil protons.

[0050] For example, medium-energy neutrons and low-energy neutrons can react with the first converter 13 to produce alpha particles and tritium. Alpha particles and tritium have a certain electric charge and can be recorded as secondary particles. The first detector 11 can record alpha particles and tritium.

[0051] In this embodiment, the first detection module 1 can detect neutrons by recording the recoil protons, alpha particles and tritium generated by the incident neutrons.

[0052] In one embodiment, please refer to Figure 1 The second detection module 2 includes a second detector 21 and a second moderator 22, with the second moderator 22 disposed in front of the second detector 21.

[0053] For example, the second moderator 22 and the second detector 21 are spaced apart. That is, the second moderator 22 and the second detector 21 have a gap.

[0054] The second moderator 22 is used to slow down neutrons and generate secondary particles; for example, the second moderator 22 slows down fast neutrons. The second detector 21 is used to record secondary particles and generate electrical signals.

[0055] In this embodiment, the incident neutrons injected into the neutron personal dosimeter pass sequentially through the second moderator 22 and the second detector 21. The second moderator 22 decelerates the incident neutrons and generates secondary particles. The secondary particles enter the second detector 21 and generate a detectable electrical signal.

[0056] In some embodiments, the second detection module 2 can be used to measure the recoil protons produced by fast neutrons.

[0057] For example, fast neutrons can undergo elastic scattering with the hydrogen nuclei of the second moderator 22 to generate recoil protons. These recoil protons have a certain charge and can be recorded as secondary particles. The second detector 21 can record these recoil protons.

[0058] In this embodiment, the second detection module 2 can detect neutrons by recording the recoil protons generated by the incident neutrons.

[0059] In one embodiment, please refer to Figure 1 The third detection module 3 includes a third detector 31, a third moderator 32, and a second converter 33, which are stacked from front to back. That is, the third moderator 32 is located in front of the third detector 31, and the second converter 33 is located between the third moderator 32 and the third detector 31.

[0060] For example, the second converter 33 and the third detector 31 are spaced apart. That is, the second converter 33 and the third detector 31 have a gap.

[0061] The third moderator 32 is used to slow down neutrons and generate secondary particles; for example, the third moderator 32 slows down fast neutrons. The second converter 33 is used to interact with neutrons to generate secondary particles. The third detector 31 is used to record secondary particles and generate electrical signals.

[0062] In this embodiment, the incident neutrons injected into the neutron personal dosimeter pass sequentially through a third moderator 32, a second converter 33, and a third detector 31. The third moderator 32 decelerates the incident neutrons and generates secondary particles. The second converter 33 interacts with the neutrons to generate secondary particles. The secondary particles enter the third detector 31 to generate a detectable electrical signal.

[0063] In some embodiments, the third detection module 3 can be used to measure the recoil protons produced by fast neutrons, and can also measure alpha particles and tritium produced by medium-energy neutrons and low-energy neutrons.

[0064] For example, fast neutrons can elastically scatter with the hydrogen nuclei of the third moderator 32 to generate recoil protons. These recoil protons have a certain charge and can be recorded as secondary particles. The third detector 31 can record these recoil protons.

[0065] For example, medium-energy neutrons and low-energy neutrons can react with the second converter 33 to produce alpha particles and tritium. Alpha particles and tritium have a certain electric charge and can be recorded as secondary particles. The third detector 31 can record alpha particles and tritium.

[0066] In this embodiment, the third detection module 3 can detect neutrons by recording the recoil protons, alpha particles and tritium generated by the incident neutrons.

[0067] In some embodiments, please refer to Figure 1 The anti-coincidence detection module 4 includes an anti-coincidence detector 41, a fourth moderator 42, and a third converter 43, which are stacked from front to back. That is, the fourth moderator 42 is located in front of the anti-coincidence detector 41, and the third converter 43 is located between the fourth moderator 42 and the anti-coincidence detector 41.

[0068] For example, the third converter 43 and the anti-coincidence detector 41 are spaced apart. That is, the third converter 43 and the anti-coincidence detector 41 have a gap.

[0069] The fourth moderator 42 is used to slow down neutrons and generate secondary particles; for example, the third moderator 32 slows down fast neutrons. The third converter 43 is used to interact with neutrons to generate secondary particles. High-energy charged particles in space can pass through the first detection module 1 and the second detection module 2 and enter the anti-coincidence detector 41. The anti-coincidence detector 41 is used to record secondary particles and high-energy charged particles in space and generate electrical signals.

[0070] In this embodiment, incident neutrons and high-energy charged particles in space enter the neutron personal dosimeter sequentially through a fourth moderator 42, a third converter 43, and an anti-coincidence detector 41. The fourth moderator 42 decelerates the incident neutrons and generates secondary particles. The third converter 43 interacts with the neutrons to generate secondary particles. The secondary particles and high-energy charged particles in space enter the anti-coincidence detector 41 to generate a detectable electrical signal.

[0071] In some embodiments, the first detector 11 is a semiconductor detector. Using a semiconductor detector enables active measurement and improves measurement accuracy.

[0072] In some embodiments, the second detector 21 is a semiconductor detector. Using a semiconductor detector enables active measurement and improves measurement accuracy.

[0073] In some embodiments, the third detector 31 is a semiconductor detector. Using a semiconductor detector enables active measurement and improves measurement accuracy.

[0074] In some embodiments, the anti-coincidence detector 41 is a semiconductor detector. Using a semiconductor detector enables active measurement and improves measurement accuracy.

[0075] Semiconductor detectors use semiconductor materials including, but not limited to, silicon. In other words, semiconductor detectors include, but are not limited to, planar silicon detectors.

[0076] Planar silicon detectors include, but are not limited to, passivated implanted planar silicon detectors (PIPS detectors), such as ion-implanted planar silicon detectors. Planar silicon detectors are characterized by their small size, light weight, and high sensitivity.

[0077] Planar silicon detectors can be manufactured using planar processes based on photolithography.

[0078] An ion-implanted planar silicon detector is a detector formed by implanting ions into the interior of a silicon wafer. By adjusting the intensity and energy of the ion beam, the depth and concentration of doped ions in the silicon wafer can be controlled, and the shape of the doped ions can also be controlled.

[0079] The first detector 11, the second detector 21, the third detector 31 and the anti-coincidence detector 41 can all be known passivated injection type silicon detectors.

[0080] In some embodiments, the sensitive region diameter of the passivated-injection planar silicon detector is 10 mm, and the maximum depletion layer thickness is 300 μm. During use with a neutron personal dosimeter, the high voltage of the passivated-injection planar silicon detector can be set to 3.5 V, at which point the sensitive region thickness is approximately 100 μm. At this sensitive region thickness, the passivated-injection planar silicon detector can completely deposit incident neutrons and...6 For alpha and tritium particles generated by the Li reaction, the passivated injection-type planar silicon detector is a full-deposition detector. However, recoil protons have a long range and a wide energy range in silicon. When the recoil proton energy is high, the passivated injection-type planar silicon detector becomes a penetration detector, and the particle energy can only be determined by the difference in the shape of the energy deposition spectrum produced by recoil protons of different energies. The first detection module 1 has the highest response to low-energy neutrons, such as thermal neutrons. That is to say, the low-energy neutron sensitivity of the third detection module 3 is lower than that of the first detection module 1. The third detection module 3 has the highest response to medium-energy neutrons. The second detection module 2 only responds to fast neutrons.

[0081] In one embodiment, the first slowing package 5 and the second slowing package 6 are made of the same material. For example, both the first slowing package 5 and the second slowing package 6 are made of polyethylene.

[0082] In one embodiment, the first slowing package 5 and the second slowing package 6 have the same structural shape.

[0083] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the projections of the first slowing-down package 5 and the second slowing-down package 6 coincide. That is, the shapes and areas of the projections of the first slowing-down package 5 and the second slowing-down package 6 are the same.

[0084] In one embodiment, the first slowing package 5 has a rearward-opening first receiving groove, in which the first detection module 1 is housed.

[0085] In one embodiment, the second slowing package 6 has a rearward-opening second receiving groove, in which the second detection module 2 is housed.

[0086] In one embodiment, the first slowing-down package 5 includes a first intermediate portion and a first surrounding portion, the first surrounding portion surrounding the outer periphery of the first intermediate portion, and the first intermediate portion forming a first receiving groove. The second slowing-down package 6 includes a second intermediate portion and a second surrounding portion, the second surrounding portion surrounding the outer periphery of the second intermediate portion, and the second intermediate portion forming a second receiving groove. The thickness of the first intermediate portion is the same as the thickness of the second intermediate portion, and the thickness of the first surrounding portion is the same as the thickness of the second surrounding portion. Using a plane perpendicular to the front-back direction as the projection plane, the projection of the first intermediate portion coincides with the projection of the second intermediate portion, and the projection of the first surrounding portion coincides with the projection of the second surrounding portion.

[0087] In one embodiment, the first absorbent package 7 and the second absorbent package 8 are made of the same material. Exemplarily, both the first absorbent package 7 and the second absorbent package 8 are made of boron-containing polyethylene, for example, boron-containing polyethylene includes B4C. The thickness of the boron-containing polyethylene can be 2 mm.

[0088] In one embodiment, the first absorbent package 7 and the second absorbent package 8 have the same structural shape.

[0089] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the projections of the first absorbent package 7 and the second absorbent package 8 coincide. That is, the shapes and areas of the projections of the first absorbent package 7 and the second absorbent package 8 are the same.

[0090] In one embodiment, a plane perpendicular to the front-back direction is used as the projection plane, and the projected shape of the boron-containing polyethylene is approximately circular. For example, the diameter of the projected shape of the boron-containing polyethylene is 20 mm.

[0091] In one embodiment, the first absorbent package 7 has a rearward-opening first placement groove, and the anti-contrast detection module 4 is accommodated in the first placement groove.

[0092] In one embodiment, the second absorbent package 8 has a rearward-opening second placement groove, and the third detection module 3 is housed in the second placement groove.

[0093] In one embodiment, the first absorbent package 7 includes a first central portion and a first circumferential portion, the first circumferential portion surrounding the outer periphery of the first central portion, and the first central portion forming a first placement groove. The second absorbent package 8 includes a second central portion and a second circumferential portion, the second circumferential portion surrounding the outer periphery of the second central portion, and the second central portion forming a second placement groove. The thickness of the first central portion is the same as the thickness of the second central portion, and the thickness of the first circumferential portion is the same as the thickness of the second circumferential portion. Using a plane perpendicular to the front-back direction as the projection plane, the projection of the first central portion coincides with the projection of the second central portion, and the projection of the first circumferential portion coincides with the projection of the second circumferential portion.

[0094] In one embodiment, the first moderator 12, the second moderator 22, the third moderator 32, and the fourth moderator 42 are all made of the same material. For example, the first moderator 12, the second moderator 22, the third moderator 32, and the fourth moderator 42 are all made of polyethylene.

[0095] In one embodiment, the first moderator 12, the second moderator 22, the third moderator 32, and the fourth moderator 42 all have the same dimensions in the front-to-back direction.

[0096] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the projections of the first moderating body 12, the second moderating body 22, the third moderating body 32, and the fourth moderating body 42 all overlap. That is, the projection shapes and areas of the first moderating body 12, the second moderating body 22, the third moderating body 32, and the fourth moderating body 42 are all the same.

[0097] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the projection shapes of the first slowing body 12, the second slowing body 22, the third slowing body 32 and the fourth slowing body 42 can all be circular.

[0098] In one embodiment, the dimensions of the first moderator 12, the second moderator 22, the third moderator 32, and the fourth moderator 42 in the front-to-back direction are all 2 mm.

[0099] In one embodiment, the first converter 13, the second converter 33, and the third converter 43 are all made of the same material. For example, the first converter 13, the second converter 33, and the third converter 43 are all made of the same material. 6 LiF (lithium fluoride).

[0100] In one embodiment, the first converter 13, the second converter 33, and the third converter 43 have the same dimensions in the front-to-back direction.

[0101] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the projections of the first transforming body 13, the second transforming body 33, and the third transforming body 43 all overlap. That is, the projection shapes and areas of the first transforming body 13, the second transforming body 33, and the third transforming body 43 are all the same.

[0102] In one embodiment, the first converter 13 may be attached to the rear side of the first moderator 12. The attachment method includes, but is not limited to, coating.

[0103] In one embodiment, the second converter 33 may be attached to the rear side of the third moderator 32. The attachment method includes, but is not limited to, coating.

[0104] In one embodiment, the third converter 43 may be attached to the rear side of the fourth moderator 42. The attachment method includes, but is not limited to, coating.

[0105] The dimensions of the first converter 13, the second converter 33, and the third converter 43 along the front-to-back direction can be set according to requirements, for example, according to the range of alpha particles and tritium in the first converter 13, the second converter 33, and the third converter 43.

[0106] In one embodiment, the dimensions of the first converter 13, the second converter 33, and the third converter 43 along the front-to-back direction can all be 4 μm (micrometers), and their mass thickness can be 1 mg / cm. 2 .

[0107] In one embodiment, please refer to Figure 1The neutron personal dosimeter includes a housing 9, which has a mounting cavity 9a. A first detection module 1, a second detection module 2, a third detection module 3, and an anti-coincidence detection module 4 are all housed within the mounting cavity 9a. The housing 9 serves to protect the first detection module 1, the second detection module 2, the third detection module 3, and the anti-coincidence detection module 4, and also facilitates the user's grip on the housing 9 for easy use of the neutron personal dosimeter.

[0108] In one embodiment, please refer to Figure 1 The neutron personal dosimeter includes a preamplifier 10 housed within a casing 9. A first detection module 1, a second detection module 2, a third detection module 3, and an anti-coincidence detection module 4 are each electrically connected to a preamplifier 10. In other words, the four preamplifiers 10 are connected one-to-one with the first detection module 1, the second detection module 2, the third detection module 3, and the anti-coincidence detection module 4, respectively.

[0109] In this embodiment, the preamplifier 10 is used to amplify the electrical signals generated by each detection module and improve the signal-to-noise ratio.

[0110] In one embodiment, the thickness of the outer casing 9 is 1 mm to 3 mm. For example, the thickness of the outer casing 9 is 1 mm, 1.5 mm, 2 mm, or 3 mm, etc. In this way, the outer casing 9 can meet the requirements of structural strength and transmission of incident neutrons.

[0111] In one embodiment, the outer shell 9 is made of aluminum alloy. Aluminum alloy has good structural strength, and aluminum has a very small neutron scattering cross section, thus having a relatively small impact on incident neutrons.

[0112] In one embodiment, please refer to Figure 1 The first detection module 1 includes a first support base 14, which forms a first storage groove that extends through the front and rear sides. The first detector 11, the first modulator 12, and the first converter 13 are all located in the first storage groove.

[0113] The material of the first support 14 includes, but is not limited to, polyethylene.

[0114] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the outer contour shape of the projection of the first support 14 is approximately circular.

[0115] In one embodiment, the projected shape of the first storage slot is circular.

[0116] In one embodiment, please refer to Figure 1 The second detection module 2 includes a second support base 23, which forms a second storage groove that extends through the front and rear sides. The second detector 21 and the second moderator 22 are both located in the second storage groove.

[0117] The material of the second support 23 includes, but is not limited to, polyethylene.

[0118] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the outer contour shape of the projection of the second support 23 is approximately circular.

[0119] In one embodiment, the projected shape of the second storage slot is circular.

[0120] In one embodiment, please refer to Figure 1 The third detection module 3 includes a third support base 34, which forms a third storage groove that extends through the front and rear sides. The third detector 31, the third modulator 32, and the second converter 33 are all located in the third storage groove.

[0121] The material of the third support 34 includes, but is not limited to, polyethylene.

[0122] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the outer contour shape of the projection of the third support 34 is approximately circular.

[0123] In one embodiment, the projected shape of the third storage slot is circular.

[0124] In one embodiment, please refer to Figure 1 The anti-coincidence detection module 4 includes a fourth support base 44, which forms a fourth storage slot that extends through the front and rear sides. The anti-coincidence detector 41, the fourth moderator 42, and the third converter 43 are all located in the fourth storage slot.

[0125] The material of the fourth support 44 includes, but is not limited to, polyethylene.

[0126] In one embodiment, the projection plane is a plane perpendicular to the front-back direction, and the outer contour shape of the projection of the fourth support 44 is approximately circular.

[0127] In one embodiment, the projected shape of the fourth storage slot is circular.

[0128] In some embodiments, the first detection module 1 and the first slowing package 5 are used as a first module. The first module can have a size of 5mm in the front-back direction. The projection plane is a plane perpendicular to the front-back direction, and the projection outline of the first module is a circle with a diameter of 20mm.

[0129] In some embodiments, the second detection module 2 and the second slowing-down wrapper 6 serve as a second module. The second module can have a size of 5 mm along the front-back direction, and the projection plane perpendicular to the front-back direction is used as the projection surface. The projection outline of the second module is a circle with a diameter of 20 mm.

[0130] In some embodiments, the third detection module 3 and the second absorption package 8 serve as the third module. The third module can have a size of 5 mm along the front-back direction, and the projection plane perpendicular to the front-back direction is the projection surface. The projection outline of the third module is a circle with a diameter of 20 mm.

[0131] In some embodiments, the anti-coincidence detection module 4 and the first absorbent encapsulator 7 serve as an anti-coincidence module. The anti-coincidence module can have a size of 5 mm along the front-back direction, and the projection plane perpendicular to the front-back direction is used as the projection surface. The projected outline shape of the anti-coincidence module is a circle with a diameter of 20 mm.

[0132] In one embodiment, the overall weight of the neutron personal dosimeter is approximately 50g to 200g. Exemplary examples include overall weights of 50g, 60g, 70g, 80g, 90g, 100g, 150g, or 200g, etc. This lightweight design makes it suitable for everyday personal use.

[0133] In one embodiment, the outer shell 9 may be generally hexahedral in shape.

[0134] In one embodiment, the outer casing 9 can have a front-to-back dimension of 20 mm to 25 mm.

[0135] In one embodiment, the length of the outer casing 9 can be 60 mm, and the width of the outer casing 9 can be 40 mm.

[0136] This application embodiment also provides a direct reading mode for a neutron personal dosimeter. The basis of the direct reading mode is the difference in response of the first detection module 1, the second detection module 2, and the third detection module 3 to neutrons of different energies after anti-coincidence detection module 4.

[0137] The neutron personal dosimeter provided in this application divides the neutron energy region into three energy regions: low-energy neutron, medium-energy neutron, and fast neutron. In direct-reading mode, it can provide the personal dose equivalent for each of the three energy regions: 0.025 eV to 1 keV, 1 keV to 1 MeV, and 1 MeV to 100 MeV. Furthermore, the personal dose equivalents for the three energy regions can be summed to obtain the personal dose equivalent for neutrons in the full energy region. Therefore, the personal dose equivalent H of neutrons in the full energy region... p (10) is the sum of the individual dose equivalents of the three energy regions mentioned above, and the count M of neutrons in the all-energy region is also the sum of the counts of the three energy regions mentioned above.

[0138] Personal dose equivalent H of neutrons in the full-range region p (10) is expressed as calculation formula (1).

[0139] H p (10)=H p (10) low +H p (10)inter +H p (10) fast (1)

[0140] In equation (1), H p (10) low This refers to the individual dose equivalent of a low-energy neutron;

[0141] H p (10) inter This refers to the individual dose equivalent in the medium-energy neutron energy region;

[0142] H p (10) fast This refers to the individual dose equivalent in the fast neutron energy region.

[0143] For ease of description, in the embodiments of this application, low-energy neutrons are represented by the subscript "low", medium-energy neutron regions are represented by the subscript "inter", and fast neutron regions are represented by the subscript "fast". That is to say, parameters such as personal dose equivalent, count, and average fluence response in different energy regions are distinguished by subscripts. If there is no such subscript, it represents the parameters of neutrons in the full energy region, which will not be described again later.

[0144] For a single detection module, the count M of neutrons in the full-energy region is expressed as formula (2).

[0145] M = M low +M inter +M fast (2)

[0146] Furthermore, according to the definition of fluence response, the count of a single detection module is equal to the integral of the product of the neutron fluence per unit energy interval and the fluence response of the corresponding energy interval over the entire energy range:

[0147] M=∫φ E (E)R(E)dE (3)

[0148] Discretizing equation (3), we can approximate the count of the detection module as the sum of the products of the counts in the three energy regions and the corresponding average fluence responses:

[0149]

[0150] In equation (4), These represent the average fluence responses of the detection module to the low-energy neutron region, the medium-energy neutron region, and the fast neutron region, respectively. The average fluence response can be obtained through Monte Carlo calculations or monoenergetic fluence response calibration experiments.

[0151] The responses of the first detection module 1, the second detection module 2, and the third detection module 3 differ slightly for neutrons of different energies.

[0152] Applying equation (4) to the first detection module 1, we can obtain:

[0153]

[0154] In equation (5), the subscript 1 is used to represent the first detection module 1.

[0155] Applying equation (4) to the second detection module 2, we can obtain:

[0156]

[0157] In equation (6), the subscript 2 is used to represent the second detection module 2.

[0158] Applying equation (4) to the third detection module 3, we can obtain:

[0159]

[0160] In equation (7), the subscript 3 is used to represent the third detection module 3.

[0161] The individual dose equivalent in the fast neutron energy region can be obtained from equation (6), see equation (8):

[0162]

[0163] Subtracting equation (5) from equation (7) yields:

[0164]

[0165] Because the third detection module 3 is closer to the human body than the first detection module, it is more affected by human body albedo. Under these conditions, the responses of the first detection module 1 and the third detection module 3 are not significantly different in the low-energy neutron and fast neutron regions, but show a significant difference in the medium-energy neutron region. Therefore, it can be assumed that the number of fast neutrons and the number of low-energy neutrons produced by the first detection module 1 and the third detection module 3 are the same, i.e., in equation (9). All can be approximated to zero. Equation (9) can be transformed into equation (10):

[0166]

[0167] Substituting the results of equations (8) and (10) into equation (5), the individual dose equivalent in the low-energy neutron region can be calculated:

[0168]

[0169] Therefore, the neutron personal dosimeter provided in this application embodiment can also obtain the personal dose equivalent in the low-energy neutron region, the medium-energy neutron region and the fast neutron region respectively. Of course, the personal dose equivalent in the three regions can also be added together to obtain the personal dose equivalent in the full-energy region.

[0170] The basic principle of the anti-coincidence method of the anti-coincidence detection module 4 provided in this application embodiment is as follows: When a high-energy charged particle passes through a neutron personal dosimeter, since the energy of the high-energy charged particle is sufficient to pass through the first detection module 1, the second detection module 2, the anti-coincidence detection module 4, and the third detection module 3 simultaneously, when the anti-coincidence detection module 4 generates a signal, this signal is considered to be a charged particle signal caused by a high-energy charged particle event. The signals of the first detection module 1, the second detection module 2, and the third detection module 3 within the anti-coincidence time window are not considered neutron signals and do not contribute to the measurement result of the neutron personal dose equivalent. That is to say, during the data processing, the data within the anti-coincidence time window is removed. For example, during the processing of the personal dose equivalent of the first detection module 1, the second detection module 2, and the third detection module 3, if the first detection module 1, the second detection module 2, the anti-coincidence detection module 4, and the third detection module 3 all generate signals, then the data of the first detection module 1, the second detection module 2, and the third detection module 3 within that time period are removed.

[0171] In some embodiments, the anti-coincidence time window of the anti-coincidence detection module 4 is 50 μs to 100 μs. Exemplary examples include anti-coincidence time windows of 50 μs, 60 μs, 70 μs, 90 μs, or 100 μs, etc. In the anti-coincidence method, if the anti-coincidence time window is too large, it may increase the number of accidental coincidences, leading to a lower measured value of the individual dose equivalent. Conversely, a small window may cause charged particle signals to be mixed into the neutron signal, leading to a higher measured value of the individual dose equivalent. The anti-coincidence time window of the anti-coincidence detection module 4, at 50 μs to 100 μs, is of moderate duration and can improve measurement accuracy.

[0172] Understandably, due to the addition of the anti-coincidence function, the first detection module 1, the second detection module 2, the anti-coincidence detection module 4, and the third detection module 3, in addition to needing to obtain energy information during the measurement process, also need to add timestamp information to facilitate the anti-coincidence of the electrical signals of the first detection module 1, the second detection module 2, the anti-coincidence detection module 4, and the third detection module 3. The addition of timestamp information can employ known techniques, which will not be elaborated upon in this application.

[0173] In some embodiments, the neutron personal dosimeter of this application may also have a spectral interpretation mode, which can obtain the neutron energy spectrum. For example, the energy angle of the recoil proton is related to the neutron energy, and the fast neutron energy spectrum can be deduced by the spectral interpretation method to obtain a more accurate personal dose equivalent.

[0174] The specific spectral interpretation method can be a known method, which will not be elaborated in this application.

[0175] In some embodiments, the neutron personal dosimeter has a display screen disposed within the housing 9, which can be used to display the personal dose equivalent. This allows for real-time display of the personal dose equivalent, facilitating timely acquisition of measurement results.

[0176] In some embodiments, the neutron personal dosimeter also includes an electronics system for providing voltage to the first detection module 1, the second detection module 2, the third detection module 3, and the anti-coincidence detection module 4, and analyzing electrical signals.

[0177] The electronic system may include a preamplifier 10, a main amplifier, a power supply, and a multichannel analyzer, etc. The electrical signal enters the multichannel analyzer via the preamplifier 10 and the main amplifier.

[0178] The preamplifier 10, main amplifier, power supply and multichannel analyzer, etc. can all be well-known devices, and will not be described in detail in this application.

[0179] In the description of this application, the use of terms such as "in one embodiment," "in some embodiments," or "exemplary" indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the embodiments of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine the different embodiments or examples described in this application, as well as the features of the different embodiments or examples.

[0180] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A personal neutron dosimeter, characterized by, include: The first detection module is used to measure neutrons in the entire energy range; The second detection module is located behind the first detection module, and the second detection module is used to measure fast neutrons; An anti-coincidence detection module is disposed on the rear side of the second detection module, and the anti-coincidence detection module is used to identify high-energy charged particles in space; The third detection module is located behind the anti-coincidence detection module. The third detection module is used to measure neutrons in the full energy range. The sensitivity of the third detection module to medium-energy neutrons is higher than that of the first detection module. A first slowing-down package encloses at least a portion of the first detection module; The second slowing-down package encloses at least a portion of the second detection module; A first absorbent package encapsulates at least a portion of the anti-coincidence detection module; The second absorbent package encloses at least a portion of the third detection module; The anti-coincidence detection module includes an anti-coincidence detector, a fourth moderator, and a third converter, wherein the fourth moderator, the third converter, and the anti-coincidence detector are stacked from front to back; The anti-coincidence detection module has an anti-coincidence time window of 50μs to 100μs.

2. The personal neutron dosimeter of claim 1, wherein The first detection module includes a first detector, a first moderator, and a first converter, which are stacked from front to back.

3. The personal neutron dosimeter of claim 1, wherein The second detection module includes a second detector and a second moderator, with the second moderator disposed in front of the second detector.

4. The personal dosimeter of claim 1, wherein, The third detection module includes a third detector, a third moderator, and a second converter, which are stacked from front to back.

5. The personal dosimeter according to any one of claims 1 to 4, characterized in that The neutron personal dosimeter includes a housing with a mounting cavity, in which the first detection module, the second detection module, the third detection module, and the anti-coincidence detection module are all disposed.

6. The personal dosimeter of claim 5, wherein, The neutron personal dosimeter includes a preamplifier disposed within the housing, and the first detection module, the second detection module, the third detection module, and the anti-coincidence detection module are each electrically connected to one of the preamplifiers.

7. The personal dosimeter of claim 5, wherein, The thickness of the outer shell is 1 mm to 3 mm.

8. The personal dosimeter of claim 5, wherein, The outer shell is made of aluminum alloy.

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