A method and system for measuring neutron spectra

Abstract

The present application relates to a kind of neutron energy spectrum measurement method and measurement system, wherein the measurement method includes: obtaining the neutron signal obtained by detecting incident neutron beam with detector, detector includes multiple;After processing, neutron signal obtains processing signal;Based on processing signal, the neutron counting rate of each detector is obtained;Set the initial neutron counting rate of the jth energy interval in incident neutron beam as the initial neutron counting rate is substituted into formula and iteratively calculated, when the absolute value of the difference of with is less than the first threshold value of pre-set, it is the neutron counting rate of the jth energy interval in incident neutron beam;The neutron counting rate corresponding to the n energy intervals corresponding to the incident neutron beam of each detector is calculated in turn, and the neutron energy spectrum of incident neutron beam is obtained.The measurement method of the present application is simple in measurement process, and high in accuracy.

Description

Technical Field

[0001] This invention relates to the field of neutron energy spectrum measurement technology, and in particular to a neutron energy spectrum measurement method and measurement system. Background Technology

[0002] Currently, the most widely used methods for measuring the neutron energy spectrum of BNCT (Boron Neutron Capture Therapy) radiation fields are the multi-foil activation method and the multi-sphere spectrometer method. However, both of these methods have complex operating procedures, require a long time for irradiation, measurement, and analysis, and generally have low measurement accuracy. The multi-sphere spectrometer method requires multiple measurements and is easily affected by external conditions. These problems urgently need to be solved. Summary of the Invention

[0003] This invention discloses a neutron energy spectrum measurement method and system, aiming to solve the technical problems existing in the prior art.

[0004] The present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a method for measuring neutron energy spectrum, comprising:

[0006] The detectors are used to detect neutron signals from the incident neutron beam. The detectors include multiple detectors, which are arranged sequentially along the direction of neutron motion and numbered 1-S. The incident neutron beam includes n energy ranges, where n is a positive integer.

[0007] The neutron signal is processed to obtain a processed signal;

[0008] The neutron count rate of each detector is obtained based on the processed signal;

[0009] The initial neutron count rate of the j-th energy range in the incident neutron beam is set to...

[0010] Substitute the initial neutron count rate into the formula Perform iterative calculations when and When the absolute value of the difference is less than a preset first threshold, That is, the neutron count rate in the j-th energy range of the incident neutron beam. Let be the neutron count rate of the j-th neutron energy range in the incident neutron beam during the k-th iteration. This is the correction factor for the k-th iteration;

[0011] The neutron count rate corresponding to the n energy ranges in the incident neutron beam corresponding to each detector is calculated sequentially to obtain the neutron energy spectrum of the incident neutron beam.

[0012] In the neutron energy spectrum measurement method of the present invention, the correction factor in, To contribute weight, R sj δ represents the response of the detector numbered S to the j-th neutron energy range in the incident neutron beam. S N is the standard deviation of the neutron count rate for the n incident neutron beam energy ranges corresponding to the detector numbered S. S Let S be the count rate of the detector for the j-th neutron energy range in the incident neutron beam.

[0013] In the neutron energy spectrum measurement method of the present invention, the response can be obtained by the following formula:

[0014] R Sj =∫φ(E)nVσ(E)dE;

[0015] Among them, R Sj It is the response of the detector numbered S when the energy of the incident neutron beam is E in the energy range;

[0016] φ(E) is the neutron flux with energy E, expressed in cm⁻¹. -2 ;

[0017] n is the amount of LiO2·2SiO2(Ce) in the detector. 6 Li atomic number density, in cm⁻¹ -3 ;

[0018] V is the volume of LiO2·2SiO2(Ce), in cm³. 3 ;

[0019] σ(E) is 6 Li(n,α)T reaction cross-sectional area, in cm² 2 .

[0020] In the neutron energy spectrum measurement method of the present invention, the step of processing the neutron signals to obtain processed signals includes: shaping the neutron signals into multiple unipolar Gaussian waveforms; and denoising the unipolar Gaussian waveforms to obtain processed signals.

[0021] In the neutron energy spectrum measurement method of the present invention, the step of denoising each of the unipolar Gaussian waveforms to obtain a denoised signal is performed by a comparator; the comparator removes signals below a second threshold from the unipolar Gaussian waveforms to obtain the denoised signal.

[0022] In the neutron energy spectrum measurement method of the present invention, the step of obtaining multiple neutron count rates based on the processed signal includes:

[0023] Each of the processed signals is converted into a single-directional square wave signal recognizable by the FPGA, and the neutron count rate is obtained by counting each of the square wave signals through the parallel pulse counting module of the FPGA.

[0024] In a second aspect, the present invention also provides a neutron energy spectrum measurement system, comprising a moderator, multiple detectors, multiple preamplifiers, a signal processing module, and a host computer; the detectors and the preamplifiers are configured in a one-to-one correspondence, and the detectors are electrically connected to the preamplifiers; the multiple preamplifiers are all electrically connected to the signal processing module; the signal processing module is used to process the neutron signals detected by the detectors to obtain a neutron count rate; the host computer is electrically connected to the signal processing module and is used to receive the neutron count rate data and execute any of the above-described measurement methods to obtain a neutron energy spectrum.

[0025] In the measurement system of the present invention, the moderating body includes a housing and a columnar moderating body; the columnar moderating body is disposed within the housing and includes multiple columnar sections; except for the end face of the columnar section adjacent to the neutron inlet on the housing, the end faces of the remaining columnar sections have receiving recesses for accommodating detectors, and the thickness of each columnar section is the same or different; the receiving recesses are arranged sequentially along the direction from approaching to moving away from the neutron inlet; the inlet is positioned directly opposite the receiving recesses.

[0026] In the measurement system of the present invention, the columnar moderating body has a cylindrical structure with a length of 30-40cm and a diameter of 10-20cm.

[0027] In the measurement system of the present invention, the length of the columnar moderating body is 35cm and the diameter is 20cm.

[0028] In the measurement system of the present invention, along the direction from near the inlet to away from the inlet, the distance between each of the receiving recesses and the end face of the columnar moderating body is 0.2cm to 24cm; or 0.2cm to 20cm.

[0029] In the measurement system of the present invention, the detector and the preamplifier are an integrated structure.

[0030] In the measurement system of the present invention, the signal processing module includes multiple amplification and shaping modules and a multi-channel counting module; the amplification and shaping modules are configured one-to-one with the preamplifier and are electrically connected to the preamplifier; the multi-channel counting module includes multiple counting channels, which are configured one-to-one with the amplification and shaping modules, and are used to process the shaped signals of the amplification and shaping modules to obtain the neutron count rate.

[0031] The measurement system of the present invention also includes an analysis module; the analysis module is electrically connected to the amplification and shaping module and is used to observe the waveform of the signal output by the detector.

[0032] The technical solution adopted in this invention can achieve the following beneficial effects:

[0033] This invention primarily provides a neutron energy spectrum measurement method. Based on the simultaneous detection of an incident neutron beam by multiple detectors, it can simultaneously acquire neutron energy spectra in different energy ranges of the incident neutron beam, thereby increasing the detection energy range, simplifying the measurement process, avoiding harm to operators caused by changing the moderator, and improving detection accuracy due to the larger detection energy range. Furthermore, by using a counting contribution weight function to obtain the neutron energy spectrum, it avoids the problem that the neutron energy spectrum cannot be accurately solved analytically when using the response matrix to calculate the neutron energy spectrum, resulting in a more accurate neutron energy spectrum. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 This is a schematic diagram of the structure of a neutron energy spectrum measurement method according to the present invention;

[0036] Figure 2 This is a schematic diagram of the measurement system of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the moderator of the present invention;

[0038] Figure 4 This is a cross-sectional view of the moderating agent of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Moderator; 11. Shell; 111. Neutron inlet; 12. Columnar moderator; 121. Column section; 1211. Receiving recess; 2. Detector; 3. Preamplifier; 4. Signal processing module; 41. Amplification and shaping module; 42. Multi-channel counting module; 5. Host computer; 6. Analysis module. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a magnetic connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0043] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] To address the problems existing in the prior art, this application provides a neutron energy spectrum measurement method and measurement system.

[0045] like Figure 1 As shown, a neutron energy spectrum measurement method includes:

[0046] The detectors obtain neutron signals from the incident neutron beam. There are multiple detectors, which are arranged sequentially along the direction of neutron motion and numbered 1-S. The incident neutron beam includes n energy ranges, that is, the incident neutron beam is divided into multiple energy ranges.

[0047] After processing, the neutron signal is obtained as a processed signal;

[0048] The neutron count rate of each detector is obtained based on the processed signal. When the measurement is performed according to a single energy range, the neutron count rate obtained is the neutron count rate of the corresponding single range. When the measurement is performed on all ranges, the result is the response function of the corresponding detector. The response functions of multiple detectors constitute the response spectrum. The detection of the incident neutron beam by each individual detector is no different from that of existing detectors.

[0049] The initial neutron count rate for the j-th energy range in the incident neutron beam is set to...

[0050] Substitute the initial neutron count rate into the formula Perform iterative calculations when and When the absolute value of the difference is less than a preset first threshold, That is, the neutron count rate in the j-th energy range of the incident neutron beam. Let be the neutron count rate of the j-th neutron energy range in the incident neutron beam during the k-th iteration. This is the correction factor for the k-th iteration;

[0051] The neutron count rate corresponding to the n energy ranges in the incident neutron beam for each detector is calculated sequentially to obtain the neutron energy spectrum of the incident neutron beam.

[0052] The present invention discloses a neutron energy spectrum measurement method based on the simultaneous detection of an incident neutron beam by multiple detectors. This method can simultaneously acquire neutron energy spectra in different energy ranges of the incident neutron beam, thereby increasing the detection energy range, simplifying the measurement process, avoiding harm to operators caused by changing the moderator, and improving detection accuracy due to the larger detection energy range. Furthermore, the use of a counting contribution weight function to obtain the neutron energy spectrum avoids the problem of not being able to accurately solve the neutron energy spectrum using analytical methods when calculating the neutron energy spectrum using the response matrix, resulting in a more accurate neutron energy spectrum.

[0053] In some preferred embodiments, the correction factor in, To contribute weight, R sj For the detector numbered S, δ represents the response of the detector to the j-th neutron energy range in the incident neutron beam (this value is pre-calculated). S Let N be the standard deviation of the neutron count rate for the n incident neutron beam energy ranges corresponding to detector S. S Let S be the count rate of the detector with the number S for the j-th neutron energy range in the incident neutron beam; the count rate of the n neutron energy ranges detected by the detector with the number S is the response function; the response functions obtained by the S detectors form the response spectrum.

[0054] In some preferred embodiments, the response can be obtained by the following formula:

[0055] R Sj =∫φ(E)nVσ(E)dE;

[0056] Among them, R Sj It is the response of detector S when the energy of the incident neutron beam is E;

[0057] φ(E) is the neutron flux with energy E, expressed in cm⁻¹. -2 ;

[0058] n represents the amount of LiO2·2SiO2(Ce) in the detector. 6 Li atomic number density, in cm⁻¹ -3 ;

[0059] V is the volume of LiO2·2SiO2(Ce), in cm³. 3 ;

[0060] σ(E) is 6 Li(n,α)T reaction cross-sectional area, in cm² 2 .

[0061] In some preferred embodiments, the process of processing each neutron signal to obtain a processed signal includes: shaping each neutron signal into multiple unipolar Gaussian waveforms; denoising each unipolar Gaussian waveform to obtain a processed signal; thereby further improving the signal-to-noise ratio.

[0062] In some preferred embodiments, the step of denoising each unipolar Gaussian waveform to obtain a denoised signal is performed by a comparator; the comparator removes signals below a second threshold from the unipolar Gaussian waveform to obtain the denoised signal.

[0063] In some preferred embodiments, the neutron signal is amplified and split into two paths. One path processes the neutron signals to obtain multiple neutron count rate steps, while the other path transmits the original signal waveform from the analyzer to a host computer. This host computer can then observe the waveform in real time to determine the signal accumulation state and the detector's operating status, ensuring the normal operation of the entire detection system.

[0064] In some preferred embodiments, the step of obtaining multiple neutron count rates based on the processed signals includes: converting each processed signal into a single-directional square wave signal recognizable by the FPGA (Field Programmable Gate Array), and counting each square wave signal separately using the parallel pulse counting module of the FPGA to obtain the neutron count rate.

[0065] Example 2

[0066] This embodiment provides a neutron energy spectrum measurement system, such as Figure 2 As shown, the system includes a moderator 1, multiple detectors 2, multiple preamplifiers 3, a signal processing module 4, and a host computer 5. Detectors 2 and preamplifiers 3 are configured in a one-to-one correspondence, and detectors 2 are electrically connected to preamplifiers 3. Multiple preamplifiers 3 are all electrically connected to signal processing module 4. Signal processing module 4 is used to process the neutron signal detected by detectors 2 to obtain the neutron count rate. Host computer 5 is electrically connected to signal processing module 4 and is used to receive neutron count rate data and execute the measurement method of embodiment 1 to obtain the neutron energy spectrum.

[0067] The present invention discloses a neutron energy spectrum measurement system, which is based on the simultaneous detection of an incident neutron beam by multiple detectors 2. It can simultaneously acquire the neutron energy spectrum of the incident neutron beam in different energy ranges, thereby increasing the detection energy range, simplifying the measurement process, avoiding harm to operators caused by changing the moderator, and improving detection accuracy due to the larger detection energy range. It also enables online measurement.

[0068] In some preferred embodiments, such as Figure 3 and 4 As shown, the modulator 1 includes a housing 11 and a columnar modulator 12. The columnar modulator 12 is disposed inside the housing 11 and includes multiple column segments 121, that is, the columnar modulator 12 is divided along a cross section perpendicular to the axis. Except for the end face of the column segment 121 adjacent to the neutron inlet 111 on the housing 11, the end face of each other column segment 121 has a receiving recess 1211 for accommodating the detector, that is, the end face near the neutron inlet 111 does not have a receiving recess 1211. The thickness of each column segment 121 may be the same or different. The receiving recesses 1211 are arranged sequentially along the direction from near to far from the neutron inlet 111. The inlet 111 is positioned directly opposite the receiving recess 1211. Based on the use of a cylindrical structure as the moderator, and the cylindrical moderator 12 comprising multiple cylindrical sections 121, with receiving recesses 1211 on each section 121 to accommodate detectors, multiple detectors can be installed simultaneously. The receiving recesses 1211 are arranged sequentially from near to far from the neutron inlet 111. Therefore, when installing detectors, each detector has a different installation depth, enabling the detection of neutron energy spectra of different energies. This reduces measurement time and simplifies the measurement process by allowing simultaneous measurement of neutron energy spectra of different energies. Furthermore, the ability to obtain neutron energy spectra of different energies simultaneously results in a wider coverage of the neutron detector's response function and more accurate measurement results. Moreover, by forming the cylindrical moderator 12 with multiple cylindrical sections 121 of the same or different thicknesses, the position of each receiving recess 1211 within the cylindrical moderator 12 can be adjusted, adapting to different usage requirements (such as different neutron radiation fields) and facilitating disassembly.

[0069] In some preferred embodiments, the columnar modulator 12 has a cylindrical structure with a length of 30-40 cm and a diameter of 10-20 cm. Within this range, the structure of the modulator 1 is more compact, and the response function of the detector covers the largest possible range. Taking 10 detectors as an example (the specific number is determined according to requirements), the installation depths of each detector are distributed at 0.2 cm, 0.5 cm, 1 cm, 2 cm, 4 cm, 8 cm, 12 cm, 16 cm, 20 cm, and 24 cm, with a beam spot radius of 5 cm. When the diameter of the columnar modulator 12 is 10 cm, and the lengths are set to 30 cm, 35 cm, 40 cm, and 45 cm respectively, the total coverage of the response function of the 10 detectors is not significantly different. Considering the overall size of the equipment, the selected... A length of 30-40cm is considered optimal, as this makes the equipment more compact and easier to operate. When 10 detectors are installed at depths of 0.2cm, 0.5cm, 1cm, 2cm, 4cm, 8cm, 12cm, 16cm, 20cm, and 24cm respectively, with a beam radius of 5cm and a columnar moderator 12 length of 45cm and diameters of 10cm, 12cm, 15cm, 18cm, 20cm, and 25cm respectively, the maximum response value (i.e., the maximum value of the vertical axis of the response matrix) of detectors deeper than the third thermal neutron detector increases significantly with the increase of the diameter of the columnar moderator 12. Furthermore, the energy coverage range between 1×10⁻³MeV and 10MeV is greatly improved. When the diameter of the columnar moderator 12 increases from 20 cm to 25 cm, this trend becomes negligible; therefore, when the length of the columnar moderator 12 is 30-40 cm and the diameter is 10-20 cm, it can simultaneously possess a large energy coverage range and a maximum response value, and the structure of the moderator 1 is more compact; based on the thermal neutrons used in the realization, ~2×10⁻⁶... 10 Therefore, the optimal size can be adjusted for neutron radiation fields with different energy spectrum characteristics.

[0070] Preferably, the columnar moderator 12 has a length of 35 cm and a diameter of 20 cm; in this case, the response function covers the largest range, and the shielding of backscattered neutrons and compactness are better.

[0071] In some preferred embodiments, along the direction from near the inlet 111 to away from the inlet 111, the distances of each receiving recess 1211 (or the end face of each column 121 near the neutron inlet 111) from the end face of the columnar moderator 12 near the neutron inlet 111 are successively distributed in the range of 0.2cm to 24cm (e.g., depths successively of 0.2cm, 0.5cm, 1cm, 2cm, 4cm, 8cm, 12cm, 16cm, 20cm, and 24cm, Example 1); or 0.2cm. Within a range of m to 20cm (e.g., depths of 0.2cm, 0.5cm, 1cm, 2cm, 3cm, 5cm, 8cm, 12cm, 16cm, and 20cm, Example 2); preferably, the distances from each receiving recess 1211 to the end face of the columnar moderating body 12 are 0.2cm, 0.5cm, 1cm, 2cm, 4cm, 8cm, 12cm, 16cm, 20cm, and 24cm, respectively; in this case, the total energy spectrum coverage of the detector is larger; especially in 1×10 -3 MeV ~ 1×10 -1 MeV energy region (ultrathermal neutron to fast neutron energy region).

[0072] In some preferred embodiments, the detector 2 and the preamplifier 3 are integrated into one structure. Based on the principle of one detector 2 corresponding to one preamplifier 3, since the signal amplitude generated by the thermal neutron detector 2 itself is weak, if the detector 2 is simply placed in the moderator 1 and connected to the amplifier outside the moderator 1 through the signal line, the signal amplitude will be further lost during the transmission of the signal line. This reduces the amplitude ratio of the neutron signal to the electronic noise, and the signal-to-noise ratio after the neutron signal and electronic noise are amplified together by the preamplifier 3 is small. However, by welding the detector 2 and the preamplifier 3 together, the signal reduction during the transmission process is avoided, and the signal is directly amplified, thus improving the signal-to-noise ratio.

[0073] In some preferred embodiments, the signal processing module 4 includes multiple amplification and shaping modules 41 and a multi-channel counting module 42. The amplification and shaping modules 41 are configured one-to-one with the preamplifier 3 and are electrically connected to the preamplifier 3, used to amplify and shape the output signal of the preamplifier 3. The multi-channel counting module 42 includes multiple counting channels, each corresponding to one of the amplification and shaping modules 41, used to process the shaped signal from the amplification and shaping modules 41 to obtain the neutron count rate. The multi-channel counting module 42 is an FPGA multi-channel counting module (existing multi-channel technology components can be used, such as model XC7A100T-FGG484-2). Specifically, both the amplification and shaping modules 41 and the preamplifier 3 can be existing devices. The amplification and shaping module 41 shapes the amplified signal output from the preamplifier 3 into multiple unipolar Gaussian waveforms. Noise is removed from each unipolar Gaussian waveform to obtain the processed signal, thereby further improving the signal-to-noise ratio. The step of denoising each unipolar Gaussian waveform to obtain a denoised signal is performed by a comparator; the comparator removes signals in the unipolar Gaussian waveform that are below the second threshold (the specific value can be selected according to the working conditions) to obtain the denoised signal.

[0074] Preferably, multiple amplification and shaping modules 41 and multi-channel counting modules 42 are integrated on a single signal processing circuit board and protected and shielded by a metal casing to simultaneously process multiple (all detector) neutron signals.

[0075] In some preferred embodiments, an analysis module 6 is also included; the analysis module 6 is electrically connected to the amplification and shaping module 41 and is used to observe the waveform of the signal output by the detector, and can also observe the signal accumulation; specifically, the analysis module 6 can be an AD9235.

[0076] In some preferred embodiments, each preamplifier 3 is externally connected to a signal line and a power line, and a ground line is connected in series, i.e., 2S+1 lines. These lines are used to power the detector 2 and transmit the signals output by the preamplifier 3 to the various amplification and shaping modules 41 in the signal processing section. To avoid external noise interference during transmission, all power lines and ground lines are soldered to a multi-pin connector, and all signal lines are soldered to another multi-pin connector. The two connectors are fixed to the metal casing of the slowing agent 1. Similarly, the signal lines of each amplification and shaping module 41 are soldered to the same multi-pin connector, and the power supply system lines of the signal processing module 4 are soldered to another multi-pin connector. The two connectors are fixed to the metal casing of the signal processing module 4. Finally, two well-shielded cables are used to connect to the corresponding connectors of the probe and the signal processing section, respectively, to realize communication between the probe and the signal processing module.

[0077] In some preferred embodiments, the spectrum interpretation software in the host computer 5 can be developed using the C language and supports the Windows operating environment. It reads data from the signal processing module 4 via an interface as the software's data file, and includes a pre-calculated response matrix (i.e., a response matrix composed of multiple responses) and preset spectra obtained through various channels. Then, it performs spectrum interpretation calculations using an iterative algorithm based on maximum entropy. The spectrum interpretation software supports changing the measurement period. During runtime, the spectrum interpretation software executes the measurement method described in Embodiment 1 above; alternatively, other existing spectrum interpretation software can also be used.

[0078] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for measuring neutron energy spectrum, characterized in that, include: The detectors are used to detect neutron signals from the incident neutron beam. The detectors include multiple detectors, which are arranged sequentially along the direction of neutron motion and numbered 1-S. The incident neutron beam includes n energy ranges, where n is a positive integer. The neutron signal is processed to obtain a processed signal; The neutron count rate of each detector is obtained based on the processed signal; The initial neutron count rate of the j-th energy range in the incident neutron beam is set to... Substitute the initial neutron count rate into the formula Perform iterative calculations when and When the absolute value of the difference is less than a preset first threshold, That is, the neutron count rate in the j-th energy range of the incident neutron beam. Let be the neutron count rate of the j-th neutron energy range in the incident neutron beam during the k-th iteration. This is the correction factor for the k-th iteration; The neutron count rate corresponding to the n energy ranges in the incident neutron beam corresponding to each detector is calculated sequentially to obtain the neutron energy spectrum of the incident neutron beam.

2. The neutron energy spectrum measurement method according to claim 1, characterized in that, The correction factor in, To contribute weight, R sj δ represents the response of the detector numbered S to the j-th neutron energy range in the incident neutron beam. S N is the standard deviation of the neutron count rate for the n incident neutron beam energy ranges corresponding to the detector numbered S. S Let S be the count rate of the detector for the j-th neutron energy range in the incident neutron beam.

3. The neutron energy spectrum measurement method according to claim 2, characterized in that, The response can be obtained from the following formula: R Sj =∫φ(E)nVσ(E)dE; Among them, R Sj It is the response of the detector numbered S when the energy of the incident neutron beam is E in the energy range; φ(E) is the neutron flux with energy E, expressed in cm⁻¹. -2 ; n is the amount of LiO2·2SiO2(Ce) in the detector. 6 Li atomic number density, in cm⁻¹ -3 ; V is the volume of LiO2·2SiO2(Ce), in cm³. 3 ; σ(E) is 6 Li(n,α)T reaction cross-sectional area, in cm² 2 .

4. The neutron energy spectrum measurement method according to claim 1, characterized in that, The process of processing each of the neutron signals to obtain the processed signal includes: Each of the neutron signals is shaped into multiple unipolar Gaussian waveforms; The unipolar Gaussian waveforms are denoised to obtain the processed signal.

5. The neutron energy spectrum measurement method according to claim 4, characterized in that, The step of denoising each of the unipolar Gaussian waveforms to obtain a denoised signal is performed by a comparator; The comparator removes signals below the second threshold from the unipolar Gaussian waveform to obtain a noise-reduced signal.

6. The neutron energy spectrum measurement method according to claim 1, characterized in that, The step of obtaining multiple neutron count rates based on the processed signal includes: Each of the processed signals is converted into a single-directional square wave signal recognizable by the FPGA, and the neutron count rate is obtained by counting each of the square wave signals through the parallel pulse counting module of the FPGA.

7. A neutron energy spectrum measurement system, characterized in that, It includes a moderator, multiple detectors, multiple preamplifiers, a signal processing module, and a host computer; The detector and the preamplifier are configured in a one-to-one correspondence, and the detector is electrically connected to the preamplifier; Multiple of the aforementioned preamplifiers are electrically connected to the signal processing module; The signal processing module is used to process the neutron signal detected by the detector to obtain the neutron count rate; The host computer is electrically connected to the signal processing module and is used to receive the neutron count rate data and execute the measurement method described in any one of claims 1-6 to obtain the neutron energy spectrum.

8. The measurement system according to claim 7, characterized in that, The moderating body includes a shell and a columnar moderating body; The columnar moderating body is disposed within the housing and includes multiple column sections; Except for the end face of the column adjacent to the neutron inlet on the housing, the end faces of the remaining columns have receiving recesses for accommodating the detector, and the thickness of each column may be the same or different. Each of the aforementioned receiving recesses is arranged sequentially from the direction closest to to the direction furthest from the neutron inlet; The inlet is positioned directly opposite the receiving recess.

9. The measurement system according to claim 8, characterized in that, The columnar moderating body has a cylindrical structure with a length of 30-40cm and a diameter of 10-20cm.

10. The measurement system according to claim 9, characterized in that, The columnar moderating body is 35cm long and 20cm in diameter.

11. The measurement system according to claim 8, characterized in that, Along the direction from near the inlet to far from the inlet, the distance between each of the receiving recesses and the end face of the columnar moderating body is 0.2cm to 24cm; or 0.2cm to 20cm.

12. The measurement system according to claim 11, characterized in that, The detector and the preamplifier are an integrated structure.

13. The measurement system according to claim 11, characterized in that, The signal processing module includes multiple amplification and shaping modules and a multi-channel counting module; The amplification and shaping module is configured in a one-to-one correspondence with the preamplifier and is electrically connected to the preamplifier; The multi-channel counting module includes multiple counting channels, each corresponding to amplification and shaping module, and is used to process the shaping signal of the amplification and shaping module to obtain the neutron count rate.

14. The measurement system according to claim 13, characterized in that, It also includes an analysis module; The analysis module is electrically connected to the amplification and shaping module and is used to observe the waveform of the signal output by the detector.

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