Neutron energy spectrum resolving method, system and equipment of single-ball neutron spectrometer and medium

Abstract

Compared with the prior art, the invention discloses a single-ball neutron spectrometer device, which is characterized in that firstly, counting values of a plurality of detectors at different depths in a single-ball neutron spectrometer are obtained through one-time measurement, and the counting values of the plurality of detectors at the same depth are averaged to obtain a counting average value of each depth; the method comprises the following steps: acquiring count values of a plurality of thermal neutron detectors at different depths in a single-sphere neutron spectrometer, averaging the count values of the same depth to obtain a count average value of each depth, and then establishing a response matrix of direction averaging through Monte Carlo simulation; and finally, taking a preset energy spectrum as an initial value, and carrying out fitting solution on the counting average value by adopting an iterative calculation method based on a least square criterion, thereby stably outputting the neutron energy spectrum under the constraint of counting input and a response matrix, reducing the influence of counting random fluctuation on a solution result, and improving the stability and credibility of energy spectrum solution.

Description

Technical Field

[0001] This invention relates to the field of neutron energy spectrum measurement, specifically to a neutron energy spectrum calculation method for a single-sphere neutron spectrometer, a neutron energy spectrum calculation system for a single-sphere neutron spectrometer, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Neutron energy spectrum is an important physical quantity characterizing the energy distribution of a neutron field, widely used in scenarios such as radiation protection evaluation of nuclear facilities, shielding design verification, source term identification, and dose assessment. A single-sphere neutron spectrometer, by placing multiple thermal neutron detectors at different depths inside a spherical moderator, utilizes the different moderation and trapping characteristics of the moderator for neutrons of different energies, causing the responses of detectors at each depth to incident neutrons to differ. This allows the neutron energy spectrum to be obtained through inversion of multi-channel count information. In existing technologies, the measurement results of a single-sphere neutron spectrometer are typically represented as count values ​​or count rates from multiple detectors, requiring further spectral analysis to obtain a neutron energy spectrum suitable for engineering analysis. Therefore, spectral analysis algorithms and software implementation are indispensable key components in the application chain of a single-sphere neutron spectrometer.

[0003] However, existing single-sphere neutron spectrometer spectral interpretation techniques still face many unresolved issues in practical engineering applications, especially in terms of the stability of energy spectrum calculations, the reliability of results, and the ability to characterize complex neutron fields.

[0004] First, existing technologies for converting detector count information from different depths into neutron spectra generally suffer from unstable solutions and significant fluctuations in results. On one hand, neutron spectrum inversion involves a typical set of underdetermined equations, which inevitably exhibit ill-conditioned nature due to measurement errors. Furthermore, the response of detector counts to energy distribution is coupled, and statistical fluctuations and background interference are unavoidable in actual measurements, making the inversion process highly sensitive to input errors and amplifying the resulting errors. On the other hand, existing technologies often fail to establish a unified spectral analysis logic adapted to single-sphere, multi-depth structures. This lack of consistent constraints in input organization, response modeling, and iterative solving of detector count data from different depths easily leads to significant differences in spectral analysis results under different measurement conditions and insufficient consistency in repeated measurements. Moreover, the spectral analysis relies on detector response data, but inconsistencies in the acquisition methods, incident condition assumptions, and matching methods with measured counts across different implementation paths can lead to systematic deviations between the response matrix and the measured data, affecting the reliability and stability of the neutron spectrum output. The aforementioned issues directly limit the usability of single-sphere neutron spectrometers in long-term monitoring of nuclear facilities or rapid measurements in multiple scenarios, representing a core deficiency that urgently needs to be addressed in existing technologies.

[0005] Secondly, existing technologies lack sufficient dimensions for characterizing complex neutron fields, making it difficult to obtain richer directional feature information from single-sphere measurements. Most existing single-sphere neutron spectrometers only focus on the inversion of the energy spectrum, ignoring neutron direction information. However, in practical applications, neutron fields are often not ideally incident from a single direction. For example, there may be multiple source terms, multi-directional superposition due to reflection and scattering, or non-uniform spatial distribution. Simply outputting the neutron energy spectrum is insufficient to meet the needs of source term discrimination, field intensity spatial distribution analysis, and identification of neutron field characteristics in the environment. Since personal dose is closely related to neutron direction, ignoring neutron direction information will lead to inaccurate estimation of personal neutron dose for workers: for example, simply assuming normal neutron incidence will result in overly conservative personal dose estimation. Due to the lack of a direction inversion mechanism that works in conjunction with energy spectrum calculation, existing technologies struggle to derive the angle between the neutron incident direction and the reference axis while simultaneously performing energy spectrum calculation. They also struggle to decompose the incident neutron field into multiple orthogonal directional components and provide the corresponding directional component energy spectra. Consequently, in scenarios with multiple source terms or non-single incident directions, the measurement results are insufficient in information and difficult to interpret, failing to provide more refined support for subsequent engineering decisions.

[0006] Finally, existing technologies still have shortcomings in terms of software-based processes and automated computation. Single-sphere neutron spectrometer spectral analysis typically involves multiple stages, including response data retrieval, initial spectrum setup, iterative solving, and result output. Without a clear and unified software logic architecture, problems such as reliance on human experience, inconsistent settings by different operators, and untraceable computational processes can easily arise, affecting the repeatability and consistency of the analysis results. Especially in applications requiring periodic or real-time analysis, the lack of a stable, programmatic implementation solution that can run on electronic devices or general-purpose computing platforms hinders automated output and standardized deployment, further limiting the widespread application of single-sphere neutron spectrometer spectral analysis technology in engineering fields. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a neutron energy spectrum calculation method, a neutron energy spectrum calculation system, electronic equipment, and computer-readable storage medium for a single-sphere neutron spectrometer that can achieve stable and reliable calculation under the constraints of multi-depth detector counting data and response matrix.

[0008] To solve the above-mentioned technical problems, the technical method adopted by the present invention is as follows: The present invention discloses a method for calculating the neutron energy spectrum of a single-sphere neutron spectrometer, comprising the following steps: S1. Obtain the count values ​​of multiple detectors located at different depths in the single-sphere neutron spectrometer through a single measurement, and average the count values ​​of multiple detectors at the same depth to obtain the average count value at each depth; S2. Through Monte Carlo simulation, the response function of the detector to neutrons of different energies under different incident directions is calculated. Combined with weighted averaging, the direction-averaged neutron response function is given, and the response matrix is ​​established. S3. Based on the least squares criterion, using the preset energy spectrum as the initial value, the average count value of each depth is fitted and solved by the iterative calculation method to obtain the neutron energy spectrum of the measured neutrons and output it.

[0009] Furthermore, it also includes a neutron incident direction derivation step Sa4, which is used to derive the angle between the neutron incident direction and the selected reference axis. Step Sa4 includes: Sa41. Determining the count input for direction derivation based on the average count value of each depth obtained in step S1; Sa42. Calculating the theoretical count corresponding to different candidate incident angles based on the detector response to different incident angles obtained by Monte Carlo calculation, and combining it with the neutron energy spectrum obtained in step S3, and comparing it with the count input to determine the candidate incident angle that matches the count input; Sa43. Outputting the determined candidate incident angle as the angle between the neutron incident direction and the reference axis.

[0010] Furthermore, when the incident direction is not singular and there are multiple neutron source terms, the method further includes a neutron fluence orthogonal component inversion step Sb4. Step Sb4 is used to perform neutron fluence orthogonal component inversion, and step Sb4 includes: Sb41. Taking three mutually orthogonal reference axes, the incident neutron is represented as components along six directions: x, negative x, y, negative y, z, and negative z; Sb42. Based on the detector response to neutrons in different incident directions obtained by Monte Carlo calculation, and combined with the detector count value and the preset energy spectrum, a solution relationship is established between the detector count value and the neutron energy spectrum along the six directions; Sb43. Based on the iterative spectrum solving algorithm, the neutron energy spectrum along the six directions is solved and output in the same iterative solution process; wherein, the neutron fluence orthogonal component inversion is applicable to the case where the incident direction is not singular and there are multiple neutron source terms.

[0011] Furthermore, the direction-averaged response matrix is ​​obtained by: selecting multiple representative incident directions within a 4π solid angle range, and calculating the detector's response to neutrons of different energies under each incident direction based on Monte Carlo simulation; calculating the weight corresponding to each incident direction based on the characteristic that the incident directions are randomly selected with equal probability within a 4π solid angle range; and calculating the weighted average of the responses corresponding to the multiple incident directions according to the given weights to obtain the direction-averaged response matrix.

[0012] Furthermore, the detectors are uniformly arranged at multiple depth positions inside the spherical moderating body; detectors are arranged at distances of 2cm, 4cm, 6cm, and 8cm from the center of the sphere, and the same number of detectors are arranged in each of the 2cm, 4cm, 6cm, and 8cm depth layers, distributed along mutually orthogonal x, y, and z axes.

[0013] Furthermore, the iterative calculation step is based on the least squares criterion, and it iterates with a preset energy spectrum as the initial value. In each iteration, the estimated value of the neutron energy spectrum is updated according to the detector count and its response function until the preset number of iterations or convergence condition is reached.

[0014] Furthermore, in the iterative calculation, a weighting factor is calculated based on the response value of each detector to neutrons of different energies and the measurement error of the detector count, and a weighted least squares iterative calculation is performed based on the weighting factor.

[0015] The present invention also discloses a neutron energy spectrum calculation system for a single-sphere neutron spectrometer, used to implement any of the above-described neutron energy spectrum calculation methods, the system comprising a detection system, an electronics system, and a processing system; The detection system includes a single spherical moderator and multiple thermal neutron detectors arranged at various depths within the moderator to obtain corresponding detector signals; the electronics system is used to convert the detector signals into counting data from the thermal neutron detectors; the spectral decomposition system is used to receive the counting data and call the response matrix and the preset energy spectrum to perform iterative calculations to output the neutron energy spectrum.

[0016] The present invention also discloses an electronic device, including a memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed on the processor, the electronic device is capable of executing any of the single-sphere neutron spectrometer neutron energy spectrum calculation methods described above.

[0017] The present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, includes instructions for implementing any of the above-described neutron energy spectrum calculation methods.

[0018] Beneficial effects: 1. Compared with the prior art, the present invention obtains the count values ​​of multiple thermal neutron detectors at different depths in a single-sphere neutron spectrometer in step S1, and averages the count values ​​at the same depth to obtain the average count value at each depth. Combined with step S2, a response matrix is ​​established by using the response function obtained in advance through Monte Carlo simulation. Then, in step S3, the average count value is fitted and solved using a preset energy spectrum as the initial value and an iterative calculation method based on the least squares criterion. Thus, under the constraints of the count input and the response matrix, the neutron energy spectrum is stably output, which can reduce the impact of random fluctuations in the count on the solution results and improve the stability and reliability of the energy spectrum solution.

[0019] 2. From the overall perspective, this invention, based on the completion of neutron energy spectrum calculation, further utilizes the detector's response information to neutrons incident at different energies and angles to derive the neutron incident direction. By calculating theoretical counts for candidate incident angles and matching them with measured counts, the angle between the incident direction and the reference axis is determined. Simultaneously, the incident neutron can be decomposed into components along six directions: x, negative x, y, negative y, z, and negative z, and the neutron energy spectrum in all six directions can be solved simultaneously in the same iterative solution process. This expands the measurement results from a single energy spectrum to an information output that simultaneously includes directional features and multi-directional component features, making it particularly suitable for scenarios where the incident direction is not singular and there are multiple neutron source terms, thereby significantly enhancing the characterization capability of complex neutron fields.

[0020] 3. This invention solidifies the pre-construction of the response function, the iterative solution mechanism using the preset energy spectrum as the initial value, and the inversion process of the direction and orthogonal components into program logic that can be executed on the spectral interpretation system, electronic equipment, or computer-readable storage medium. This enables the neutron energy spectrum and its extended information to be automatically calculated and output after receiving the counting data, reducing the impact of human intervention and subjective selection on the results, and improving the repeatability, consistency, and engineering deployment convenience of the measurement process. Attached Figure Description

[0021] Figure 1 This is a block diagram of the spectrum interpretation operation logic of the single-sphere neutron spectrometer in this invention; Figure 2 This refers to the file reference and generation logic of the single-sphere neutron spectrometer decoding software in this invention; Figure 3 This describes the workflow of the single-sphere neutron spectrometer interpretation software in this invention. Figure 4 This is a flowchart of the neutron incident angle direction inversion algorithm in this invention; Figure 5 This is a flowchart of the inversion calculation of neutron fluence orthogonal components in this invention. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 This embodiment provides a method for calculating the neutron energy spectrum of a single-sphere neutron spectrometer. Its purpose is to obtain the average count value at each depth in a single measurement, call a pre-obtained response matrix, and execute an iterative spectral analysis algorithm using a preset energy spectrum as the initial value, thereby outputting the neutron energy spectrum. Specifically, it includes the following steps: Step S1. Obtaining the average count: The single-sphere neutron spectrometer obtains the count values ​​from multiple thermal neutron detectors located at different depths through a single measurement. The average count values ​​from multiple thermal neutron detectors at the same depth are then averaged to obtain the average count for each depth. The average count is used as the observation input for the iterative spectrum resolution algorithm.

[0024] Step S2. Response Matrix Establishment: Before measurement, Monte Carlo simulation is used to pre-calculate the response function of the thermal neutron detector to neutrons of different energies, and the response matrix is ​​established accordingly. Re ik This is used to describe the correspondence between the average count at each depth and the neutron energy spectrum.

[0025] Step S3. Iterative spectral analysis algorithm for solution and output: using a preset energy spectrum As initial values, an iterative spectrum-solving algorithm based on the least squares criterion is used to fit and solve the count average. In each iteration, the current neutron energy spectrum estimate is mapped to the count calculation value using the response matrix, and the neutron energy spectrum estimate is updated based on the deviation between the count calculation value and the count average. The iteration automatically terminates after reaching the set number of iterations, and the neutron energy spectrum is output.

[0026] The principle of neutron spectrum interpretation is based on the fact that the neutron moderation materials surrounding detectors at different locations vary, leading to differences in their responses to the neutron energy spectrum of the measured environment. Multiple detectors measure simultaneously, and the relative proportion of counts from each detector reflects the energy distribution of the measured neutron field. This can be combined with neutron spectrum interpretation algorithms to obtain the neutron energy spectrum.

[0027] Preferably, the response matrix is ​​a direction-averaged response matrix. Specifically, multiple representative incident directions are selected within a 4π solid angle range, and the detector's response to neutrons of different energies under each incident direction is calculated based on Monte Carlo simulation. Given that the incident directions are randomly selected with equal probability within a 4π solid angle range, the weights corresponding to each incident direction are calculated. According to the given weights, the weighted average of the responses corresponding to the multiple incident directions is calculated to obtain the direction-averaged response matrix. .

[0028] Assuming the single-sphere neutron spectrometer contains a total of n The detectors at various depths are intended to acquire energy spectra including... m There are 1 energy point, and the mathematical expression for the spectral interpretation process is: ; In the formula, Indicates the first k The average count of all detectors at this depth was obtained experimentally. The response matrix representing the direction average; This represents the measured neutron energy spectrum, which is the quantity to be determined.

[0029] Preferably, the direction-averaged response matrix is ​​obtained by: selecting multiple representative incident directions within a 4π solid angle range, and calculating the detector's response to neutrons of different energies under each incident direction based on Monte Carlo simulation; calculating the weights corresponding to each incident direction based on the characteristic that the incident directions are randomly selected with equal probability within a 4π solid angle range; and calculating the weighted average of the responses corresponding to multiple incident directions according to the given weights to obtain the direction-averaged response matrix.

[0030] In a mathematical sense, neutron spectrum interpretation is equivalent to solving a system of equations, according to n Solving the system of equations m One unknown quantity. Generally, the number of energy points in the energy spectrum that need to be obtained. m Greater than the detector depth number inside a single-sphere neutron spectrometer n Therefore, this problem is an indeterminate equation, and an analytical solution cannot be obtained; only an approximate solution can be obtained.

[0031] Example 2 This embodiment, based on Embodiment 1, presents a detection system arrangement for averaging grouped multi-depth counting inputs and average count values, while providing a geometric model for establishing the response matrix in Monte Carlo simulation.

[0032] The moderator is a polyethylene sphere with a diameter of 30 cm. The thermal neutron detector is... 6 The LiF-coated SiC semiconductor detector has a neutron-sensitive region of 5×5×0.03mm. 3 .

[0033] Thermal neutron detectors were deployed at four depths within the moderator body: 2 cm, 4 cm, 6 cm, and 8 cm. Here, depth refers to the radial distance from the surface of the moderator sphere towards its center; therefore, the corresponding radial distances to the detectors are 13 cm, 11 cm, 9 cm, and 7 cm, respectively.

[0034] Six thermal neutron detectors were deployed at depths of 2 cm and 4 cm, and 6 cm and 8 cm, for a total of 24 thermal neutron detectors. The count values ​​of the detectors at the same depth were averaged to obtain the average count value for that depth. The coordinates of each detector are shown in the table below: The electronics system is used to discriminate and amplify the electronic pulse signals output by the detectors, converting them into detector counts. These detector counts reflect the measured neutron energy information and serve as the input data for spectral analysis. To avoid unnecessary association with other technical solutions, this specification does not elaborate on the electronic details.

[0035] Example 3 Based on Example 1, this embodiment explains the relationship between the average count, the response matrix, and the neutron energy spectrum from a mathematical modeling perspective, and further optimizes the implementation method and weight factor setting of the iterative spectrum solving algorithm so that the algorithm can be directly implemented.

[0036] Preferably, the preset energy spectrum is used as the initial value for the iterative spectral resolution algorithm. The preset energy spectrum can provide the shape and peak positions of the energy spectrum based on a reasonable estimate of the physical properties of the neutron field before measurement, serving as the initial input.

[0037] The iterative spectrum solving algorithm terminates when a set number of iterations is reached. After reaching the set number of iterations, it automatically ends and outputs the neutron energy spectrum.

[0038] The formula for the neutron energy spectrum iteration process is: The weighting factor is: ; In the formula Indicates the first k The average count of all detectors at a given depth; Indicates the first k The average count of all detectors at a certain depth for an energy of The neutron response is obtained in advance through methods such as Monte Carlo calculations; This indicates the measured neutron energy spectrum; denoted as measurement error; J represents the number of iterations.

[0039] Example 4 This embodiment provides an implementation of an iterative spectrum resolution algorithm, focusing on using a preset energy spectrum as the initial value and introducing a weighting factor to achieve stable iteration under the weighted least squares principle, thereby further optimizing the data organization and workflow of the spectrum resolution software.

[0040] like Figure 2 As shown, the files required for the single-sphere neutron spectrometer's interpretation software to run include the preset spectrum file (default), detector count (measurement), detector directional average response (response), and neutron energy spectrum (flu). Additionally, the settings file (set) and dose conversion coefficient (doseCoefficient) need to be calculated.

[0041] Among them, preset energy spectrum data is used to provide preset energy spectrum; count data is used to provide detector count value and average count value obtained from a single measurement; response matrix data is used to provide directional average response matrix obtained in advance by Monte Carlo simulation; calculation setting parameters are used to provide settings such as the number of iterations; and dose conversion coefficient data is used to realize dose-related conversion when needed.

[0042] The spectral analysis software executes an iterative spectral analysis algorithm to output neutron energy spectrum results. Preferably, the neutron energy spectrum results can also be combined with dose conversion coefficient data to output ambient dose equivalents or corresponding dose-related results.

[0043] like Figure 3 As shown, after the spectral analysis software starts and completes the connection configuration, it enters the measurement mode selection. Before the measurement begins, the iteration count setting can be updated. The spectral analysis software provides three time measurement modes: 1. Single-shot mode: After starting the measurement, it continues to measure until the set measurement time ends or a stop command is received, acquires the count data and calculates the average count, executes the iterative spectrum decomposition algorithm, and outputs and displays the neutron energy spectrum results.

[0044] 2. Accumulation Mode: The user sets a time interval N. The software reads and accumulates the count data in a loop at time interval N, calculates the average count based on the accumulated count, executes an iterative spectrum decomposition algorithm, and periodically outputs the neutron energy spectrum results until a stop command is received.

[0045] 3. Timed Mode: The user sets a time interval N. The software reads the count data within that time interval in a loop, calculates the average count value, executes an iterative spectrum analysis algorithm, and periodically outputs the neutron energy spectrum results until a stop command is received.

[0046] Preferably, the single spectral analysis calculation time does not exceed 1 minute, thereby enabling real-time online measurement of the neutron energy spectrum.

[0047] Example 5 This embodiment, based on Embodiment 1, provides a method for further deriving the angle between the neutron incident direction and the reference axis after obtaining the neutron energy spectrum. This direction inversion is based on the neutron energy spectrum calculation results of Embodiment 1, and uses the neutron energy spectrum and the detector angle response to constrain the incident angle, thereby avoiding the instability caused by directly inferring the direction based solely on the difference in counts.

[0048] like Figure 4 As shown, the inputs for direction inversion include the average count, the neutron energy spectrum, and the detector's response data to different incident angles. It should be noted that the direction-averaged response matrix used for neutron energy spectrum calculation in Example 1 can be obtained by weighted averaging of the angle responses used in this example.

[0049] First, the average count obtained in Example 1 is used as the observation input for direction inversion.

[0050] Secondly, using the neutron energy spectrum output from Example 1 as a known prior, and combining it with the detector's response data to different incident angles, the corresponding theoretical count averages are calculated for multiple candidate incident angles, thus establishing a correspondence between the candidate incident angles and the theoretical count averages. Then, the theoretical count averages are matched with the measured count averages to determine the candidate incident angle with the highest consistency with the measured count averages. Finally, the determined candidate incident angle is output as the angle between the neutron incident direction and the reference axis, thereby obtaining the neutron incident direction.

[0051] It should be noted that this embodiment is applicable to situations where the neutron field has a relatively well-defined main incident direction. In this case, by constraining the average count value through the neutron energy spectrum and angular response, a stable angle output can be achieved, and the direction result and the energy spectrum result can be physically consistent with each other.

[0052] When the incident direction is not singular and there are multiple neutron source terms, outputting only a single angle is often insufficient to characterize the true neutron field. A further preferred approach is to represent the incident neutron as a superposition of six orthogonal reference direction components, and simultaneously solve for the energy spectrum in all six directions, thus more comprehensively reflecting the multi-directional superposition neutron field. Specifically, after outputting the neutron energy spectrum, if it is necessary to further characterize the directional features of the neutron field, the neutron incident angle direction inversion can be performed based on the neutron energy spectrum, or the neutron fluence orthogonal component inversion can be performed when the incident direction is not singular to obtain the six-directional energy spectrum result.

[0053] like Figure 5 As shown, the inputs for orthogonal component inversion include the average count, a preset energy spectrum, and detector response data for neutrons with different energies and incident directions. First, three mutually orthogonal reference axes are chosen, and the incident neutron is represented as a superposition of components along six directions: x, -x, y, -y, z, and -z. Second, based on the six-directional response matrices obtained from the Monte Carlo simulation, a solution relationship is established between the average count and the neutron energy spectra in the six directions. Then, using the preset energy spectrum as the initial value, an iterative spectral solving algorithm is employed to simultaneously solve for the neutron energy spectra in all six directions during the same iterative solution process, outputting the six-directional energy spectrum results.

[0054] In summary, the neutron incident angle direction inversion method is suitable for scenarios with a dominant incident direction, outputting angle and direction information. The neutron fluence orthogonal component inversion method is suitable for scenarios with multiple sources or multiple directions, outputting a six-directional energy spectrum. The two methods are complementary and mutually corroborative: when a certain directional component is significant in the six-directional energy spectrum, this significant direction aligns with the directional trend of the neutron incident angle direction inversion output, allowing for mutual verification; when no obvious dominant direction exists in the six-directional energy spectrum, it indicates that the neutron field may be composed of multiple superimposed directional components. In this case, the neutron fluence orthogonal component inversion method can more accurately represent the characteristics of the true neutron field and explain the instability or non-uniqueness that may occur with a single angle output.

[0055] Example 6 Based on the above embodiments, this embodiment provides a systematic and programmed implementation of the neutron energy spectrum calculation method for a single-sphere neutron spectrometer.

[0056] A neutron energy spectrum calculation system for a single-sphere neutron spectrometer includes a detection system, an electronics system, and a spectrum resolution system.

[0057] The detection system includes a spherical moderator and multiple thermal neutron detectors arranged at different depths to obtain detector signals.

[0058] The electronic system is used to convert detector signals into counting data.

[0059] The spectrum decomposition system is used to calculate the average count based on the count data, and calls the response matrix and preset energy spectrum to execute an iterative spectrum decomposition algorithm to output the neutron energy spectrum. It can also perform directional inversion or orthogonal component inversion to output extended results as needed.

[0060] This embodiment also provides an electronic device, including a memory and at least one processor. The memory stores a computer program. When the processor executes the computer program, it causes the electronic device to perform the above-described neutron energy spectrum calculation method, and optionally performs direction inversion and orthogonal component inversion.

[0061] This embodiment also provides a computer-readable storage medium storing a computer program. When the processor executes the computer program, it implements the above-described neutron energy spectrum calculation method and optionally implements direction inversion and orthogonal component inversion.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating the neutron energy spectrum of a single-sphere neutron spectrometer, characterized in that, Includes the following steps: S1. Obtain the count values ​​of multiple detectors located at different depths in the single-sphere neutron spectrometer through a single measurement, and average the count values ​​of multiple detectors at the same depth to obtain the average count value at each depth; S2. Through Monte Carlo simulation, the response function of the detector to neutrons of different energies is obtained in advance, and the response to different incident directions is averaged in the direction to establish the averaged response matrix. S3. Based on the least squares criterion, using the preset energy spectrum as the initial value, the average count value of each depth is fitted and solved by the iterative calculation method to obtain the neutron energy spectrum of the measured neutrons and output it.

2. The neutron energy spectrum calculation method according to claim 1, characterized in that, It also includes a neutron incident direction derivation step Sa4. Step Sa4 is used to derive the angle between the neutron incident direction and the selected reference axis, and step Sa4 includes: Sa41. Determining the count input for direction derivation based on the average count values ​​at each depth obtained in step S1; Sa42. Calculating the theoretical counts corresponding to different candidate incident angles based on the detector response to different incident angles obtained through Monte Carlo calculations, and combining this with the neutron energy spectrum obtained in step S3, and comparing it with the count input to determine the candidate incident angle matching the count input; Sa43. Outputting the determined candidate incident angle as the angle between the neutron incident direction and the reference axis.

3. The neutron energy spectrum calculation method according to claim 1 or 2, characterized in that, When the incident direction is not singular and there are multiple neutron source terms, the method further includes a neutron fluence orthogonal component inversion step Sb4. Step Sb4 is used to perform neutron fluence orthogonal component inversion, and step Sb4 includes: Sb41. Taking three mutually orthogonal reference axes, the incident neutron is represented as components along six directions: x, negative x, y, negative y, z, and negative z; Sb42. Based on the detector response to neutrons in different incident directions obtained by Monte Carlo calculation, and combined with the detector count value and the preset energy spectrum, the solution relationship between the detector count value and the neutron energy spectrum along the six directions is established; Sb43. Based on the iterative spectrum solving algorithm, the neutron energy spectrum along the six directions is solved and output in the same iterative solution process; wherein, the neutron fluence orthogonal component inversion is applicable to the case where the incident direction is not singular and there are multiple neutron source terms.

4. The neutron energy spectrum calculation method for a single-sphere neutron spectrometer according to claim 1, characterized in that, The direction-averaged response matrix is ​​obtained by selecting multiple representative incident directions within a 4π solid angle range, calculating the detector's response to neutrons of different energies under each incident direction based on Monte Carlo simulation, and calculating the weights corresponding to each incident direction. According to the given weights, the weighted average of the responses corresponding to the multiple incident directions is calculated to obtain the direction-averaged response matrix.

5. The neutron energy spectrum calculation method for a single-sphere neutron spectrometer according to claim 1, characterized in that, The detectors are uniformly arranged at multiple depths inside the spherical moderating body; detectors are arranged at distances of 2cm, 4cm, 6cm, and 8cm from the center of the sphere, and the same number of detectors are arranged in each of the 2cm and 4cm, 6cm and 8cm depth layers, distributed along mutually orthogonal x, y, and z axes.

6. The neutron energy spectrum calculation method for a single-sphere neutron spectrometer according to claim 1, characterized in that, The iterative calculation step is based on the least squares criterion, and it iterates with a preset energy spectrum as the initial value. In each iteration, the estimated value of the neutron energy spectrum is updated according to the detector count and its response function until the preset number of iterations or the convergence condition is reached.

7. The neutron energy spectrum calculation method for a single-sphere neutron spectrometer according to claim 6, characterized in that, In the iterative calculation, a weighting factor is calculated based on the response value of each detector to neutrons of different energies and the measurement error of the detector count, and a weighted least squares iterative calculation is performed based on the weighting factor.

8. A neutron energy spectrum calculation system for a single-sphere neutron spectrometer, used to implement the neutron energy spectrum calculation method according to any one of claims 1-7, characterized in that, The system includes a detection system, an electronics system, and a processing system; The detection system includes a single spherical moderator and multiple thermal neutron detectors arranged at various depths within the moderator to obtain corresponding detector signals; the electronics system is used to convert the detector signals into counting data from the thermal neutron detectors; the spectral decomposition system is used to receive the counting data and call the response matrix and the preset energy spectrum to perform iterative calculations to output the neutron energy spectrum.

9. An electronic device, characterized in that, The electronic device includes a memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed on the processor, the electronic device is capable of performing the single-sphere neutron spectrometer neutron energy spectrum calculation method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, includes instructions for implementing any of the neutron energy spectrum calculation methods described in claims 1-7.

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