Measurement device and method for mixed radiation field

Abstract

The invention belongs to the technical field of nuclear radiation detection, and particularly relates to a measuring device and method for a mixed radiation field. The measuring device comprises a shell, and the shell comprises an accommodating cavity. The first high-voltage electrode and the first collecting electrode are arranged in the containing cavity of the shell in a nested mode, a first annular ionization chamber is defined by the first high-voltage electrode and the first collecting electrode, and the first annular ionization chamber is sensitive to neutrons and gamma rays. The second high-voltage electrode and the second collecting electrode are arranged in a nested mode, a second annular ionization chamber is defined by the second high-voltage electrode and the second collecting electrode, and the second annular ionization chamber is sensitive to gamma rays. And the second high-voltage electrode, the second collector, the first collector and the first high-voltage electrode are sequentially nested from inside to outside in the radial direction of the shell. According to the neutron fluence measuring device, the second high-voltage electrode, the second collector, the first collector and the first high-voltage electrode are sequentially nested from inside to outside, so that the neutron fluence rate can be accurately measured in a radiation field with relatively high gamma ray intensity and relatively low neutron intensity.

Description

Technical Field

[0001] This application belongs to the field of nuclear radiation detection technology, specifically relating to a measuring device and method for mixed radiation fields. Background Technology

[0002] In the field of nuclear radiation detection, neutrons and gamma (γ) rays are often interspersed, and neutron radiation detectors are generally sensitive to γ ​​rays. Monitoring neutron fluence often requires specialized methods, commonly including pulse amplitude discrimination and γ-ray compensation methods. For example, neutron proportional counters and pulsed fission ionization chambers use pulse amplitude discrimination, while γ-ray compensation ionization chambers use differential current to compensate for γ-ray intensity and monitor neutrons. Pulse amplitude discrimination is typically used in scenarios with low γ-ray dose rates (less than 10 Gy / h).

[0003] Theoretically, gamma compensation can achieve optimal compensation at higher gamma-ray dose rates. However, in practice, due to the inconvenience of setting the compensation voltage, truly optimal compensation is often not achieved. At higher gamma-ray dose rates (greater than 10 Gy / h), the influence of internal electric field fluctuations makes it impossible to find a suitable compensation voltage to stabilize the output at a lower level, thus failing to achieve optimal compensation and limiting the measurement lower limit. Specifically, the measurement lower limit at low dose rates is generally greater than 100 n / (cm²). 2 •s), the lower limit of measurement at high dose rates is generally greater than 10000 n / (cm²). 2 ·s). However, the application of fission ionization chambers is limited due to material constraints.

[0004] Currently, methods for measuring mixed neutron and gamma-ray radiation fields mainly include paired thermoluminescence methods, paired ionization chamber methods, gel dosimeter methods, and film dosimeter methods. Among these, the paired ionization chamber method is recommended by the International Commission on Radiation Units (ICRU) as the standard measurement method. However, these methods struggle to accurately distinguish and measure different types of neutron fluence rates in complex mixed radiation fields, especially under rapidly changing neutron fluence rates and complex radiation environments, where the measurement accuracy often falls short of practical application requirements. Complex radiation environments such as reactor external vents, photo-induced neutron source exits, and boron neutron capture therapy often contain multiple radiation components, including thermal neutrons, fast neutrons, and gamma rays, forming mixed radiation fields. This complex radiation environment places higher demands on detector sensitivity and measurement accuracy, especially when gamma intensity is high (exposure rate greater than 1000 Gy / h) and neutron intensity is low (neutron fluence rate less than 1 × 10⁻⁶ Gy / h). 3 Up to 1×10 6 n / (cm 2In application scenarios such as after a reactor design accident, existing testing methods cannot accurately measure the neutron flux rate. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the related art.

[0006] Therefore, the first aspect of this application provides a measuring device for mixed radiation fields.

[0007] A second aspect of this application provides a method for measuring mixed radiation fields.

[0008] According to a first aspect of the embodiments of this application, a measuring device for a mixed radiation field is provided, comprising: a housing including a receiving cavity with an opening; a first high-voltage electrode and a first collecting electrode nested within the receiving cavity of the housing, the first high-voltage electrode and the first collecting electrode defining a first annular ionization chamber, the first annular ionization chamber being sensitive to neutrons and gamma rays; a second high-voltage electrode and a second collecting electrode nested within the housing, the second high-voltage electrode and the second collecting electrode defining a second annular ionization chamber, the second annular ionization chamber being sensitive to gamma rays; the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode being nested sequentially from the inside to the outside along the radial direction of the housing.

[0009] In one possible implementation, the volume of the second annular ionization chamber is 0.5 to 2 times the volume of the first annular ionization chamber.

[0010] In one possible implementation, the measuring device further includes an isolation electrode disposed between the first collecting electrode and the second collecting electrode, and surrounding the second collecting electrode.

[0011] In one possible implementation, the measuring device further includes: a first isolation ring assembly disposed at the top of the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode; and a second isolation ring assembly disposed at the bottom of the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode.

[0012] In one possible implementation, the measuring device further includes: a clamping member disposed within the housing and near the opening, the clamping member abutting against the inner wall of the housing; a first isolation ring assembly disposed within the clamping member, and a second isolation ring assembly disposed on the side of the housing away from the opening.

[0013] In one possible implementation, the measuring device further includes: a plurality of elastic elements, each disposed within the housing and located on the side of the second isolation ring group away from the opening, one end of each elastic element being connected to the side of the second isolation ring group opposite to the first isolation ring group for shock absorption.

[0014] In one possible implementation, the inner wall of the housing is provided with a liner, and the measuring device further includes: a top cover base, disposed at the opening of the housing and connected to the liner, the top cover base being provided with a first lead-out tube, a second lead-out tube, and a third lead-out tube; a first lead-out wire, one end of which is electrically connected to the first collecting electrode, and the other end of which extends through at least the first lead-out tube to the outside of the accommodating cavity, for leading out the current signal generated on the first collecting electrode; a second lead-out wire, one end of which is electrically connected to the second collecting electrode, and the other end of which extends through at least the second lead-out tube to the outside of the accommodating cavity, for leading out the current signal generated on the second collecting electrode; and a connecting wire, one end of which is electrically connected to the first high-voltage electrode and the second high-voltage electrode respectively through branch lines, and the other end of which extends through the third lead-out tube to the outside of the accommodating cavity, for introducing an external high-voltage power supply to the first high-voltage electrode and the second high-voltage electrode.

[0015] In one possible implementation, the measuring device further includes: a plurality of transition rings, respectively disposed at the connection points of the first lead-out pipe, the second lead-out pipe and the third lead-out pipe with the top cover base, for buffering thermal stress.

[0016] According to a second aspect of the embodiments of this application, a method for measuring a mixed radiation field is proposed, comprising the following steps: in response to a measurement request, acquiring a first output current of a first collector electrode and a second output current of a second collector electrode; acquiring a neutron fluence calculation model and a gamma ray dose rate calculation model; calculating a neutron fluence rate based on the first output current and the second output current using the neutron fluence rate calculation model; and calculating a gamma ray dose rate based on the second output current using the gamma ray dose rate calculation model.

[0017] In one possible implementation, the neutron flux rate calculation model is: Φ=(Ik×I0) / Sn, where k=S γ / S γ0 The gamma ray dose rate calculation model is: X = I0 / S γ0 In the formula, Φ is the neutron fluence rate, I is the first output current, I0 is the second output current, k is the ratio of the gamma-ray response of the first annular ionization chamber to the second annular ionization chamber, Sn is the neutron sensitivity of the first annular ionization chamber, and S... γ S represents the gamma-ray sensitivity of the first annular ionization chamber.γ0 denoted as Gamma ray sensitivity of the second annular ionization chamber, and X as gamma ray dose rate.

[0018] The measuring device and method for mixed radiation fields provided in this application can achieve at least the following technical effects: In this application, the measuring device for a mixed radiation field includes a housing with an open accommodating cavity providing structural support and physical protection for internal components such as a second high-voltage electrode, a second collecting electrode, a first collecting electrode, and a first high-voltage electrode. The nested first high-voltage electrode and the first collecting electrode are disposed within the accommodating cavity of the housing, defining a first annular ionization chamber. The first annular ionization chamber is sensitive to neutrons and gamma rays and can capture the total ionization current resulting from the combined effect of neutron and gamma-ray radiation in real time. The nested second high-voltage electrode and the second collecting electrode define a second annular ionization chamber, which is also sensitive to gamma rays and can output a current signal entirely contributed by gamma-ray radiation in a mixed radiation field. By nesting the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode from the inside out along the radial direction of the shell, the first annular ionization chamber surrounds the outside of the second annular ionization chamber and almost overlaps in space. In application scenarios with high gamma ray intensity and low neutron intensity, the neutron flux rate can be measured more accurately.

[0019] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 A cross-sectional structural schematic diagram of a measuring device for a mixed radiation field provided in an embodiment of this disclosure; Figure 2 A schematic diagram showing the arrangement of the top cover base and the outlet pipe provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram showing the positional relationship of the electrodes provided in an embodiment of this disclosure; Figure 4 A three-dimensional structural schematic diagram of a measuring device for a mixed radiation field provided in an embodiment of this disclosure; Figure 5 A schematic diagram illustrating the nesting relationship between the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode provided in this embodiment of the disclosure; Figure 6A flowchart illustrating a method for measuring a mixed radiation field provided in an embodiment of this disclosure; Figure 7 A schematic diagram of the structure of the control device provided in the embodiments of this disclosure.

[0021] The reference numerals in the attached figures are as follows: 100: Measuring device; 101: Housing; 102: Opening; 103: Receiving cavity; 104: First high-voltage electrode; 105: First collecting electrode; 106: First annular ionization chamber; 107: Second high-voltage electrode; 108: Second collecting electrode; 109: Second annular ionization chamber; 110: Isolating electrode; 111: First isolation ring assembly; 112: Second isolation ring assembly; 113: Clamping element; 114: Elastic element; 115: Liner; 116: Top cover base; 117: First lead-out tube; 118: Second lead-out pipe; 119: Third lead-out pipe; 120: First lead-out wire; 121: Second lead-out wire; 122: Connecting wire; 123: Transition ring; 124: Exhaust pipe; 125: First lead-out ceramic pillar; 126: Second lead-out ceramic pillar; 127: Third lead-out ceramic pillar; 128: Fourth lead-out ceramic pillar; 129: First branch line; 130: Second branch line; 131: Outer ceramic ring; 132: Middle ceramic ring; 133: Inner ceramic ring; 134: Central ceramic pillar; 135: Base.

[0022] 800: Control device; 802: Processor; 804: Memory; 806: Communication interface; 808: Bus. Detailed Implementation

[0023] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0024] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0025] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0026] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0027] Unless otherwise stated, the term "multiple" means two or more.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0029] Combination Figures 1 to 5 As shown, this application provides a measuring device 100 for a mixed radiation field, including a housing 101, a nested first high-voltage electrode 104 and a first collecting electrode 105, and a nested second high-voltage electrode 107 and a second collecting electrode 108. The housing 101 includes a receiving cavity 103 with an opening 102. The nested first high-voltage electrode 104 and the first collecting electrode 105 are disposed within the receiving cavity 103 of the housing 101, defining a first annular ionization chamber 106, which is sensitive to neutrons and gamma rays. The nested second high-voltage electrode 107 and the second collecting electrode 108 define a second annular ionization chamber 109, which is sensitive to gamma rays. Along the radial direction of the housing 101, the second high-voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high-voltage electrode 104 are nested sequentially from the inside to the outside.

[0030] It should be noted that, Figure 5Arrow F1 in the diagram indicates the direction in which the second high-voltage electrode 107, the second collector electrode 108, the first collector electrode 105, and the first high-voltage electrode 104 are nested from the inside out.

[0031] The housing 101 includes a receiving cavity 103 with an opening 102. The housing 101 can serve as a signal ground and provide structural support and physical protection for internal components such as the collecting electrode and the high-voltage electrode. The first high-voltage electrode 104, as the outermost annular electrode, surrounds the first collecting electrode 105 and together with the first collecting electrode 105, defines a first annular ionization chamber 106 that is sensitive to neutrons and gamma rays. When a high voltage is applied to the first high-voltage electrode 104, a strong electric field is formed that runs through the entire first annular ionization chamber 106, enabling the first collecting electrode 105 to capture the total ionization current caused by the combined effect of neutron and gamma ray radiation in real time.

[0032] The second high-voltage electrode 107 serves as the innermost annular electrode. The second high-voltage electrode 107 surrounds the second collector electrode 108 and together with the second collector electrode 108, defines the second annular ionization chamber 109, which is only sensitive to gamma rays. When a high voltage is applied to the second high-voltage electrode 107, a strong electric field is formed that runs through the entire second annular ionization chamber 109, enabling independent collection of pure gamma ray signals. This allows the second collector electrode 108 to output a pure gamma ray current signal.

[0033] By nesting the second high-voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high-voltage electrode 104 from the inside out, the first annular ionization chamber 106 and the second annular ionization chamber 109 are almost completely overlapped in space. This ensures that the two ionization chambers are subjected to approximately the same gamma-ray radiation field. In application scenarios with high gamma-ray intensity and low neutron intensity, this allows for relatively accurate measurement of neutron fluence. It effectively solves the problem that existing paired ionization chamber methods cannot measure neutron fluence in situ.

[0034] It should be noted that the first annular ionization chamber 106 and the second annular ionization chamber 109 are almost spatially overlapping. That is, through the coaxial nesting design of the first annular ionization chamber 106 and the second annular ionization chamber 109, the axes of the two ionization chambers are aligned, and the two ionization chambers experience essentially the same gamma-ray radiation field. Their radiation environment can be considered to be at the same location. Since the first annular ionization chamber 106 and the second annular ionization chamber 109 are at the same location, the gamma-ray dose rate received at the same moment can be considered to be the same. Therefore, at a certain instant, the ionization current is stable, and the current flow in the electric field of each acceptor is directional.

[0035] In one possible implementation, the second high-voltage electrode 107, the second collector electrode 108, the first collector electrode 105, and the first high-voltage electrode 104 are each made of conductive material.

[0036] In one possible implementation, the inner wall of the first high-voltage electrode 104 and the outer wall of the first collector electrode 105 can both be coated with a boron layer (or plated with a solid neutron-sensitive layer such as U) as neutron-sensitive materials, making the first annular ionization chamber 106 sensitive to neutrons and gamma rays. The second high-voltage electrode 107 and the second collector electrode 108 lack neutron-sensitive materials, making the second annular ionization chamber 109 sensitive to gamma rays. This achieves the formation of independent yet nested detection sensitive regions for the first annular ionization chamber 106 and the second annular ionization chamber 109.

[0037] In one possible implementation, the shell 101 can be made of metal materials such as aluminum alloy, titanium alloy, or stainless steel, which have good radiation resistance and mechanical properties.

[0038] In one possible implementation, the housing 101, the second high-voltage electrode 107, the second collector electrode 108, the first collector electrode 105, and the first high-voltage electrode 104 are arranged substantially coaxially.

[0039] In one possible implementation, the second high-voltage electrode 107, the second collector electrode 108, the first collector electrode 105, and the first high-voltage electrode 104 can each be cylindrical, for example, they are metal cylinders. When they are cylindrical, from the outside to the inside they are the first high-voltage electrode 104, the first collector electrode 105, the isolation electrode 110, the second collector electrode 108, and the second high-voltage electrode 107, respectively, or they can be distributed in a mirror image.

[0040] For example, the specific arrangement of the mirrored distribution of the first high-voltage electrode 104, the first collector electrode 105, the second collector electrode 108, and the second high-voltage electrode 107 is as follows: the first high-voltage electrode 104, the first collector electrode 105, the second collector electrode 108, and the second high-voltage electrode 107 form a combined nested structure, and multiple such combined nested structures are provided. Multiple combined nested structures are arranged sequentially along the radial direction of the housing, achieving an alternating distribution of the first annular ionization chamber 106 and the second annular ionization chamber 109 along the radial direction of the housing. The current signals generated by the multiple first collector electrodes 105 can be output separately and then combined to obtain a first output current. The current signals generated by the multiple second collector electrodes 108 can be output separately and then combined to obtain a second output current. The connecting line 122 introduces an external high-voltage power supply to the multiple first high-voltage electrodes 104 and the multiple second high-voltage electrodes 107 through multiple branch lines. In practical applications, the position and number of the isolation electrodes 110 can be set as needed and are not specifically limited.

[0041] In related technologies, when using a gamma-ray compensated ionization chamber for measurement, at a gamma-ray irradiation dose rate of 100 Gy / h, if a compensation ratio of 1% is taken, that is, the differential method cancels 99% of the gamma-ray current, outputting only 1% of the current contributed by the gamma rays, the measurement accuracy is 10%. Without compensation, the gamma-ray sensitivity is 1 × 10⁻⁶.9 A / Gy / h, neutron sensitivity is 8×10 14 A / n / (cm 2 When the value is ·s), its lower limit of measurement is 6.25×10. 5 n / (cm 2 The current method (·s) cannot meet the measurement requirements for low neutron fluence rates. Furthermore, in differential mode, the gamma-ray compensated ionization chamber struggles to achieve a lower compensation ratio (approaching 0, i.e., completely canceling the gamma-ray effect). At a certain gamma-ray dose rate, when the compensation voltage is low, the output current of the compensated ionization chamber fluctuates over time, which is detrimental to measurement. If a fission chamber is used, there is little experience in applications with dose rates greater than 1000 Gy / h. Compared to related technologies, this embodiment uses a nested design from the inside out of the second high-voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high-voltage electrode 104, so that the first annular ionization chamber 106 and the second annular ionization chamber 109 almost completely overlap spatially. In application scenarios with high gamma-ray intensity and low neutron intensity, it can achieve more accurate measurement of the neutron fluence rate. In other words, this embodiment can simultaneously monitor the neutron fluence rate and gamma-ray dose rate when the irradiation rate is greater than 1000 Gy / h. At the same time, the measuring device 100 has been improved to accurately distinguish and measure different types of radiation intensity in complex radiation fields. These improvements will help to enhance the overall level of nuclear reactor monitoring and radiation field measurement, and ensure the safe operation of facilities such as nuclear power plants.

[0042] Combination Figure 1 As shown, in some embodiments, the volume of the second annular ionization chamber 109 is 0.5 to 2 times the volume of the first annular ionization chamber 106.

[0043] In this embodiment, the volume ratio of the second annular ionization chamber 109 to the volume ratio of the first annular ionization chamber 106 is controlled between 0.5 and 2, which can stabilize the k value within a reasonable range, making it easy to calibrate and apply, and ultimately achieving a high-precision subtraction of the output current of gamma rays in the output current of the first annular ionization chamber 106, thereby obtaining a more accurate neutron fluence measurement result.

[0044] Combination Figure 1 and Figure 3 As shown, in some embodiments, the measuring device 100 further includes an isolation electrode 110 disposed between the first collecting electrode 105 and the second collecting electrode 108, and surrounding the second collecting electrode 108.

[0045] An isolation electrode 110 is disposed between the first collector 105 and the second collector 108, achieving physical isolation between the output signals of the first collector 105 and the second collector 108, and establishing independent and non-interfering signal collection for the two annular ionization chambers. The isolation electrode 110 can be cylindrical in shape.

[0046] By designing the first annular ionization chamber 106 and the second annular ionization chamber 109 separately and employing independent signal output and isolation electrode 110 isolation technology, a multifunctional combination is achieved, expanding the measurement range and meeting the measurement requirements of neutrons and gamma rays, while improving the stability of signal output, measurement efficiency, and accuracy.

[0047] Combination Figure 1 As shown, in some embodiments, the measuring device 100 further includes a first isolation ring group 111 and a second isolation ring group 112. The first isolation ring group 111 is disposed on top of the second high-voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high-voltage electrode 104. The second isolation ring group 112 is disposed at the bottom of the second high-voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high-voltage electrode 104.

[0048] By providing a second isolation ring group 112 and a first isolation ring group 111 at the bottom and top of the second high-voltage electrode 107, the second collector electrode 108, the first collector electrode 105, and the first high-voltage electrode 104, respectively, all electrodes can maintain coaxiality along their entire length. This also improves the overall insulation strength and withstand voltage level, effectively suppressing leakage current under high voltage. The second isolation ring group 112 and the first isolation ring group 111 also achieve insulation isolation between each electrode and the housing 101, the base 135, and the clamping member 113.

[0049] In one possible implementation, the first isolation ring group 111 and the second isolation ring group 112 each include: an outer ceramic ring 131, a middle ceramic ring 132, an inner ceramic ring 133, and a central ceramic pillar 134. The outer ceramic ring 131 is located at both ends of the first high-voltage electrode 104, the middle ceramic ring 132 is located at both ends of the first collecting electrode 105, the inner ceramic ring 133 is located at both ends of the second collecting electrode 108, and the central ceramic pillar 134 is located at both ends of the second high-voltage electrode 107. This serves to insulate and isolate each electrode from the housing 101, the base 135, and the clamping member 113.

[0050] In practical applications, the base 135 and the housing 101 can be connected by welding to achieve a seal and reduce the exchange of gas with the outside world.

[0051] In one possible implementation, the first isolation ring group 111 and the second isolation ring group 112 can be made of ceramic.

[0052] Combination Figure 1As shown, in some embodiments, the measuring device 100 further includes a clamping member 113, which is disposed within the housing 101 and near the opening 102, and abuts against the inner wall of the housing 101. A first isolation ring group 111 is disposed on the clamping member 113, and a second isolation ring group 112 is disposed on the side of the housing 101 away from the opening 102.

[0053] By setting the clamping member 113, the clamping and positioning of each electrode inside the accommodating cavity 103 is achieved and maintained. The clamping force of the clamping member 113 eliminates the small assembly gaps between each electrode and the first isolation ring group 111 and the second isolation ring group 112, making them fit tightly together.

[0054] In one possible implementation, the clamping member 113 has an air hole on the side near the opening 102 for introducing working gas into the accommodating cavity 103 so that the space between the electrodes is filled with working gas.

[0055] Combination Figure 1 As shown, in some embodiments, the measuring device 100 further includes a plurality of elastic elements 114, which are respectively disposed in the housing 101 and located on the side of the second isolation ring group 112 away from the opening 102. One end of the elastic element 114 is connected to the side of the second isolation ring group 112 away from the first isolation ring group 111 for shock absorption.

[0056] Combination Figure 1 As shown, by installing the elastic element 114 at the bottom of the housing 101 and connecting it with the second isolation ring group 112, when the measuring device 100 is subjected to external vibration or impact, the elastic element 114 can absorb most of the mechanical energy and buffer the direct impact of these forces on the internal electrodes, so that the electrodes and the isolation ring group are not prone to breakage or relative displacement.

[0057] It should be noted that, Figure 1 The arrows in the diagram are used to indicate the top and bottom directions of housing 101.

[0058] Combination Figure 1As shown, in some embodiments, the inner wall of the housing 101 is provided with a liner 115. The measuring device 100 also includes a top cover base 116, a first lead wire 120, a second lead wire 121, and a connecting wire 122. The top cover base 116 is disposed at the opening 102 of the housing 101 and connected to the liner 115. The top cover base 116 is provided with a first lead tube 117, a second lead tube 118, and a third lead tube 119. One end of the first lead wire 120 is electrically connected to the first collector 105, and the other end of the first lead wire 120 extends through at least the first lead tube 117 to the outside of the receiving cavity 103, for extracting the current signal generated on the first collector 105. One end of the second lead 121 is electrically connected to the second collector 108, and the other end of the second lead 121 extends through at least the second lead tube 118 to the outside of the accommodating cavity 103, for leading out the current signal generated on the second collector 108. One end of the connecting line 122 is electrically connected to the first high-voltage electrode 104 and the second high-voltage electrode 107 respectively through branch lines, and the other end of the connecting line 122 extends through the third lead tube 119 to the outside of the accommodating cavity 103, for introducing external high-voltage power supply to the first high-voltage electrode 104 and the second high-voltage electrode 107.

[0059] The top cover base 116 and the housing 101 together form an airtight, rigid, enclosed space to encapsulate and protect the internal working gas and electrodes. The first lead-out tube 117 provides a path for the first lead-out line 120 to extract the current signal generated on the first collector 105, ensuring that the current signal is not interfered with or crosstalked to other signals during extraction. The second lead-out tube 118 provides a path for the second lead-out line 121 to extract the current signal generated on the second collector 108, ensuring that the current signal is not interfered with or crosstalked to other signals during extraction.

[0060] In practical applications, the top cover base 116 and the housing 101 can be connected by welding to achieve a seal and reduce the exchange of gas with the outside.

[0061] The third lead-out tube 119 provides a lead-out channel for the connecting line 122. The connecting line 122, through the third lead-out tube 119, introduces the external high-voltage power supply to the first high-voltage electrode 104 and the second high-voltage electrode 107 via a branch line, providing operating voltage for the first and second ionization chambers. By setting independent first lead-out tubes 117, second lead-out tubes 118 and third lead-out tubes 119, signal crosstalk can be effectively prevented, and weak current signals can be physically isolated from the high-voltage power supply lines.

[0062] In practical applications, the first high-voltage electrode 104 and the second high-voltage electrode 107 can be shorted by a branch line and then connected to an external high-voltage power supply by a connecting line 122, or they can be connected to an external high-voltage power supply separately. For example, the first annular ionization chamber 106 and the second annular ionization chamber 109 can share a high-voltage power supply and a housing 101 as a signal ground, but the collected signals of the first annular ionization chamber 106 and the second annular ionization chamber 109 are output separately.

[0063] In practical applications, after the first lead-out line 120 and the second lead-out line 121 lead out the current signal from the first collector 105 and the second collector 108 inside the accommodating cavity 103, they can be connected to the measuring instrument end through an extension cable.

[0064] In one possible implementation, the top cover base 116 is provided with an exhaust pipe 124, at least a portion of which extends into the receiving cavity 103 for filling the receiving cavity 103 with working gas and / or evacuating it.

[0065] In practical applications, the working gas enters the accommodating cavity 103 through the exhaust pipe 124, and enters the annular cavity formed by each electrode through the air hole on the clamping member 113, and the working gas flows between each electrode.

[0066] In one possible implementation, the first lead-out tube 117, the second lead-out tube 118, and the third lead-out tube 119 can be made of ceramic to avoid or reduce interference caused by fluctuations in the internal current signal. The first lead-out wire 120, the second lead-out wire 121, and the connecting wire 122 can be made of metal. The connection between the lead-out wires and their corresponding electrodes can be spot welded. The lead-out wires serve as signal paths and are connected to external instruments. The lead-out wires are sealed at the lead-out tubes to achieve the sealing of the accommodating cavity 103.

[0067] Combination Figure 1 and Figure 2 As shown, in some embodiments, the measuring device 100 further includes a plurality of transition rings 123, which are respectively disposed at the connection points of the first lead-out pipe 117, the second lead-out pipe 118 and the third lead-out pipe 119 with the top cover base 116, for buffering thermal stress.

[0068] Specifically, when the measuring device 100 generates heat during operation or when the ambient temperature changes, the expansion / contraction of the metal top cover base 116 is much greater than that of the ceramic lead-out tube. This deformation will generate huge thermal stress at the hard connection between the ceramic and the metal, which can easily lead to cracking of the brittle ceramic and failure of the seal under long-term action. By setting transition rings 123 at the connection between the first lead-out tube 117, the second lead-out tube 118 and the third lead-out tube 119 and the top cover base 116, the thermal stress can be buffered.

[0069] In one possible implementation, the outer surfaces of the lead-out ends of the first lead-out tube 117, the second lead-out tube 118, and the third lead-out tube 119 are sequentially welded with metal layers such as expansion alloy and nickel alloy from the inside to the outside to buffer thermal stress. The end of the first lead-out tube 117, the second lead-out tube 118, and the third lead-out tube 119 furthest from the accommodating cavity 103 is the lead-out end.

[0070] It should be noted that, Figure 2 The arrow F2 in the diagram is used to indicate the direction of the outlet tube from the inside to the outside.

[0071] In one possible implementation, the transition ring 123 can be made of an expanded alloy metal material.

[0072] Combination Figure 1 As shown, in one possible implementation, the measuring device 100 further includes a first lead-out ceramic post 125, a second lead-out ceramic post 126, a third lead-out ceramic post 127, and a fourth lead-out ceramic post 128. The first lead-out ceramic post 125, the second lead-out ceramic post 126, the third lead-out ceramic post 127, and the fourth lead-out ceramic post 128 are correspondingly disposed at the ends of the first collecting electrode 105, the second collecting electrode 108, the first high-voltage electrode 104, and the second high-voltage electrode 107 near the opening 102. The first lead wire 120 also passes through the first lead-out ceramic post 125. The second lead wire 121 also passes through the second lead-out ceramic post 126. The branch lines include a first branch line 129 electrically connected to the first high voltage electrode 105 and a second branch line 130 electrically connected to the second high voltage electrode 107. The end of the first branch line 129 away from the first high voltage electrode 105 passes through the third lead-out ceramic post 127, and the end of the second branch line 130 away from the second high voltage electrode 107 passes through the fourth lead-out ceramic post 128, and both are connected to one end of the connecting line 122.

[0073] By setting the first lead-out ceramic post 125, the second lead-out ceramic post 126, the third lead-out ceramic post 127, and the fourth lead-out ceramic post 128, high-voltage insulation and signal isolation can be achieved, effectively suppressing fluctuations in internal current signals and improving signal stability. The ceramic posts can also provide rigid support and positioning for the electrode leads (such as the first lead-out line 120, the second lead-out line 121, the first branch line 129, and the second branch line 130), maintaining the stability of the lead-out line position and reliable electrical connection even in environments with vibration or temperature changes.

[0074] In practical applications, the first high-voltage electrode 104 and the second high-voltage electrode 107 can be short-circuited by the first branch line 129 and the second branch line 130 respectively, and then connected to an external high-voltage power supply by the connecting line 122, or they can be connected to an external high-voltage power supply separately.

[0075] In one possible implementation, the distance between the second high-voltage electrode 107 and the second collector electrode 108 is 1 mm to 10 mm. The distance between the first collector electrode 105 and the first high-voltage electrode 104 is 1 mm to 10 mm. The distance between the second collector electrode 108 and the first collector electrode 105 is 1 mm to 10 mm.

[0076] By setting the spacing between the electrodes to 1 mm to 10 mm, and combining this with a suitable working gas pressure, complete collection of radiated particle energy can be achieved even with relatively small volumes in the first annular ionization chamber 106 and the second annular ionization chamber 109. The 1 mm to 10 mm electrode spacing results in shorter drift distances for electrons and ions generated by ionization under the influence of the electric field, thus improving charge collection efficiency.

[0077] Combination Figure 7 As shown, this embodiment of the present disclosure provides a control device 800, including a processor 802 and a memory 804 storing program instructions. The processor 802 is configured to execute the following measurement method for a mixed radiation field when executing the program instructions.

[0078] Combination Figure 6 As shown, this application provides a method for measuring mixed radiation fields, comprising the following steps: S11. In response to a measurement request, acquire the first output current of the first collector and the second output current of the second collector.

[0079] Specifically, in response to a measurement request, the processor 802 acquires the first output current of the first collector 105 and the second output current of the second collector. In this embodiment, the first lead 120 leads the current signal of the first collector 105 to an external interface through the first lead tube 117 to acquire the first output current, and the second lead 121 independently leads the current of the second collector 108 to an external interface through the second lead tube 118 to acquire the second output current.

[0080] S12. Obtain the neutron fluence rate calculation model and the gamma ray dose rate calculation model.

[0081] The processor 802 acquires the neutron fluence rate calculation model and the gamma ray dose rate calculation model, enabling high-precision, real-time calculation from the raw signal to the physical quantity.

[0082] S13. Based on the first output current and the second output current, the neutron fluence rate is calculated using the neutron fluence rate calculation model; and based on the second output current, the gamma ray dose rate is calculated using the gamma ray dose rate calculation model.

[0083] The processor 802 calculates the neutron fluence rate based on the first output current using a neutron fluence rate calculation model. It then calculates the gamma ray dose rate based on the second output current using a gamma ray dose rate calculation model.

[0084] In some embodiments, the neutron flux rate calculation model is: Φ=(Ik×I0) / Sn, where k=S γ / S γ0 The gamma-ray dose rate calculation model is: X = I0 / S γ0 In the formula, Φ is the neutron fluence rate, I is the first output current, I0 is the second output current, k is the ratio of the gamma-ray response of the first annular ionization chamber 106 to the second annular ionization chamber 109, Sn is the neutron sensitivity of the first annular ionization chamber 106, and S... γ S represents the gamma-ray sensitivity of the first annular ionization chamber 106. γ0 X represents the gamma ray sensitivity of the second annular ionization chamber 109, and X represents the gamma ray dose rate.

[0085] In this embodiment, the neutron sensitivity of the first annular ionization chamber 106 is calibrated as Sn, and the gamma ray sensitivity is calibrated as S. γ The gamma-ray sensitivity of the second annular ionization chamber 109 was calibrated to S. γ0 Calibration tests of the k-value were performed at different gamma-ray dose rates for subsequent correction. A k-value of 0.5 to 2 can improve the accuracy of the correction, and the compensation ratio can be reduced to below 0.1% through preliminary calibration. The gamma-ray contribution current in the output current of the first annular ionization chamber 106 was obtained as k×I0, and the neutron contribution current in the first annular ionization chamber 106 was obtained as Ik×I0. By calibrating the neutron sensitivity and gamma-ray sensitivity of the first annular ionization chamber 106 and the second annular ionization chamber 109, the neutron fluence rate and gamma-ray dose rate can be accurately distinguished and measured. This method significantly improves the measurement accuracy, especially under rapidly changing neutron fluence rates and complex radiation environments, and can more accurately meet the needs of practical applications. By calibrating the gamma-ray sensitivity in the second annular ionization chamber 109, the influence of gamma rays on the first annular ionization chamber 106 can be effectively compensated, greatly improving the accuracy and reliability of neutron measurement. This compensation method overcomes the shortcomings of existing technologies in accurately compensating for the effects of gamma rays, and significantly improves the measurement accuracy of the first annular ionization chamber 106.

[0086] Example 1 The following example 1 illustrates the application of the measuring device 100 and method for mixed radiation fields in a scenario where gamma ray intensity is high and neutron intensity is low.

[0087] The measuring device 100 can form a measuring system with the signal transmission cable and signal processing equipment.

[0088] The neutron sensitivity of the first annular ionization chamber 106 is calibrated to Sn, and the gamma ray sensitivity is calibrated to S. γ The gamma-ray sensitivity of the second annular ionization chamber 109 was calibrated to S. γ0 S γ0 With S γ They are proportional, that is, S γ =k×S γ0 K-value calibration tests were performed at different gamma ray dose rates for subsequent correction. A k-value of 0.5 to 2 can improve the accuracy of the correction. Through preliminary calibration, the compensation ratio can be reduced to below 0.1%.

[0089] The measuring device 100 can be connected to the signal processing equipment via a signal transmission cable. The signal transmission cable is a shielded coaxial signal cable. The core wires of the transmission cable are respectively connected to the second high voltage electrode 107, the second collecting electrode 108, the first collecting electrode 105, and the first high voltage electrode 104 of the measuring device 100. The cable shielding layer is connected to the housing 101 of the measuring device 100 as the signal ground.

[0090] The signal processing equipment includes a high-voltage power supply module and a current measurement module. The high-voltage power supply module is used to apply a working high voltage to the measuring device 100, and the current measurement module is used to collect the current signal fed back by the measuring device 100. If the measuring devices can share a high-voltage power supply, then it includes at least one high-voltage power supply and two current acquisition modules.

[0091] During neutron-gamma-ray mixed field measurement, the processor 802 pre-acquires the calibrated k value. The measuring device is placed at the measurement position, and the measuring system collects the output current I of the first annular ionization chamber 106 and the output current I0 of the second annular ionization chamber 109, respectively.

[0092] Processor 802 acquires the output current I0 and the gamma ray dose rate calculation model, and uses the gamma sensitivity S calibrated by the second annular ionization chamber 109. γ0 The gamma radiation rate X at the measurement location can be calculated, X = I0 / S γ0 The gamma ray contribution to the output current of the first annular ionization chamber 106 is obtained as k×I0. The neutron contribution to the output current of the first annular ionization chamber 106 is obtained as Ik×I0.

[0093] The processor 802 obtains the current contributed by neutrons in the first annular ionization chamber 106 as Ik×I0 and the neutron fluence calculation model. Based on the neutron sensitivity calibrated in the first annular ionization chamber 106, the neutron fluence at the measurement location can be obtained as Φ=(Ik×I0) / Sn.

[0094] This disclosure also provides a control device 800, the structure of which is as follows: Figure 7 As shown, the system includes a processor 802 and a memory 804, and may also include a communication interface 806 and a bus 808. The processor 802, communication interface 806, and memory 804 can communicate with each other via the bus 808. The communication interface 806 can be used for information transmission. The processor 802 can call logical instructions in the memory 804 to execute the measurement method for mixed radiation fields described in the above embodiment.

[0095] The memory 804, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 802 executes functional applications and data processing by running the program instructions / modules stored in the memory 804, thereby implementing the measurement method for mixed radiation fields in the above-described method embodiments. Therefore, it possesses all the beneficial effects of the above embodiments, which will not be repeated here.

[0096] The memory 804 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 804 may include high-speed random access memory and may also include non-volatile memory.

[0097] This disclosure also provides a computer-readable storage medium including a stored program, wherein the program, when executed, performs the measurement method for a mixed radiation field of any of the foregoing embodiments.

[0098] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0099] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this disclosure includes the entire scope of the claims and all available equivalents of the claims. When used in this application, although the terms “first,” “second,” etc., may be used in this application to describe elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be called a second element without changing the meaning of the description, and likewise, a second element may be called a first element, provided that all occurrences of “first element” are consistently renamed and all occurrences of “second element” are consistently renamed. First and second elements are both elements, but may not be the same element. Moreover, the terminology used in this application is only for describing embodiments and is not intended to limit the claims. As used in the description of the embodiments and claims, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Similarly, the term “and / or” as used herein means including one or more of the associated listed elements and all possible combinations thereof. Additionally, when used in this application, the terms “comprise” and its variations “comprises” and / or “comprising” refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase “comprising an…” does not exclude the presence of additional identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0100] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0101] The methods and products disclosed in the embodiments herein (including but not limited to devices and equipment) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed between each other may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0102] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description; in some cases, there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, or they may be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A measuring device for mixed radiation fields, characterized in that, include: The housing includes a receiving cavity with an opening; A first high-voltage electrode and a first collecting electrode are nested together and disposed within the accommodating cavity of the housing. The first high-voltage electrode and the first collecting electrode define a first annular ionization chamber, which is sensitive to neutrons and gamma rays. A nested second high-voltage electrode and a second collector electrode define a second annular ionization chamber that is sensitive to gamma rays; Along the radial direction of the housing, the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode are nested sequentially from the inside to the outside.

2. The measuring device for a mixed radiation field according to claim 1, characterized in that, The volume of the second annular ionization chamber is 0.5 to 2 times the volume of the first annular ionization chamber.

3. The measuring device for a mixed radiation field according to claim 1, characterized in that, Also includes: An isolation electrode is disposed between the first collector electrode and the second collector electrode, and surrounds the second collector electrode.

4. The measuring device for a mixed radiation field according to claim 1, characterized in that, Also includes: The first isolation ring group is disposed on top of the second high voltage electrode, the second collecting electrode, the first collecting electrode and the first high voltage electrode; The second isolation ring assembly is disposed at the bottom of the second high-voltage electrode, the second collecting electrode, the first collecting electrode, and the first high-voltage electrode.

5. The measuring device for a mixed radiation field according to claim 4, characterized in that, Also includes: A clamping element is disposed inside the housing and near the opening, and the clamping element abuts against the inner wall of the housing; The first isolation ring assembly is disposed on the clamping member, and the second isolation ring assembly is disposed on the side of the housing away from the opening.

6. The measuring device for a mixed radiation field according to claim 5, characterized in that, Also includes: Multiple elastic elements are respectively disposed inside the housing and located on the side of the second isolation ring group away from the opening. One end of each elastic element is connected to the side of the second isolation ring group opposite to the first isolation ring group for shock absorption.

7. The measuring device for a mixed radiation field according to claim 1, characterized in that, The inner wall of the housing is provided with a liner, and the measuring device further includes: A top cover base is disposed at the opening of the housing and connected to the liner. The top cover base is provided with a first outlet pipe, a second outlet pipe and a third outlet pipe. The first lead wire has one end electrically connected to the first collector electrode, and the other end extends through at least the first lead tube to the outside of the accommodating cavity, for leading out the current signal generated on the first collector electrode; The second lead wire has one end electrically connected to the second collector electrode, and the other end extends through at least the second lead tube to the outside of the accommodating cavity, for leading out the current signal generated on the second collector electrode; The connecting wire has one end electrically connected to the first high-voltage electrode and the second high-voltage electrode via branch wires, and the other end extends through the third lead tube to the outside of the accommodating cavity, for introducing external high-voltage power to the first high-voltage electrode and the second high-voltage electrode.

8. The measuring device for a mixed radiation field according to claim 7, characterized in that, Also includes: Multiple transition rings are respectively disposed at the connection points of the first lead-out pipe, the second lead-out pipe, and the third lead-out pipe with the top cover base to buffer thermal stress.

9. A method for measuring a mixed radiation field, comprising measuring neutron fluence and gamma ray dose rate using a measuring apparatus for a mixed radiation field as described in any one of claims 1 to 8, characterized in that, The method for measuring mixed radiation fields includes the following steps: In response to a measurement request, the first output current of the first collector and the second output current of the second collector are acquired. Obtain the neutron fluence rate calculation model and the gamma ray dose rate calculation model; The neutron flux rate is calculated using the neutron flux rate calculation model based on the first output current and the second output current; and the gamma ray dose rate is calculated using the gamma ray dose rate calculation model based on the second output current.

10. The method for measuring a mixed radiation field according to claim 9, characterized in that, The neutron flux rate calculation model is: Φ=(Ik×I0) / Sn, where k=S γ / S γ0 The gamma ray dose rate calculation model is: X = I0 / S γ0 ; In the formula, Φ is the neutron fluence rate, I is the first output current, I0 is the second output current, k is the ratio of the gamma-ray response of the first annular ionization chamber to the second annular ionization chamber, Sn is the neutron sensitivity of the first annular ionization chamber, and S... γ S represents the gamma-ray sensitivity of the first annular ionization chamber. γ0 denoted as Gamma ray sensitivity of the second annular ionization chamber, and X as gamma ray dose rate.

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