Wide-range integrated out-of-pile neutron detector

Abstract

The invention discloses a wide-range integrated out-of-pile neutron detector, which adopts a coaxial multi-pole plate structure, realizes working area separation through a common electrode, and outputs a pulse signal and a current signal at the same time. Wherein the coaxial multi-pole plate structure is a coaxial multi-pole plate structure with three layers of electrode tubes additionally arranged on a central anode wire, the three layers of electrode tubes are a tube I, a tube II and a tube III in sequence from inside to outside, a pulse signal is led out by the central anode wire, and a current signal is led out by the tube II. The inner wall of the tube I and the inner wall of the tube III are coated with neutron sensitive materials; working gas suitable for the proportional counter tube is filled in the tube I, and same working gas suitable for compensating the ionization chamber is filled between the tube I and the tube II and between the tube II and the tube III. The central anode wire is connected with positive high voltage, the tube I is connected with negative high voltage, the tube II is grounded, and the tube III is connected with the positive high voltage. On the premise that the size of the detector body is not enlarged, wide-range neutron fluence rate measurement is achieved.

Description

Technical Field

[0001] The present invention relates to the field of reactor neutron fluence rate measurement, and in particular to a wide-range integrated ex-core neutron detector. Background Art

[0002] Neutron detectors are a type of nuclear radiation sensor. Neutron detectors are devices used to detect neutron radiation. They detect charged particles or nuclear reaction products produced by the interaction between neutrons and matter.

[0003] In most current reactors, neutron fluence rates are generally divided into three ranges: source range, intermediate range, and power range, depending on the different measurement requirements from reactor startup to full power operation. Different neutron detectors are used for measurement. The source range generally uses a proportional counter tube, the intermediate range uses a compensated boron-coated ionization chamber, and the power range uses a non-compensated boron-coated ionization chamber. The neutron fluence rate level in the source range is lower, while the neutron fluence rate range in the intermediate range and power range is similar. The power range uses a multi-segment non-compensated boron-coated ionization chamber to enable axial power distribution monitoring.

[0004] Under the premise of considering safety and reliability, for traditional reactor types, it is usually required to arrange 4 detectors in each range, and a total of 12 detectors are set up in three ranges; for miniaturized reactors, there is no need to measure axial power distribution, and usually 4 detectors are arranged in the source range and the intermediate range, for a total of 8 detectors. The number of extra-core neutron detectors is large and the system is complex.

[0005] In addition, fission ionization chambers can be used in the source range and intermediate range. However, fission ionization chambers face problems such as high fission material control, low neutron sensitivity, and strong fission material irradiation.

[0006] In view of this, this application is hereby filed. Summary of the Invention

[0007] The technical problem addressed by this invention is that existing neutron detector technology is unable to achieve wide-range neutron fluence rate measurement with a single detector. Reactor ex-core nuclear measurement systems often require numerous detectors, typically requiring up to 12, resulting in a complex system layout that fails to meet the demand for miniaturization of ex-core nuclear measurement systems. The present invention aims to provide a wide-range, integrated ex-core neutron detector that can measure neutron fluence rates over a range of over 10 orders of magnitude (covering the source, intermediate, and power ranges) without increasing the size of the detector body (no larger than 70 mm in diameter and no larger than 1 m in height), suitable for use in ex-core nuclear measurement system design. This invention reduces the number of ex-core detectors to eight or fewer, lowering the requirements for detector layout and providing an important technical foundation for the subsequent development of highly integrated and compact small reactors.

[0008] The present invention is achieved through the following technical solutions: A wide-range integrated ex-pile neutron detector, which adopts a coaxial multi-electrode structure, separates the working areas through a common electrode, and simultaneously outputs a pulse signal corresponding to a low neutron fluence rate and a current signal corresponding to a high neutron fluence rate; Among them, the coaxial multipolar plate structure is a coaxial multipolar plate structure with a central anode wire and three layers of electrode tubes. The three layers of electrode tubes are tube I, tube II and tube III from the inside to the outside. The pulse signal is drawn from the central anode wire, and the current signal is drawn from tube II.

[0009] The wide-range, integrated ex-pile neutron detector designed in the present invention has a coaxial multi-electrode structure. By sharing electrodes and separating the working areas, the functions of the proportional counter and the compensating ionization chamber are unified, enabling wide-range neutron fluence rate measurement without increasing the size of the detector body. The present invention can simultaneously generate a pulse signal and a current signal proportional to the neutron fluence rate, with the pulse signal corresponding to low neutron fluence rate levels and the current signal corresponding to high neutron fluence rate levels. By rationally setting parameters such as the detector structure, working gas parameters, and the composition and thickness of the neutron-sensitive coating material, the measurement range of low and high neutron fluence rates can be connected, enabling neutron fluence rate measurements exceeding 10 orders of magnitude.

[0010] Furthermore, the inner walls of the tube I and the inner walls of the tube III are both coated with neutron sensitive materials; The I tube is filled with working gas suitable for the proportional counter tube, and the space between the I tube and the II tube, and between the II tube and the III tube is filled with the same working gas suitable for the compensation ionization chamber.

[0011] Furthermore, the central anode wire is connected to positive high voltage, tube I is connected to negative high voltage, tube II is grounded, and tube III is connected to positive high voltage.

[0012] Furthermore, the present invention realizes separation of working areas by sharing the I-tube electrode, and can output pulse signals and current signals simultaneously; The pulse signal is a pulse signal proportional to the neutron fluence rate level output by the working area formed by the central anode wire and the I tube, corresponding to a low neutron fluence rate; The current signal is a current signal output by the working area formed by the I tube, the II tube and the III tube and is proportional to the neutron fluence rate level, corresponding to a high neutron fluence rate.

[0013] Furthermore, the neutron detector can achieve a range connection of two orders of magnitude between the low neutron fluence rate measurement range and the high neutron fluence rate measurement range by adjusting the detector parameters; The detector parameters include detector structure parameters, working gas parameters, and the composition and thickness of the neutron-sensitive material coating.

[0014] Furthermore, the detector structural parameters include the radius of the central anode wire, the radius of tube I, the radius of tube II and the radius of tube III; The radius of the central anode wire can be selected in the range of 10μm to 25μm; the radius of the I tube can be selected in the range of greater than 21.5mm; the radius of the III tube is selected according to the hole size; The radius of the II tube can make the distance between the I tube and the II tube slightly larger than the distance between the II tube and the III tube, and the range of the slightly larger distance is 0.5 mm to 2.5 mm.

[0015] In the above technical solution, the central anode wire was selected because a thinner wire ensures a concentrated avalanche zone and a higher electric field intensity near the wire, which facilitates the formation of a narrow, high-amplitude pulse signal. The radius of tube I was chosen because a radius greater than 21.5 mm allows for greater neutron sensitivity. The radius of tube III was chosen for ease of detector installation. The radius of tube II was chosen to optimize the detector's gamma signal compensation capability.

[0016] As a further preference, the radius of the central anode wire is 12.5 μm, the radius of tube I is 25.5 mm, the radius of tube II is 30.5 mm, and the radius of tube III is 35 mm.

[0017] Furthermore, the working gas parameters include the type of working gas and the working gas pressure; The first working gas in the I tube may include argon and isobutane, argon and ethylene, argon and trifluoromethane, or argon and carbon dioxide. The first working gas pressure ranges from 0.25 atm to 0.35 atm. The first working gas type is selected based on a comprehensive consideration of the gas's stability, average ionization energy, Townsend coefficient, and charge motion characteristics. The first working gas pressure is selected based on a comprehensive consideration of the gas's performance, ensuring a high gas multiplication characteristic and sufficient energy deposition of heavily charged particles.

[0018] The second working gas filled between tubes I and II, and between tubes II and III, is consistent. Types of the second working gas include argon and methane, argon and acetylene, argon and carbon tetrafluoride, and argon and carbon dioxide. The second working gas pressure ranges from 1 atm to 3 atm. The type of second working gas is selected based on a comprehensive consideration of its stability, average ionization energy, and charge motion characteristics. The second working gas pressure is selected to ensure sufficient deposition of heavily charged particle energy while taking into account all gas properties.

[0019] As a further preferred embodiment, the working gas filled in the I tube is 85% argon and 15% carbon dioxide, and the pressure of the first working gas is 0.3 atm; The second working gas filled between the I tube and the II tube and between the II tube and the III tube is 80% argon and 20% carbon dioxide, and the pressure of the second working gas is 1 atm.

[0020] Furthermore, the composition of the neutron sensitive material coating is 10 The boron material, with a 90% boron content, has a coating thickness ranging from 1.7μm to 3.4μm. The neutron-sensitive material composition was chosen based on its large and readily accessible thermal neutron reaction cross-section, and the coating thickness was chosen to ensure maximum neutron sensitivity.

[0021] As a further preference, the neutron sensitive material is selected 10 Boron material with 90% B content, the inner wall coating thickness of tube I is 2.1μm, and the inner wall coating thickness of tube III is 1.9μm.

[0022] The above technical solution changes the measurable range of the pulse signal measurement mode and the current signal measurement mode by adjusting the above detector parameters, thereby achieving range connection.

[0023] Furthermore, the neutron detector can achieve at least Wide range measurement of neutron fluence rate.

[0024] Furthermore, the diameter of the detector body does not exceed 70 mm, and the height does not exceed 1 m.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a wide-range integrated ex-pile neutron detector. The wide-range integrated ex-pile neutron detector designed by the present invention has a coaxial multi-pole plate structure. The design of shared electrodes and separated working areas realizes the unification of the functions of the proportional counter tube and the compensation ionization chamber, and realizes wide-range neutron fluence rate measurement without expanding the size of the detector body.

[0026] 2. The present invention provides a wide-range integrated ex-pile neutron detector, which can simultaneously generate a pulse signal and a current signal proportional to the neutron fluence rate. The pulse signal corresponds to a low neutron fluence rate level, and the current signal corresponds to a high neutron fluence rate level. By reasonably setting the detector structural parameters, working gas parameters, the composition and thickness of the neutron-sensitive coating material and other parameters, the range connection between the low neutron fluence rate and the high neutron fluence rate measurement range can be achieved, and neutron fluence rate measurement of more than 10 orders of magnitude can be achieved.

[0027] 3. The present invention provides a wide-range integrated ex-pile neutron detector. The new wide-range integrated ex-pile neutron detector covers a thermal neutron flux rate range of at least greater than , which can meet the wide-range measurement requirements of reactor neutron flux rates. The use of a new wide-range integrated ex-core neutron detector can reduce the number of ex-core detectors to eight or fewer, lowering the requirements for detector placement and providing an important technical foundation for the subsequent development of highly integrated and compact small reactors.

[0028] 4. Compared with traditional detector arrangements, while achieving the same measurement range and function, the present invention uses four wide-range, integrated ex-core neutron detectors to replace source-range and intermediate-range detectors (a total of eight). For conventional reactors, four neutron detectors designed in the present invention are required, for a total of eight detectors. For miniaturized reactors, four neutron detectors designed in the present invention are required. This significantly reduces the number of neutron detectors compared to traditional detector arrangements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 This is a schematic structural diagram of a wide-range integrated ex-pile neutron detector according to the present invention; Figure 2 This is a cross-sectional view of a wide-range integrated ex-pile neutron detector of the present invention.

[0030] Reference numerals and corresponding component names: 1-Center anode wire, 2-I tube, 3-II tube, 4-III tube. DETAILED DESCRIPTION

[0031] Hereinafter, the terms "include" or "may include" used in various embodiments of the present invention indicate the presence of the invented function, operation or element, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing, and should not be understood as excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing.

[0032] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0033] The expressions (such as "first", "second", etc.) used in the various embodiments of the present invention may modify the various constituent elements in the various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used to distinguish one element from other elements. For example, a first user device and a second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present invention, a first element may be referred to as a second element, and similarly, a second element may also be referred to as a first element.

[0034] It should be noted that when a component is described as being “connected” to another component, the first component may be directly connected to the second component, and a third component may be “connected” between the first and second components. Conversely, when a component is described as being “directly connected” to another component, it can be understood that there is no third component between the first and second components.

[0035] The terms used in various embodiments of the present invention are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments of the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as those of ordinary skill in the art generally understood by the various embodiments of the present invention. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having idealized meaning or too formal meaning, unless clearly defined in various embodiments of the present invention.

[0036] 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 examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0037] Under the premise of considering safety and reliability, for traditional reactor types, it is usually required to arrange 4 detectors in each range, and a total of 12 detectors are set up in three ranges; for miniaturized reactors, there is no need to measure axial power distribution, and usually 4 detectors are arranged in the source range and the intermediate range, for a total of 8 detectors. The number of extra-core neutron detectors is large and the system is complex.

[0038] Therefore, considering that as the reactor develops towards miniaturization and high integration, the present invention designs a new wide-range integrated off-core neutron detector. The neutron detector of the present invention adopts a coaxial multi-pole plate structure, which is composed of a central anode wire, tube I, tube II, and tube III. Neutron sensitive materials are coated on the inner walls of tubes I and III. The central anode wire is connected to positive high voltage, tube I is connected to negative high voltage, tube II is grounded, and tube III is connected to positive high voltage. The proportional counter tube working gas is filled in tube I, and the same compensation ionization chamber working gas is filled between tubes I and II, and between tubes II and III. The working area separation is achieved by sharing the electrode of tube I, and the pulse signal and the current signal can be output simultaneously, which can achieve at least The wide-range integrated ex-pile neutron detector can reduce the number of ex-pile detectors to eight or fewer, providing an important technical foundation for the subsequent development of highly integrated and compact small reactors.

[0039] Compared to traditional detector arrangements, while achieving the same measurement range and functionality, the present invention uses four wide-range, integrated ex-core neutron detectors to replace source-range and intermediate-range detectors (a total of eight). For conventional reactors, four neutron detectors designed in this invention are required, for a total of eight detectors. For miniaturized reactors, four neutron detectors are required. This significantly reduces the number of neutron detectors compared to traditional detector arrangements.

[0040] Example 1 like Figure 1 and Figure 2 As shown, a wide-range integrated ex-core neutron detector of this embodiment adopts a coaxial multi-electrode plate structure, realizes separation of working areas through a common electrode, and simultaneously outputs a pulse signal corresponding to a low neutron fluence rate and a current signal corresponding to a high neutron fluence rate; Among them, the coaxial multipolar plate structure is a coaxial multipolar plate structure with a central anode wire and three layers of electrode tubes. The three layers of electrode tubes are tube I, tube II and tube III from the inside to the outside. The pulse signal is drawn from the central anode wire, and the current signal is drawn from tube II.

[0041] In this embodiment, the coaxial multi-electrode plate structure is a three-layer nested cylindrical structure formed with the central anode wire as the central axis. The central anode wire is arranged in the center of tube I, tube II surrounds tube I, and tube III surrounds tube II. The three layers of electrode tubes are coaxial and share the central anode wire as the central axis.

[0042] In this embodiment, the inner walls of tubes I and III are both coated with neutron-sensitive materials. Tube I is filled with a working gas suitable for a proportional counter tube, and the spaces between tubes I and II, and between tubes II and III, are filled with the same working gas suitable for compensating ionization chambers. The central anode wire is connected to a positive high voltage, tube I is connected to a negative high voltage, tube II is grounded, and tube III is connected to a positive high voltage. A pulse signal is derived from the central anode wire, and a current signal is derived from tube II.

[0043] In this embodiment, the present invention realizes separation of the working area by sharing the I tube electrode, and can simultaneously output a pulse signal and a current signal; the working area formed by the central anode wire and the I tube outputs a pulse signal proportional to the neutron fluence rate level, corresponding to a low neutron fluence rate; the working area formed by the I tube, the II tube and the III tube outputs a current signal proportional to the neutron fluence rate level, corresponding to a high neutron fluence rate.

[0044] The wide-range integrated ex-pile neutron detector designed by the present invention is a coaxial multi-electrode plate structure. The design of shared electrodes and separated working areas realizes the unification of the functions of the proportional counter tube and the compensation ionization chamber. Without increasing the size of the detector body (diameter not exceeding 70mm, height not exceeding 1m), at least The present invention can simultaneously generate a pulse signal and a current signal proportional to the neutron fluence rate. The pulse signal corresponds to a low neutron fluence rate level, and the current signal corresponds to a high neutron fluence rate level. By properly setting parameters such as the detector structure parameters, the working gas parameters, and the composition and thickness of the neutron-sensitive coating material, the measurement range of low and high neutron fluence rates can be connected, enabling neutron fluence rate measurements over more than 10 orders of magnitude.

[0045] Example 2 like Figure 1 and Figure 2 As shown, a wide-range integrated ex-core neutron detector of this embodiment adopts a coaxial multi-electrode plate structure, realizes separation of working areas through a common electrode, and simultaneously outputs a pulse signal corresponding to a low neutron fluence rate and a current signal corresponding to a high neutron fluence rate; Among them, the coaxial multipolar plate structure is a coaxial multipolar plate structure with a central anode wire and three layers of electrode tubes. The three layers of electrode tubes are tube I, tube II and tube III from the inside to the outside. The pulse signal is drawn from the central anode wire, and the current signal is drawn from tube II.

[0046] In this embodiment, the coaxial multi-electrode plate structure is a three-layer nested cylindrical structure formed with the central anode wire as the central axis. The central anode wire is arranged in the center of tube I, tube II surrounds tube I, and tube III surrounds tube II. The three layers of electrode tubes are coaxial and share the central anode wire as the central axis.

[0047] In this embodiment, the inner walls of tubes I and III are both coated with neutron-sensitive materials. Tube I is filled with a working gas suitable for a proportional counter tube, and the spaces between tubes I and II, and between tubes II and III, are filled with the same working gas suitable for compensating ionization chambers. The central anode wire is connected to a positive high voltage, tube I is connected to a negative high voltage, tube II is grounded, and tube III is connected to a positive high voltage. A pulse signal is derived from the central anode wire, and a current signal is derived from tube II.

[0048] In this embodiment, the present invention realizes separation of the working area by sharing the I tube electrode, and can simultaneously output a pulse signal and a current signal; the working area formed by the central anode wire and the I tube outputs a pulse signal proportional to the neutron fluence rate level, corresponding to a low neutron fluence rate; the working area formed by the I tube, the II tube and the III tube outputs a current signal proportional to the neutron fluence rate level, corresponding to a high neutron fluence rate.

[0049] In this embodiment, the neutron detector achieves a range connection of two orders of magnitude between the low neutron fluence rate measurement range and the high neutron fluence rate measurement range by adjusting the detector parameters; The detector parameters include detector structure parameters, working gas parameters, and the composition and thickness of the neutron-sensitive material coating.

[0050] Specifically, the detector structural parameters include the radius of the central anode wire, the radius of tube I, the radius of tube II, and the radius of tube III; The radius of the central anode wire can be selected in the range of 10μm to 25μm; the radius of the I tube can be selected in the range of greater than 21.5mm; the radius of the III tube is selected according to the hole size; The radius of the II tube can make the distance between the I tube and the II tube slightly larger than the distance between the II tube and the III tube, and the range of the slightly larger distance is 0.5 mm to 2.5 mm.

[0051] In the above technical solution, the central anode wire was selected because a thinner wire ensures a concentrated avalanche zone and a higher electric field intensity near the wire, which facilitates the formation of a narrow, high-amplitude pulse signal. The radius of tube I was chosen because a radius greater than 21.5 mm allows for greater neutron sensitivity. The radius of tube III was chosen for ease of detector installation. The radius of tube II was chosen to optimize the detector's gamma signal compensation capability.

[0052] In this embodiment, the working gas parameters include the type of working gas and the working gas pressure; The first working gas in the I tube may include argon and isobutane, argon and ethylene, argon and trifluoromethane, or argon and carbon dioxide. The first working gas pressure ranges from 0.25 atm to 0.35 atm. The first working gas type is selected based on a comprehensive consideration of the gas's stability, average ionization energy, Townsend coefficient, and charge motion characteristics. The first working gas pressure is selected based on a comprehensive consideration of the gas's performance, ensuring a high gas multiplication characteristic and sufficient energy deposition of heavily charged particles.

[0053] The second working gas filled between tubes I and II, and between tubes II and III, is consistent. Types of the second working gas include argon and methane, argon and acetylene, argon and carbon tetrafluoride, and argon and carbon dioxide. The second working gas pressure ranges from 1 atm to 3 atm. The type of second working gas is selected based on a comprehensive consideration of its stability, average ionization energy, and charge motion characteristics. The second working gas pressure is selected to ensure sufficient deposition of heavily charged particle energy while taking into account all gas properties.

[0054] In this embodiment, the composition of the neutron sensitive material coating is 10 The boron material, with a 90% boron content, has a coating thickness ranging from 1.7μm to 3.4μm. The neutron-sensitive material composition was chosen based on its large and readily accessible thermal neutron reaction cross-section, and the coating thickness was chosen to ensure maximum neutron sensitivity.

[0055] The above technical solution changes the measurable range of the pulse signal measurement mode and the current signal measurement mode by adjusting the above detector parameters, thereby achieving range connection.

[0056] Example 3 like Figure 1 and Figure 2 As shown, a wide-range integrated ex-core neutron detector of this embodiment adopts a coaxial multi-electrode plate structure, realizes separation of working areas through a common electrode, and simultaneously outputs a pulse signal corresponding to a low neutron fluence rate and a current signal corresponding to a high neutron fluence rate; Among them, the coaxial multipolar plate structure is a coaxial multipolar plate structure with a central anode wire and three layers of electrode tubes. The three layers of electrode tubes are tube I, tube II and tube III from the inside to the outside. The pulse signal is drawn from the central anode wire, and the current signal is drawn from tube II.

[0057] In this embodiment, the coaxial multi-electrode plate structure is a three-layer nested cylindrical structure formed with the central anode wire as the central axis. The central anode wire is arranged in the center of tube I, tube II surrounds tube I, and tube III surrounds tube II. The three layers of electrode tubes are coaxial and share the central anode wire as the central axis.

[0058] In this embodiment, the inner walls of tubes I and III are both coated with neutron-sensitive materials. Tube I is filled with a working gas suitable for a proportional counter tube, and the spaces between tubes I and II, and between tubes II and III, are filled with the same working gas suitable for compensating ionization chambers. The central anode wire is connected to a positive high voltage, tube I is connected to a negative high voltage, tube II is grounded, and tube III is connected to a positive high voltage. A pulse signal is derived from the central anode wire, and a current signal is derived from tube II.

[0059] In this embodiment, the present invention realizes separation of the working area by sharing the I tube electrode, and can simultaneously output a pulse signal and a current signal; the working area formed by the central anode wire and the I tube outputs a pulse signal proportional to the neutron fluence rate level, corresponding to a low neutron fluence rate; the working area formed by the I tube, the II tube and the III tube outputs a current signal proportional to the neutron fluence rate level, corresponding to a high neutron fluence rate.

[0060] In this embodiment, the neutron detector achieves a range connection of two orders of magnitude between the low neutron fluence rate measurement range and the high neutron fluence rate measurement range by adjusting the detector parameters; The detector parameters include detector structure parameters, working gas parameters, and the composition and thickness of the neutron-sensitive material coating.

[0061] Specifically, the detector structural parameters include the radius of the central anode wire, the radius of tube I, the radius of tube II, and the radius of tube III; In this embodiment, the radius of the central anode wire is 12.5 μm, the radius of tube I is 25.5 mm, the radius of tube II is 30.5 mm, and the radius of tube III is 35 mm.

[0062] Specifically, the working gas filled in the I tube is 85% argon and 15% carbon dioxide, and the pressure of the first working gas is 0.3 atm; The second working gas filled between the I tube and the II tube and between the II tube and the III tube is 80% argon and 20% carbon dioxide, and the pressure of the second working gas is 1 atm.

[0063] Specifically, neutron sensitive materials are selected 10 Boron material with 90% B content, the inner wall coating thickness of tube I is 2.1μm, and the inner wall coating thickness of tube III is 1.9μm.

[0064] The above technical solution changes the measurable range of the pulse signal measurement mode and the current signal measurement mode by adjusting the above detector parameters, thereby achieving range connection.

[0065] The wide-range integrated ex-pile neutron detector designed by the present invention is a coaxial multi-electrode plate structure. The design of shared electrodes and separated working areas realizes the unification of the functions of the proportional counter tube and the compensation ionization chamber. Without increasing the size of the detector body (diameter not exceeding 70mm, height not exceeding 1m), at least The present invention can simultaneously generate a pulse signal and a current signal proportional to the neutron fluence rate. The pulse signal corresponds to a low neutron fluence rate level, and the current signal corresponds to a high neutron fluence rate level. By properly setting parameters such as the detector structure parameters, the working gas parameters, and the composition and thickness of the neutron-sensitive coating material, the measurement range of low and high neutron fluence rates can be connected, enabling neutron fluence rate measurements over more than 10 orders of magnitude.

[0066] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wide-range integrated ex-pile neutron detector, characterized in that: The neutron detector adopts a coaxial multi-electrode plate structure, realizes the separation of working areas through common electrodes, and outputs pulse signals and current signals simultaneously; Among them, the coaxial multipolar plate structure is a coaxial multipolar plate structure with a central anode wire and three layers of electrode tubes. The three layers of electrode tubes are tube I, tube II and tube III from the inside to the outside. The pulse signal is drawn from the central anode wire, and the current signal is drawn from tube II.

2. The wide-range integrated ex-core neutron detector according to claim 1, characterized in that: The inner walls of tube I and tube III are both coated with neutron sensitive materials; The I tube is filled with working gas suitable for the proportional counter tube, and the space between the I tube and the II tube, and between the II tube and the III tube is filled with the same working gas suitable for the compensation ionization chamber.

3. The wide-range integrated ex-core neutron detector according to claim 2, characterized in that: The central anode wire is connected to positive high voltage, tube I is connected to negative high voltage, tube II is grounded, and tube III is connected to positive high voltage.

4. The wide-range integrated ex-core neutron detector according to claim 1, characterized in that: The pulse signal is a pulse signal proportional to the neutron fluence rate level output by the working area formed by the central anode wire and the I tube, corresponding to a low neutron fluence rate; The current signal is a current signal output by the working area formed by the I tube, the II tube and the III tube and is proportional to the neutron fluence rate level, corresponding to a high neutron fluence rate.

5. The wide-range integrated ex-core neutron detector according to claim 4, characterized in that: The neutron detector can achieve a two-order-of-magnitude range connection between low neutron fluence rate measurement and high neutron fluence rate measurement range by adjusting the detector parameters. The detector parameters include detector structure parameters, working gas parameters, and the composition and thickness of the neutron-sensitive material coating.

6. The wide-range integrated ex-core neutron detector according to claim 5, characterized in that: The detector structural parameters include the radius of the central anode wire, the radius of tube I, the radius of tube II and the radius of tube III; The radius of the central anode wire is 10 μm to 25 μm; the radius of the I tube is greater than 21.5 mm; the radius of the III tube is selected according to the channel size; The radius of the II tube can make the distance between the I tube and the II tube slightly larger than the distance between the II tube and the III tube, and the range of the slightly larger distance is 0.5 mm to 2.5 mm.

7. The wide-range integrated ex-core neutron detector according to claim 6, characterized in that: The radius of the central anode wire is 12.5 μm, the radius of tube I is 25.5 mm, the radius of tube II is 30.5 mm, and the radius of tube III is 35 mm.

8. The wide-range integrated ex-core neutron detector according to claim 5, characterized in that: The working gas parameters include the type of working gas and the working gas pressure; The first working gas in the I tube includes argon and isobutane, argon and ethylene, argon and trifluoromethane, and argon and carbon dioxide; the pressure range of the first working gas is 0.25 atm to 0.35 atm; The second working gas filled between tubes I and II and between tubes II and III is consistent. The types of the second working gas include argon and methane, argon and acetylene, argon and carbon tetrafluoride, and argon and carbon dioxide; the pressure range of the second working gas is 1atm~3atm.

9. The wide-range integrated ex-core neutron detector according to claim 8, characterized in that: The working gas filled in the I tube is 85% argon and 15% carbon dioxide, and the pressure of the first working gas is 0.3 atm; The second working gas filled between the I tube and the II tube and between the II tube and the III tube is 80% argon and 20% carbon dioxide, and the pressure of the second working gas is 1 atm.

10. The wide-range integrated ex-core neutron detector according to claim 5, characterized in that: The composition of the neutron sensitive material coating is 10 Boron material with a B content of 90% has a coating thickness ranging from 1.7μm to 3.4μm.

11. The wide-range integrated ex-core neutron detector according to claim 1, characterized in that: The neutron detector can achieve at least Wide range measurement of neutron fluence rate.

12. The wide-range integrated ex-core neutron detector according to claim 11, characterized in that: The diameter of the detector body does not exceed 70 mm and the height does not exceed 1 m.

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