Detector signal processing circuit and detector signal processing method

Abstract

A detector signal processing circuit (100) and a detector signal processing method. The detector signal processing circuit (100) comprises: a detector (10), which is used for generating a detection signal; a pulse mode circuit (20), which is connected to the detector (10), wherein the pulse mode circuit (20) is used for performing pulse shaping on the detection signal, so as to obtain a pulse signal; a high-order mode circuit (30), which comprises a plurality of Campbell modules (31) connected in parallel, wherein input ends of the Campbell modules (31) are connected to the detector (10), and each Campbell module (31) is used for converting the detection signal into a first-order signal; a current mode circuit (40), which is connected to the detector (10), wherein the current mode circuit (40) is used for converting the detection signal into a current signal; and a control module (50), which is respectively connected to the pulse mode circuit (20), the current mode circuit (40), and an output end of each Campbell module (31). The detector signal processing circuit (100) and the detector signal processing method can improve the accuracy of a neutron flux detection result and expand the measurement range of the detector (10).

Description

Detector signal processing circuit and detector signal processing method Technical Field

[0001] This application relates to the field of nuclear technology applications, and in particular to a detector signal processing circuit and a detector signal processing method. Background Technology

[0002] The fission chamber detector is a neutron detector with a wide measurement range. Due to its high gamma-ray coherence capability, it is widely used in neutron measurements in high-gamma-ray environments. The fission chamber detector has three modes: pulse mode, mean square mode, and current mode. The pulse and mean square modes have the ability to suppress gamma-ray noise, while the current mode signal is proportional to the gamma-ray dose. In neutron flux environments where the proportion of gamma rays in the reactor is relatively high, the different degrees of gamma-ray suppression by the three modes lead to significant deviations in measurement results at the same neutron flux level. Therefore, the detector signal processing circuits in related technologies typically can only process the pulse and mean square mode signals of the fission chamber detector, or only the current mode signal, resulting in a narrow measurement range. Summary of the Invention

[0003] This application provides a detector signal processing circuit and a detector signal processing method, which can improve the accuracy of neutron flux detection results and expand the measurement range of the detector.

[0004] In a first aspect, embodiments of this application provide a detector signal processing circuit, characterized in that it includes:

[0005] Detector, the detector being used to generate a detection signal;

[0006] A pulse mode circuit is connected to the detector and is used to perform pulse shaping on the detection signal to obtain a pulse signal.

[0007] A higher-order mode circuit, comprising multiple Campbell modules connected in parallel, wherein the input terminal of each Campbell module is connected to the detector, and the Campbell module is used to convert the detection signal into a first-order signal;

[0008] A current-mode circuit is connected to the detector, and the current module is used to convert the detection signal into a current signal;

[0009] A control module is connected to the output terminals of the pulse-mode circuit, the current-mode circuit, and each of the Campbell modules. The control module is used to determine the higher-order signal of the higher-order mode circuit based on the first-order signal of each Campbell module; when the higher-order signal is greater than the upper limit signal value of a first linear overlap interval, it determines a comparison result between the signal-to-noise ratio in the current signal and a predetermined ratio threshold based on the higher-order signal and the current signal, where the first linear overlap interval is the linear overlap interval between the higher-order signal and the current signal; and when the comparison result indicates that the signal-to-noise ratio in the current signal is greater than or equal to the predetermined ratio threshold, it determines the neutron flux detection result based on the higher-order signal.

[0010] The detector signal processing circuit provided in the first aspect of the embodiments of this application has at least the following beneficial effects: The detector signal processing circuit includes a higher-order mode circuit, which adopts the higher-order Campbell's theorem and includes multiple Campbell modules connected in parallel. Compared with the mean square mode circuit, the higher-order mode circuit has a stronger suppression of gamma rays, and the more order of the higher-order mode circuit, i.e., the more Campbell modules, the stronger the suppression of gamma rays, the stronger the resolution of neutrons, and the more accurate the higher-order signal. In addition, the circuit signal of the current mode circuit is proportional to the gamma dose. In order to reduce the influence of gamma rays, when the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e., the neutron flux is within the measurement interval of the higher-order mode circuit or the current mode, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is greater than or equal to a predetermined ratio threshold, thereby determining that the gamma ray content is high and has a greater impact on the current signal. Therefore, the final output is based on the higher-order signal, and the neutron flux detection result is determined based on the higher-order signal. The detector signal processing circuit of this application embodiment includes a pulse mode circuit, a higher-order mode circuit, and a current mode circuit, which can process signals of three modes simultaneously, expanding the measurement range of the detector. The setting of the higher-order mode circuit and the processing of related signals reduce the influence of gamma rays on neutron flux measurement and improve the accuracy of neutron flux detection results.

[0011] According to some embodiments of this application, it also includes:

[0012] A preamplifier, the input of which is connected to the detector, and the output of which is connected to the input of the pulse mode circuit and the input of each of the Campbell modules.

[0013] According to some embodiments of this application, the Campbell module includes:

[0014] A delay unit, the input of which is connected to the preamplifier;

[0015] A bandpass filter is provided, the input of which is connected to the output of the delay unit. The input of the bandpass filter is also connected to the control module. The delay times of the delay units of the multiple Campbell modules are set in an arithmetic sequence.

[0016] According to some embodiments of this application, the pulse mode circuit includes:

[0017] A multi-stage amplifier, wherein the input terminal of the multi-stage amplifier is connected to the output terminal of the preamplifier;

[0018] A comparator, wherein the first input terminal of the comparator is connected to the multi-stage amplifier, and the second input terminal of the comparator is connected to the first voltage source;

[0019] A pulse shaper, the input of which is connected to the output of the comparator, and the output of which is connected to the control module.

[0020] According to some embodiments of this application, the current-mode circuit includes:

[0021] transformer;

[0022] An oscillation circuit is connected to the input terminal of the transformer;

[0023] A voltage processing circuit, wherein the input terminal of the voltage processing circuit is connected to the first output terminal of the transformer, and the output terminal of the voltage processing circuit is connected to the detector;

[0024] A voltage feedback circuit, comprising an error amplifier, wherein a first input terminal of the error amplifier is connected to the output terminal of the voltage processing circuit, a second output terminal of the error amplifier is connected to a second voltage source, and the output terminal of the error amplifier is connected to the input terminal of the transformer;

[0025] A current sampling circuit is provided, wherein the input terminal of the current sampling circuit is connected to the second output terminal of the transformer, and the output terminal of the current sampling circuit is connected to the control module.

[0026] According to some embodiments of this application, the voltage feedback circuit further includes:

[0027] A voltage sampling circuit, wherein the input terminal of the voltage sampling circuit is connected to the output terminal of the voltage processing circuit, and the output terminal of the voltage sampling circuit is connected to the first input terminal of the error amplifier;

[0028] A Darlington transistor is used, the input of which is connected to the output of the error amplifier, and the output of which is connected to the input of the transformer.

[0029] Secondly, embodiments of this application provide a detector signal processing method applied to a detector signal processing circuit. The detector signal processing circuit includes a detector, a pulse-mode circuit, a higher-order mode circuit, and a current-mode circuit. The higher-order mode circuit includes multiple Campbell modules connected in parallel. Each Campbell module, the pulse-mode circuit, and the higher-order mode circuit are connected to the detector. The method includes:

[0030] Based on the first-order signals of each of the Campbell modules, the higher-order signals of the higher-order mode circuit are determined.

[0031] Determine the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit;

[0032] When the higher-order signal is greater than the upper limit signal value of the first linear overlap block, the comparison result of the signal noise ratio in the current signal and the predetermined ratio threshold is determined based on the higher-order signal and the current signal.

[0033] If the comparison result indicates that the proportion of signal noise in the current signal is greater than or equal to a predetermined proportion threshold, the neutron flux detection result is determined based on the higher-order signal.

[0034] According to some embodiments of this application, determining the comparison result of the signal-to-noise ratio in the current signal with a predetermined ratio threshold based on the higher-order signal and the current signal includes:

[0035] Determine a first difference between the current signal and the higher-order signal;

[0036] Based on the absolute value of the first difference and the ratio of the higher-order signal, the proportion of signal noise in the current signal is determined;

[0037] The signal-to-noise ratio is compared with a predetermined ratio threshold to obtain a comparison result between the signal-to-noise ratio and the predetermined ratio threshold.

[0038] According to some embodiments of this application, after determining the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit, the method further includes:

[0039] When the higher-order signal or the current signal is located in the first linear overlap interval, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is less than a predetermined ratio threshold.

[0040] Determine the second difference between the higher-order signal and the lower limit signal value of the first linear overlap interval;

[0041] Determine the third difference between the upper limit signal value and the lower limit signal value of the first linear overlap interval;

[0042] Based on the second difference and the third difference, a first weight of the current signal and a second weight of the higher-order signal are determined;

[0043] Based on the first weight and the second weight, a first weighted sum of the current signal and the higher-order signal is determined;

[0044] Based on the first weighted sum, the neutron flux detection result is determined.

[0045] According to some embodiments of this application, after determining the higher-order signal of the higher-order mode circuit based on the first-order signal of each of the Campbell modules, the method further includes:

[0046] Determine the second linear overlap interval between the pulse signal and the higher-order signal;

[0047] When the pulse signal or the higher-order signal is located in the second linear overlap interval, a fourth difference between the pulse signal and the lower limit signal value of the second linear overlap interval is determined.

[0048] Determine the fifth difference between the upper limit signal value and the lower limit signal value of the second linear overlap interval;

[0049] Based on the fourth difference and the fifth difference, the third weight of the higher-order signal and the fourth weight of the pulse signal are determined.

[0050] Based on the third weight and the fourth weight, a second weighted sum of the higher-order signal and the pulse signal is determined;

[0051] The neutron flux detection result is determined based on the second weighted sum.

[0052] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0053] The accompanying drawings are used to provide a further understanding of the embodiments of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0054] Figure 1 is a structural block diagram of the detector signal processing circuit provided in an embodiment of this application;

[0055] Figure 2 is a schematic diagram of the first linear overlap interval and the second linear overlap interval provided in the embodiments of this application;

[0056] Figure 3 is a schematic diagram of a preamplifier provided in an embodiment of this application;

[0057] Figure 4 is a schematic diagram of a high-order mode circuit provided in an embodiment of this application;

[0058] Figure 5 is a schematic diagram of a delay unit in a Campbell module provided in an embodiment of this application;

[0059] Figure 6 is a schematic diagram of a bandpass filter in a Campbell module provided in an embodiment of this application;

[0060] Figure 7 is a schematic diagram of a pulse mode circuit provided in an embodiment of this application;

[0061] Figure 8 is a structural block diagram of a current-mode circuit provided in an embodiment of this application;

[0062] Figure 9 is a schematic diagram of a current-mode circuit provided in an embodiment of this application;

[0063] Figure 10 is a flowchart of a detector signal processing method provided in an embodiment of this application;

[0064] Figure 11 is a flowchart of the comparison result of determining the signal-to-noise ratio and the predetermined ratio threshold in step S300 of Figure 10;

[0065] Figure 12 is another flowchart of the detector signal processing method provided in an embodiment of this application;

[0066] Figure 13 is a flowchart of a detector signal processing method provided in an embodiment of this application when the pulse signal or higher-order signal is located in the second linear overlap region. Detailed Implementation

[0067] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the embodiments of this application with unnecessary detail.

[0068] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0069] It should also be understood that references to "one embodiment" or "some embodiments" in the specification of embodiments of this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0070] In the description of this application, terms such as "not less than," "less than," and "exceeding" are understood to exclude the stated number, while terms such as "above," "below," and "within" are understood to include the stated number. The use of terms like "first" and "second" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, the quantity of indicated technical features, or the order of the indicated technical features. It should be understood that directional descriptions, such as "up," "down," "front," "back," "left," and "right," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are solely for the purpose of facilitating and simplifying the description of this application and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0071] The fission chamber detector is a neutron detector with a wide measurement range. Due to its high gamma-ray coherence capability, it is widely used in neutron measurements in high-gamma-ray environments. The fission chamber detector has three modes: pulse mode, mean square mode, and current mode. The pulse and mean square modes have the ability to suppress gamma-ray noise, while the current mode signal is proportional to the gamma-ray dose. In neutron flux environments where the proportion of gamma rays in the reactor is relatively high, the different degrees of gamma-ray suppression by the three modes lead to significant deviations in measurement results at the same neutron flux level. Therefore, the detector signal processing circuits in related technologies typically can only process the pulse and mean square mode signals of the fission chamber detector, or only the current mode signal, resulting in a narrow measurement range.

[0072] Based on this, embodiments of this application provide a detector signal processing circuit and a detector signal processing method. The detector signal processing circuit provided in this application can improve the accuracy of neutron flux detection results and expand the measurement range of the detector.

[0073] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0074] Referring to Figures 1 and 4, this application provides a detector signal processing circuit 100, which includes a detector 10, a pulse mode circuit 20, a high-order mode circuit 30, a current mode circuit 40, and a control module 50.

[0075] Detector 10 is used to generate detection signals.

[0076] The pulse mode circuit 20 is connected to the detector 10. The pulse mode circuit 20 is used to perform pulse shaping on the detection signal to obtain a pulse signal.

[0077] The pulse mode circuit 30 includes multiple Campbell modules 31 connected in parallel. The input terminal of the Campbell module 31 is connected to the detector 10. The Campbell module 31 is used to convert the detection signal into a first-order signal.

[0078] The current-mode circuit 40 is connected to the detector 10, and the current module is used to convert the detection signal into a current signal.

[0079] The control module 50 is connected to the output terminals of the pulse mode circuit 20, the current mode circuit 40, and each Campbell module 31.

[0080] Control module 50 is specifically used for:

[0081] Based on the first-order signals of each Campbell module 31, the higher-order signals of the pulse mode circuit 30 are determined.

[0082] When the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, the signal-to-noise ratio in the current signal is determined based on the higher-order signal and the current signal, and the result of the comparison between the signal-to-noise ratio and the predetermined ratio threshold is determined. The first linear overlap interval is the linear overlap interval between the higher-order signal and the current signal.

[0083] If the comparison result indicates that the proportion of signal noise in the current signal is greater than or equal to a predetermined proportion threshold, the neutron flux detection result is determined based on the higher-order signal.

[0084] It should be noted that detector 10 is specifically a fission chamber detector, which can be used to measure the neutron flux outside the reactor and generate a detection signal. When the neutron flux level is relatively low, the detection signal is a pulsed electrical signal, and the frequency of the pulse is proportional to the neutron flux level. As the neutron flux level increases, the pulsed signals superimpose with each other, and the detection signal becomes a pulsating DC electrical signal with a certain frequency.

[0085] It should be noted that in pulsed mode, the fission chamber detector can detect and count individual neutron events, making it suitable for low neutron flux environments. The advantage of pulsed mode lies in its ability to effectively distinguish and count individual neutron events, thus providing accurate neutron flux measurements. Furthermore, in low neutron flux environments, the control module 50 can only detect the pulse signal output by the pulsed mode circuit 20. The control module 50 performs pulse counting on the pulse signal to perform neutron flux statistics. In low neutron flux environments, the count rate of the detection signal output by the detector 10 is typically less than 10. 5 cps, which means the number of radiation detected per second is less than 10. 5 .

[0086] Referring to Figure 1, the control module 50 is a Field Programmable Gate Array (FPGA). The FPGA can process pulse signals and calculate the count rate by counting the number of pulses per unit time. This count rate is proportional to the neutron flux. In addition, the pulse signal is input to the FPGA through a buffer, which can reduce the occurrence of pulse signal attenuation and distortion, and improve the stability of the detector signal processing circuit 100.

[0087] It should be noted that the pulse-mode circuit 30, i.e., the higher-order Campbell circuit, is implemented based on the higher-order Campbell's theorem. Specifically, the pulse-mode circuit 30 includes multiple Campbell modules 31. The more Campbell modules 31 there are, the higher the order of Campbell's theorem, and the stronger the suppression of gamma noise. The higher-order signal determined based on the first-order signal output by each Campbell module 31 is more accurate.

[0088] The pulse-mode circuit 30 measures neutron flux by analyzing fluctuations in direct current, making it suitable for medium fission ranges, i.e., neutron flux environments. In this case, the count rate is typically 10-1. 5 cps up to 10 10 cps.

[0089] In a neutron flux environment, the control module 50 detects the first-order signal output by the Campbell module 31, and then determines the higher-order signal of the pulse mode circuit 30 based on the first-order signals of each Campbell module 31. The calculation formula for determining the higher-order signal varies depending on the number of Campbell modules 31 in the pulse mode circuit 30. Assuming the sampled voltages, i.e., the first-order signals, of the n Campbell modules 31 in the pulse mode circuit 30 are V1, V2, ..., Vn, the sampled voltages are converted into a variable Yn proportional to the neutron flux according to the following formula:

[0090] Where Yn is a higher-order signal, n represents the number of Campbell modules 31 in the pulse-mode circuit 30, m is a positive integer, indicating that the pulse-mode circuit 30 includes m Campbell modules 31, and j is a positive integer in [1, m-2]. Vi represents the acquisition voltage corresponding to the i-th Campbell module 31 in the pulse-mode circuit 30, i.e., the first-order signal.

[0091] It should be noted that, since the dimensions of the three modes are different, the control module 50 converts the current signal, higher-order signal, and pulse signal into corresponding neutron flux signals for processing. Assuming the current signal is Yi and its corresponding neutron sensitivity is Si, then the neutron flux signal corresponding to the current signal is Fi = Yi * Si. Assuming the pulse signal is Ycps and its corresponding neutron sensitivity is Scps, then the neutron flux signal in pulse mode is Fcps = Ycps * Scps. If the higher-order signal is Yn, its corresponding neutron sensitivity is Fh = Yn * Sh. The comparison between the higher-order signal and the current signal is also based on their corresponding neutron flux signals.

[0092] In addition, when the neutron flux is near the critical value of low neutron flux and medium neutron flux, the control module 50 will detect both pulse signal and high-order signal at the same time. At this time, neutron flux statistics can be performed based on the weight of the overlapping area of ​​the two signals.

[0093] It should be noted that the current mode is primarily used in high fission rate ranges, i.e., high neutron flux environments. The current mode is suitable for situations where frequent pulses cannot be separated, generating a continuous current, thus enabling the measurement of the average DC current from detector 10. However, the current signal of the current mode circuit 40 is proportional to both neutron flux and gamma dose. In high gamma environments, the measurement results determined based on the current mode have significant errors.

[0094] To address this issue, when the higher-order signal exceeds the upper limit of the first linear overlap interval, the signal-to-noise ratio in the current signal is determined based on both the higher-order signal and the current signal. The signal noise in the current signal is caused by gamma rays. Based on this signal-to-noise ratio, the error between the neutron flux determined based on the current signal and the actual neutron flux can be determined. When the signal-to-noise ratio is greater than or equal to a predetermined threshold, the error between the neutron flux determined based on the current signal and the actual neutron flux is significant. Therefore, the higher-order signal is used as the final output signal, and the detection result of the neutron flux is determined based on the higher-order signal.

[0095] The first linear overlap region is the linear overlap region between the higher-order signal and the current signal. There are linear overlap and saturation regions between the higher-order signal and the current signal. Referring to Figure 2, [N] l1 N h1The first linear overlap region is the linear overlap area between the higher-order signal and the current signal. In the first linear overlap region, since the control module 50 detects both the higher-order signal and the current signal simultaneously, it needs to connect the higher-order signal and the current signal. In the saturation region, although both the higher-order signal and the current signal are detected simultaneously, the current signal is usually used as the output signal in order to achieve a smooth transition between the signals.

[0096] However, since the current signal is proportional to the gamma dose, in order to reduce the impact of gamma rays on the accuracy of the detected neutron flux, the detection result of the neutron flux is determined based on the higher-order signal when the higher-order signal is greater than the upper limit signal value of the first linear overlap interval and the signal noise ratio is greater than or equal to a predetermined ratio threshold.

[0097] It should be noted that the predetermined percentage threshold can be set as needed. If the signal-to-noise ratio in the current signal is greater than or equal to the predetermined percentage threshold, the neutron flux measurement result is determined based on the higher-order signal. If the signal-to-noise ratio in the current signal is less than the predetermined percentage threshold, the neutron flux measurement result is determined based on the current signal.

[0098] It should be noted that the detector signal processing circuit 100 provided in this application embodiment is only applicable to fission chamber detectors.

[0099] It should be noted that the detector signal processing circuit 100 includes a pulse mode circuit 30. The pulse mode circuit 30 adopts a higher-order Campbell's theorem and includes multiple Campbell modules 31 connected in parallel. Compared with the mean square mode circuit, the pulse mode circuit 30 has a stronger suppression of gamma rays. Moreover, the higher the order of the pulse mode circuit 30, i.e., the more Campbell modules 31 there are, the stronger the suppression of gamma rays, the stronger the resolution of neutrons, and the more accurate the higher-order signal. In addition, the circuit signal of the current mode circuit 40 is proportional to the gamma dose. To reduce the influence of gamma rays, when the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e., when the neutron flux is within the measurement interval of the pulse mode circuit 30 or the current mode circuit 40, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is greater than or equal to a predetermined ratio threshold. This indicates that the gamma ray content is high and has a greater impact on the current signal. Therefore, the final output is based on the higher-order signal, and the neutron flux detection result is determined based on the higher-order signal. The detector signal processing circuit 100 of this application embodiment includes a pulse mode circuit 20, a pulse mode circuit 30, and a current mode circuit 40, which can process signals in three modes simultaneously, expanding the measurement range of the detector 10. The setting of the pulse mode circuit 30 and the processing of related signals reduce the influence of gamma rays on neutron flux measurement and improve the accuracy of neutron flux detection results.

[0100] In one embodiment, referring to FIG1, the detector signal processing circuit 100 further includes a preamplifier 60, the input terminal of which is connected to the detector 10, and the output terminal of which is connected to the input terminal of the pulse mode circuit 20 and the input terminals of each Campbell module 31.

[0101] It should be noted that the preamplifier 60 is used to amplify the detection signal output by the detector 10, increase the strength of the detection signal, and facilitate the processing of the detection signal by the pulse mode circuit 20 and each Campbell module 31.

[0102] Referring to Figure 3, which is a circuit diagram of the preamplifier 60 provided in this embodiment, the equivalent circuit corresponding to the detector and cable includes a current source Id, an insulation resistance Rd, and a distributed capacitance C0. HV can be considered as the high-voltage power supply of the detector 10, and R1 can be considered as the filter resistor of the detector 10. The high-voltage power supply and the filter resistor of the detector 10 are combined to enable the detector 10 to work normally. In addition, capacitor C1, resistor R2, diode D1, diode D2, amplifier A1, resistor Rf, and capacitor Cf together constitute the circuit of the preamplifier 60. Among them, A1 can be an integrated operational amplifier or a discrete amplifier built with transistors. C1 is a high-voltage capacitor, which is mainly used to isolate high voltage. R2 is the matching resistor of the cable, and its value is usually 50 ohms (Ω). D1 and D2 are used for surge protection to reduce the destructive impact of current surges caused by high voltage changes on amplifier A1. Rf is the amplifier feedback resistor, and Cf is the amplifier feedback capacitor. Therefore, the transfer function of this circuit can be determined as:

[0103] Where H(s) is the transfer function of preamplifier 60, V(s) is the output voltage of preamplifier 60, I(s) is the output current of the amplifier, and s is the independent variable of the Laplace transform, usually expressed as a complex variable. C1 is the value of capacitor C1, C0 is the value of capacitor C0, τ1 is the time constant corresponding to capacitor C1 and resistor R1, and τ1=R1C1, τ f τ is the time constant corresponding to capacitor Cf and resistor Rf, and τ f =R f C f R1 is the value of resistor R1, R f Let Rf be the value of the resistor.

[0104] In one embodiment, referring to FIG4, the Campbell module 31 includes a delay unit and a bandpass filter. The input terminal of the delay unit is connected to the preamplifier 60, the output terminal of the delay unit is connected to the input terminal of the bandpass filter, the input terminal of the bandpass filter is connected to the control module 50, and the delay times corresponding to the delay units of the multiple Campbell modules 31 are set in an arithmetic sequence.

[0105] It should be noted that after the detection signal is amplified by the preamplifier 60, it is processed by multiple Campbell modules 31 of the pulse mode circuit 30. Each Campbell module 31 includes a delay unit and a bandpass filter, and the delay times corresponding to the delay units of the multiple Campbell modules 31 are set in an arithmetic sequence, while the bandpass filters of the multiple Campbell modules 31 are all the same.

[0106] The delay times of multiple delay units form an arithmetic sequence, which can be expressed as Tdn = Td0 + T*n, where Tdn is the delay time of the nth delay unit, and Td0 is the time offset, which is determined by the pulse width output by the preamplifier 60 and is independent of the pulse width of the probe signal. Regardless of the pulse width of the probe signal, the pulse width of the output signal of the preamplifier 60 remains a fixed value. Assuming the pulse width output by the preamplifier 60 is 100 microseconds, then the time offset Td0 is 100 microseconds. T is the delay time difference between two adjacent delay units, which can be set to 1 second. Therefore, the delay times of the n delay units are 101 microseconds, 102 microseconds, ..., 100+n microseconds.

[0107] The delay unit can be configured as a transmission line of arithmetic sequence length or as an all-pass filter. If the delay unit is an all-pass filter, the delay can be set by controlling the phase. The delay unit is configured to facilitate the acquisition of first-order signals corresponding to different Campbell modules 31.

[0108] Referring to Figure 5, the delay unit is configured as a full-pass filter. The input terminal Vin of the delay unit is connected to the preamplifier 60, and the output terminal Vout of the delay unit is connected to the input terminal of the bandpass filter. R37, R38, R39, and C21 together constitute the full-pass filter. The full-pass filter achieves phase adjustment by introducing a phase delay without affecting the frequency characteristics of the signal. Therefore, the delay times of multiple delay units can be set in an arithmetic sequence using a full-pass filter without affecting the signal input to the preamplifier 60.

[0109] The bandpass filter in Campbell module 31 is shown in Figure 6. In the bandpass filter shown in Figure 6, C4, C5, R10, R12, and U12 constitute a second-order active high-pass filter, and R13, R14, C6, C8, and U13 constitute a second-order active low-pass filter. The second-order active high-pass filter and the second-order active low-pass filter together constitute the bandpass filter. To further enhance the clarity and intelligibility of the signal input to the bandpass filter, this embodiment adds a high-pass filter circuit and a first amplifier before the bandpass filter. Referring to Figure 6, Vin represents the probe signal processed by the preamplifier 60 and the delay unit. C12, R21, C3, R11, C7, R15, C17, and R23 constitute a high-pass filter circuit, used to suppress low-frequency noise and enhance high-frequency signals, thereby improving the clarity and intelligibility of the signal. To further enhance the clarity and intelligibility of the probe signal, U10, R6, and R7 constitute an amplifier for positive amplification of Vin. In addition, the embodiments of this application also provide a second amplifier after the bandpass filter for amplifying the first-order signal. U19, R36, and R35 in Figure 6 constitute the second amplifier.

[0110] The delay unit and the bandpass filter form independent channels to measure the detection signal separately and obtain the first-order signal. The control module 50 obtains the higher-order signal based on multiple first-order signals, thereby realizing the application of the higher-order Campbell's theorem. The determination of the higher-order signal can further enhance the suppression of γ-rays and improve the measurement accuracy.

[0111] In one embodiment, referring to FIG1, the pulse mode circuit 20 includes a multistage amplifier, a comparator, and a pulse shaper. The input terminal of the multistage amplifier is connected to the output terminal of the preamplifier 60. The first input terminal of the comparator is connected to the multistage amplifier, and the second input terminal of the comparator is connected to a first voltage source. The input terminal of the pulse shaper is connected to the output terminal of the comparator, and the output terminal of the pulse shaper is connected to the control module 50.

[0112] It should be noted that the multistage amplifier is used to further amplify the signal output from the preamplifier 60 to improve signal strength. The first input of the comparator is connected to the multistage amplifier, and the second input of the comparator is connected to the first voltage source. The comparator compares the pulse signal amplified by the multistage amplifier with the discrimination threshold voltage, i.e., the voltage value of the first voltage source, thereby outputting a standard transistor-transistor logic (TTL) level pulse signal.

[0113] The discrimination threshold voltage can be set as needed, and the value range of the discrimination threshold voltage is usually 0 to 5V.

[0114] Referring to Figure 7, which is a schematic diagram of the pulse mode circuit 20 provided in an embodiment of this application, Vin is the detection signal amplified by the preamplifier 60. U9, R4, and R5 constitute a first-stage amplifier circuit, and U11, R8, and R9 constitute a second-stage amplifier circuit. The first-stage and second-stage amplifier circuits together constitute the multi-stage amplifier in Figure 1. U14 is a comparator that compares the pulse signal amplified by U11 with the discrimination threshold voltage, i.e., the voltage value of the first voltage source, thereby outputting a standard TTL level pulse signal. The pulse shaper includes a monostable logic chip U2A, resistor R34, and capacitor C20. R34 and C20 are used to control the output pulse width of U2A, i.e., the pulse width in the pulse signal. The pulse width is determined based on the product of R34 and C20; the larger the product of R34 and C20, the larger the pulse width. In addition, in order to improve the clarity and intelligibility of the signal input to the bandpass filter, the embodiments of this application provide a high-pass filter circuit before the bandpass filter. C2, R3, C9, R16, C10 and R17 in Figure 7 together constitute the high-pass filter circuit.

[0115] Referring to Figure 1, the control module 50 converts each first-order signal into a digital signal through digital-to-analog conversion, and processes the digital signal through the FPGA.

[0116] In one embodiment, referring to Figures 1 and 8, the current-mode circuit 40 includes a transformer, an oscillation circuit 41, a voltage processing circuit 42, a voltage feedback circuit 43, and a current sampling circuit 44. The oscillation circuit 41 is connected to the input terminal of the transformer. The input terminal of the voltage processing circuit 42 is connected to the first output terminal of the transformer, and the output terminal of the voltage processing circuit 42 is connected to the detector 10. The voltage feedback circuit 43 includes an error amplifier, the first input terminal of which is connected to the output terminal of the voltage processing circuit 42, the second output terminal of which is connected to a second voltage source, and the output terminal of the error amplifier is connected to the input terminal of the transformer. The input terminal of the current sampling circuit 44 is connected to the second output terminal of the transformer, and the output terminal of the current sampling circuit 44 is connected to the control module 50.

[0117] It should be noted that the oscillation circuit 41 is connected to the input terminal of the transformer and is used to generate a continuous oscillation signal. The transformer is used to convert the input oscillation signal into a high-voltage signal, and this high-voltage signal is processed by the voltage processing circuit 42 to provide the operating voltage for the detector 10.

[0118] The voltage feedback circuit 43 includes an error amplifier. The first input terminal of the error amplifier is connected to the output terminal of the voltage processing circuit 42, the second output terminal of the error amplifier is connected to a second voltage source, and the output terminal of the error amplifier is connected to the input terminal of the transformer. The error amplifier compares the output voltage value of the voltage processing circuit 42 with the high-voltage set value, i.e., the output voltage of the second voltage source, and feeds this feedback to the transformer, thereby adjusting the output voltage value of the voltage processing circuit 42 to make it equal to the high-voltage set value.

[0119] The current sampling circuit 44 is connected to the input terminal and the second output terminal of the transformer to sample the current value in the detection signal of the detector 10 and output it to the control module 50, thereby realizing neutron detection under high neutron flux.

[0120] In one embodiment, referring to Figures 1 and 8, the voltage feedback circuit 43 further includes a voltage sampling circuit and a Darlington transistor. The input terminal of the voltage sampling circuit is connected to the output terminal of the voltage processing circuit 42, and the output terminal of the voltage sampling circuit is connected to the first input terminal of the error amplifier. The input terminal of the Darlington transistor is connected to the output terminal of the error amplifier, and the output terminal of the Darlington transistor is connected to the input terminal of the transformer.

[0121] It should be noted that the voltage sampling circuit is used to sample the output voltage of the voltage processing circuit 42 so that the error amplifier can compare the output voltage of the voltage processing circuit 42 with the high voltage set value, i.e., the output voltage of the second voltage source.

[0122] A Darlington transistor is a composite transistor consisting of two or more transistors connected in series, characterized by high current gain and high input impedance. The Darlington transistor operates by connecting two transistors in series, with the collector of the first transistor connected to the base of the second transistor, and the emitter of the first transistor connected to the emitter of the second transistor, thus forming an equivalent new transistor. This configuration allows the current amplified by the first transistor to be further amplified by the second transistor, achieving very high current gain and thus enhancing the output signal of the error amplifier.

[0123] Figure 9 is a schematic diagram of a current-mode circuit 40 provided in an embodiment of this application. Referring to Figures 8 and 9, T1 is a transformer. The voltage processing circuit 42 includes a voltage multiplier circuit and a high-voltage filter circuit. The input terminal of the voltage multiplier circuit is connected to the first output terminal of the transformer, the output terminal of the voltage multiplier circuit is connected to the input terminal of the high-voltage filter circuit, and the output terminal of the high-voltage filter circuit is connected to the detector 10. The voltage multiplier circuit includes D1, C14, D2, and C13 as shown in Figure 9. The voltage multiplier circuit is used to convert the output voltage of the transformer into a higher output voltage. The high-voltage filter circuit includes R18, C16, C15, R19, and R20, which are used to filter out low-frequency noise and enhance the voltage signal, thereby providing a high voltage HV to the detector 10. R26, R27, and U17 in Figure 9 constitute a high-voltage sampling circuit. R26 and R27 are used to perform voltage division sampling on the high voltage HV output by the voltage processing circuit 42. U16, R25, R24, C18, and C19 constitute the error amplifier in the voltage feedback circuit 43. This amplifier compares the high-voltage sampled value with the high-voltage setpoint, thereby using negative feedback to adjust Q3 and Q4 (Darlington transistors) to drive the transformer and convert to a suitable high voltage. R22, R29, R28, D3, U18, D4, R30, R31, R33, R32, and U15 constitute the current sampling circuit 44. The current sampling circuit 44 samples the output voltage of the transformer, thus outputting a voltage V_Iout, which is the voltage corresponding to the output current in the current signal. The oscillation circuit 41 includes transistors and an oscillator. Q1 and Q2 are the transistors in the oscillation circuit 41. U1A, U1B, U1C, U21, R37, R38, C21, and C22 constitute the oscillator, where U1A, U1B, and U1C are Schmitt trigger inverters.

[0124] Referring to Figure 1, in this embodiment of the application, the output voltage V_Iout is converted into a digital signal through a voltage acquisition circuit, and the converted digital signal is processed by an FPGA.

[0125] It should be noted that the detector signal processing circuit 100 in this embodiment includes a pulse mode circuit 30. The pulse mode circuit 30 adopts a higher-order Campbell's theorem and includes multiple Campbell modules 31 connected in parallel. Compared with the mean square mode circuit, the pulse mode circuit 30 has a stronger suppression of gamma rays. The more order of the pulse mode circuit 30, i.e., the more Campbell modules 31, the stronger the suppression of gamma rays, the stronger the resolution of neutrons, and the more accurate the higher-order signal. In addition, the circuit signal of the current mode circuit 40 is proportional to the gamma dose. To reduce the influence of gamma rays, when the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e., when the neutron flux is within the measurement interval of the pulse mode circuit 30 or the current mode, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is greater than or equal to a predetermined ratio threshold. This indicates that the gamma ray content is high and has a greater impact on the current signal. Therefore, the final output is based on the higher-order signal, and the neutron flux detection result is determined based on the higher-order signal. The detector signal processing circuit 100 of this application embodiment includes a pulse mode circuit 20, a pulse mode circuit 30, and a current mode circuit 40, which can process signals in three modes simultaneously, expanding the measurement range of the detector 10. The setting of the pulse mode circuit 30 and the processing of related signals reduce the influence of gamma rays on neutron flux measurement and improve the accuracy of neutron flux detection results.

[0126] In addition, this application embodiment also provides a detector signal processing method. This method is applied to a detector processing circuit 100, which includes a detector 10, a pulse-mode circuit 20, a pulse-mode circuit 30, and a current-mode circuit 40. The pulse-mode circuit 30 includes multiple Campbell modules 31 connected in parallel. Each Campbell module 31, pulse-mode circuit 20, and pulse-mode circuit 30 is connected to the detector 10. The detector signal processing method includes, but is not limited to, the following steps:

[0127] Step S100: Determine the higher-order signals of the higher-order mode circuit based on the first-order signals of each Campbell module.

[0128] Step S200: Determine the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit.

[0129] Step S300: When the higher-order signal is greater than the upper limit signal value of the first linear overlap block, determine the comparison result of the signal noise ratio in the current signal and the predetermined ratio threshold based on the higher-order signal and the current signal.

[0130] Step S400: If the signal-to-noise ratio in the current signal indicated by the comparison result is greater than or equal to a predetermined ratio threshold, determine the neutron flux detection result based on the higher-order signal.

[0131] It should be noted that the first-order signal is the signal obtained by processing the detection signal of each Campbell pair of detector 10.

[0132] The number of Campbell modules 31 in the pulse-mode circuit 30 varies, resulting in different formulas for determining higher-order signals. Assuming the sampled voltages (i.e., first-order signals) of the n Campbell modules 31 in the pulse-mode circuit 30 are V1, V2, ..., Vn, the sampled voltages are converted into a variable Yn proportional to the neutron flux using the following formula:

[0133] Where Yn is a higher-order signal, n represents the number of Campbell modules 31 in the pulse-mode circuit 30, m is a positive integer, indicating that the pulse-mode circuit 30 includes m Campbell modules 31, and j is a positive integer in [1, m-2]. Vi represents the acquisition voltage corresponding to the i-th Campbell module 31 in the pulse-mode circuit 30, i.e., the first-order signal.

[0134] It should be noted that, since the dimensions of the three modes are different, the control module 50 converts the current signal, higher-order signal, and pulse signal into corresponding neutron flux signals for processing. Assuming the current signal is Yi and its corresponding neutron sensitivity is Si, then the neutron flux signal for the current signal is Fi = Yi * Si. Assuming the pulse signal is Ycps and its corresponding neutron sensitivity is Scps, then the neutron flux signal in pulse mode is Fcps = Ycps * Scps. If the higher-order signal is Yn, its corresponding neutron sensitivity is Fh = Yn * Sh. The comparison between the higher-order signal and the current signal is also based on their corresponding neutron flux signals.

[0135] The first linear overlap region is the region where the higher-order signal and the current signal of the current-mode circuit 40 linearly overlap. Furthermore, the determination of the first linear overlap region is also based on the neutron flux signal.

[0136] There is a linear overlap region and a saturation region between higher-order signals and current signals. Referring to Figure 2, [N] l1 N h1 The first linear overlap region is the linear overlap area between the higher-order signal and the current signal. In the first linear overlap region, since the control module 50 detects both the higher-order signal and the current signal simultaneously, it needs to connect the higher-order signal and the current signal. In the saturation region, although both the higher-order signal and the current signal are detected simultaneously, the current signal is usually used as the output signal in order to achieve a smooth transition between the signals.

[0137] It should be noted that the signal-to-noise ratio refers to the proportion of signal noise caused by the gamma signal in the current signal.

[0138] The current mode is primarily used in high fission rate ranges, i.e., high neutron flux environments. It is suitable for situations where frequent pulses cannot be separated, generating a continuous current that allows for the measurement of the average DC current from detector 10. However, the current signal from the current mode circuit 40 is proportional to both neutron flux and gamma dose. In high gamma environments, measurements based on the current mode exhibit significant errors.

[0139] To address this issue, when the higher-order signal exceeds the upper limit of the first linear overlap interval, the signal-to-noise ratio in the current signal is determined based on both the higher-order signal and the current signal. The signal noise in the current signal is caused by gamma rays. Based on this signal-to-noise ratio, the error between the neutron flux determined based on the current signal and the actual neutron flux can be determined. When the signal-to-noise ratio is greater than or equal to a predetermined threshold, the error between the neutron flux determined based on the current signal and the actual neutron flux is significant. Therefore, the higher-order signal is used as the final output signal, and the detection result of the neutron flux is determined based on the higher-order signal.

[0140] It should be noted that the predetermined percentage threshold can be set as needed. If the signal-to-noise ratio in the current signal is greater than or equal to the predetermined percentage threshold, the neutron flux measurement result is determined based on the higher-order signal. If the signal-to-noise ratio in the current signal is less than the predetermined percentage threshold, the neutron flux measurement result is determined based on the current signal.

[0141] It should be noted that the detector signal processing method provided in this application embodiment is only applicable to fission chamber detectors.

[0142] It should be noted that the detector signal processing circuit 100 includes a pulse mode circuit 30. The pulse mode circuit 30 adopts a higher-order Campbell's theorem and includes multiple Campbell modules 31 connected in parallel. Compared with the mean square mode circuit, the pulse mode circuit 30 has a stronger suppression of gamma rays. Moreover, the higher the order of the pulse mode circuit 30, i.e., the more Campbell modules 31 there are, the stronger the suppression of gamma rays, the stronger the resolution of neutrons, and the more accurate the higher-order signal. In addition, the circuit signal of the current mode circuit 40 is proportional to the gamma dose. To reduce the influence of gamma rays, when the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e., when the neutron flux is within the measurement interval of the pulse mode circuit 30 or the current mode, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is greater than or equal to a predetermined ratio threshold. This indicates that the gamma ray content is high and has a greater impact on the current signal. Therefore, the final output is based on the higher-order signal, and the neutron flux detection result is determined based on the higher-order signal. The detector signal processing circuit 100 of this application embodiment includes a pulse mode circuit 20, a pulse mode circuit 30, and a current mode circuit 40, which can process signals in three modes simultaneously, expanding the measurement range of the detector 10. The setting of the pulse mode circuit 30 and the processing of related signals reduce the influence of gamma rays on neutron flux measurement and improve the accuracy of neutron flux detection results.

[0143] In one embodiment, referring to FIG11, step S300 includes, but is not limited to, the following steps:

[0144] Step S310: Determine the first difference between the current signal and the higher-order signal.

[0145] Step S320: Determine the signal-to-noise ratio in the current signal based on the absolute value of the first difference and the ratio of the higher-order signal.

[0146] Step S330: Compare the signal-to-noise ratio with the predetermined ratio threshold to obtain the comparison result of the signal-to-noise ratio and the predetermined ratio threshold.

[0147] It should be noted that the first difference refers to the ratio between the current signal and the higher-order signal. The signal-to-noise ratio in the current signal can be expressed as: Where Fi is the current signal, Fh is the higher-order signal, and Fi-Fh is the first difference between the current signal and the higher-order signal.

[0148] Since the current signal is directly proportional to both neutron flux and gamma dose, under the condition of a constant neutron flux, a higher gamma dose results in a larger current signal, and a larger, positive, first difference between the current signal and higher-order signals. Therefore, the signal-to-noise ratio in the current signal can be determined based on the ratio of the first difference to the higher-order signal. However, to reduce errors, the signal-to-noise ratio in the current signal is usually determined based on the ratio of the absolute value of the first difference to the higher-order signal. Comparing the signal-to-noise ratio with a predetermined threshold yields the comparison result.

[0149] Assuming the predetermined percentage threshold is P1, then when the signal-to-noise ratio is... At that time, the higher-order signal is used as the output signal to determine the neutron flux detection result.

[0150] In one embodiment, referring to FIG12, after step S200, the detector signal processing method further includes:

[0151] Step S510: When the higher-order signal or current signal is located in the first linear overlap interval, based on the higher-order signal and the current signal, determine that the signal noise ratio in the current signal is less than a predetermined ratio threshold.

[0152] Step S520: Determine the second difference between the higher-order signal and the lower limit signal value of the first linear overlap interval.

[0153] Step S530: Determine the third difference between the upper limit signal value and the lower limit signal value of the first linear overlap interval.

[0154] Step S540: Based on the second difference and the third difference, determine the first weight of the current signal and the second weight of the higher-order signal.

[0155] Step S550: Based on the first weight and the second weight, determine the first weighted sum of the current signal and the higher-order signal.

[0156] Step S560: Determine the neutron flux detection result based on the first weighted sum.

[0157] It should be noted that the first linear overlap region is the linear overlap region between the higher-order signal and the current signal. When either the higher-order signal or the current signal is located in the first linear overlap region, both the higher-order signal and the current signal are detected simultaneously. At this time, based on the higher-order signal and the current signal, it can be determined that the signal-to-noise ratio in the current signal is less than a predetermined ratio threshold, that is, the relative error in measuring neutron flux between the current mode and the higher-order mode is small, and the error in gamma-ray noise is small.

[0158] Specifically, assuming the current signal is Fi and the higher-order signal is Fh, then the signal-to-noise ratio is determined. The percentage is less than the predetermined threshold value, which is P1.

[0159] It should be noted that the second difference is the difference between the higher-order signal and the lower limit signal value of the first linear overlap interval, and the third difference is the difference between the upper limit signal value and the lower limit signal value of the first linear overlap interval. Referring to Figure 2, the first linear overlap interval is [Nl1, Nh1]. Then the upper limit signal value of the first linear overlap interval is Nh1, the lower limit signal value is Nl1, the second difference can be expressed as Fh-Nl2, and the third difference can be expressed as Nh1-Nl1.

[0160] After determining the second and third differences, the first weight of the current signal and the second weight of the higher-order signals are determined. The sum of the first and second weights is 1. The first weight of the current signal can be expressed as:

[0161] Where w1 is the first weight and Fh is the higher-order signal. Then, the second weight of the higher-order signal can be expressed as:

[0162] Among them, w2 is the second weight.

[0163] It should be noted that the first and second weights can be set arbitrarily, as long as the second weight of the higher-order signal is smaller and the first weight of the current signal is larger as the higher-order signal gets closer to the upper limit of the first linear overlap interval.

[0164] It should be noted that after determining the first and second weights, a first weighted sum of the current signal and the higher-order signal is calculated, and then the neutron flux detection result is determined based on the first weighted sum. The first weighted sum can be expressed as w2*Fh+w1*Fi, where w1 is the first weight, w2 is the second weight, Fi is the current signal, and Fh is the higher-order signal.

[0165] It should be noted that when the higher-order signal or current signal is located in the first linear overlap region, the larger the higher-order signal, the smaller its second weight in the output signal, and the larger the first weight of the current signal. Since the higher-order signal is closer to the upper limit signal value of the first linear overlap region and closer to the measurement range corresponding to the current signal, the value determined based on the first weight and the second weight is more accurate, which improves the accuracy of the neutron flux measurement results and realizes a smooth connection between the higher-order mode and the current mode.

[0166] In one embodiment, referring to FIG13, after step S100, the detector signal processing method further includes:

[0167] Step S610: Determine the second linear overlap interval between the pulse signal and the higher-order signal.

[0168] Step S620: When the pulse signal or higher-order signal is located in the second linear overlap interval, determine the fourth difference between the pulse signal and the lower limit signal value of the second linear overlap interval.

[0169] Step S630: Determine the fifth difference between the upper limit signal value and the lower limit signal value of the second linear overlap interval.

[0170] Step S640: Based on the fourth and fifth differences, determine the third weight of the higher-order signal and the fourth weight of the pulse signal.

[0171] Step S650: Based on the third and fourth weights, determine the second weighted sum of the higher-order signal and the pulse signal.

[0172] Step S660: Determine the neutron flux detection result based on the second weighted sum.

[0173] It should be noted that the pulse mode is typically used for measuring low neutron flux levels, while the higher-order mode is used for measuring neutron flux levels. When the neutron flux is near the critical value between low and neutron flux, both pulse and higher-order signals can be detected simultaneously. This critical value between low and neutron flux levels can be considered the second linear overlap region.

[0174] The second linear overlap region is the linear overlap area between the pulse signal and the higher-order signal. Within this region, both the pulse signal and the higher-order signal are detected simultaneously. There are linear overlap and saturation regions between the pulse signal and the higher-order signal. Referring to Figure 2, [Nl2, Nh2] represents the linear overlap region between the pulse signal and the higher-order signal, i.e., the second linear overlap region. In the second linear overlap region, since both the higher-order signal and the pulse signal are detected simultaneously, a transition between them is necessary. In the saturation region, although both the pulse signal and the higher-order signal are detected simultaneously, the higher-order signal is typically used as the output signal to achieve a smooth transition between the signals.

[0175] When determining that a pulse signal or higher-order signal is located within the second linear overlap interval, a fourth difference is determined between the pulse signal and the lower limit signal value of the second linear overlap interval, and a fifth difference is determined between the upper limit signal value and the lower limit signal value of the second linear overlap interval. Assuming the second linear overlap interval is [Nl2, Nh2] and the pulse signal is Fcps, then the fourth difference is Fcps-Nl2, and the fifth difference is Nh2-Nl2.

[0176] After determining the fourth and fifth differences, the third weight of the higher-order signal and the fourth weight of the pulse signal are determined. The sum of the third and fourth weights is 1. The third weight of the higher-order signal can be expressed as:

[0177] Where w3 is the third weight and Fcps is the pulse signal. Then the fourth weight of the pulse signal can be expressed as:

[0178] Among them, w4 is the fourth weight.

[0179] It should be noted that the third and fourth weights can be set arbitrarily, as long as the pulse signal is closer to the upper limit of the second linear overlap interval, the fourth weight corresponding to the pulse signal is smaller, and the third weight of the higher-order signal is larger.

[0180] It should be noted that after determining the third and fourth weights, a second weighted sum of the higher-order signal and the pulse signal is calculated, and then the neutron flux detection result is determined based on the second weighted sum. The second weighted sum can be expressed as w4*Fcps+w3*Fh, where w3 is the third weight, w4 is the fourth weight, Fh is the higher-order signal, and Fcps is the pulse signal.

[0181] It should be noted that when the pulse signal or higher-order signal is located within the second linear overlap region, the larger the pulse signal, the smaller its fourth weight in the output signal, and the larger the third weight of the higher-order signal. Since the pulse signal is closer to the upper limit signal value of the second linear overlap region and closer to the measurement range corresponding to the higher-order signal, the values ​​determined based on the third and fourth weights are more accurate, improving the accuracy of neutron flux measurement results and achieving a smooth transition between pulse mode and higher-order mode.

[0182] It should be noted that the embodiments of this application process pulse signals, higher-order signals, and current signals to obtain continuously varying output signals, i.e., the neutron flux signal F is:

[0183] Where F is the output signal, and the neutron flux detection result is determined based on F. When the pulse signal Fcps is less than the lower limit signal value Nl2 of the second linear overlap interval, the output signal F is the pulse signal Fcps. When the pulse signal Fcps or the higher-order signal Fh is located in the second linear overlap interval [Nl2, Nh2], the output signal F is w4*Fcps+w3*Fh, where w3 is the third weight of the higher-order signal Fh, and w4 is the fourth weight of the pulse signal Fcps. When the pulse signal Fcps is greater than the upper limit signal value Nh2 of the second linear overlap interval, or when the higher-order signal Fh is located between the upper limit signal value Nh2 of the second linear overlap interval and the lower limit signal value Nl1 of the first linear overlap interval, the output signal F is the higher-order signal Fh. When the higher-order signal Fh is located in the first linear overlap interval [Nl1, Nh1], or the current signal is located in the first linear overlap interval [Nl1, Nh1], and the signal noise ratio is... When the signal is less than the predetermined percentage threshold P1, the output signal F is w2*Fh + w1*Fi, where w1 is the first weight of the current signal Fi and w2 is the second weight of the higher-order signal Fh. When the current signal Fi is greater than the upper limit signal value Nh1 of the first linear overlap interval, and the signal noise ratio is... When the signal is less than the predetermined percentage threshold P1, the output signal F is the current signal Fi. When the current signal Fi is greater than the upper limit signal value Nh1 of the first linear overlap interval, and the signal noise ratio is... When the output signal F is greater than or equal to the predetermined percentage threshold P1, it is a higher-order signal Fh.

[0184] The detector signal processing circuit 100 and detector signal processing method provided in this application integrate pulse mode, higher-order mode and Campbell mode together, which can process the signals of the three modes simultaneously, expanding the measurement range of detector 10. The setting of pulse mode circuit 30 and the processing of related signals reduce the influence of gamma rays on neutron flux measurement, improve the accuracy of neutron flux detection results, and simultaneously acquire the signals of the three modes. After weighted processing to calculate neutron flux, there is no gear switching process such as gear shifting, delay, and judgment during the stage of gradual increase of neutron flux, so the signal is smoother.

[0185] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

A detector signal processing circuit, characterized by include: Detector, the detector being used to generate a detection signal; A pulse mode circuit is connected to the detector and is used to perform pulse shaping on the detection signal to obtain a pulse signal. A higher-order mode circuit, comprising multiple Campbell modules connected in parallel, wherein the input terminal of each Campbell module is connected to the detector, and the Campbell module is used to convert the detection signal into a first-order signal; A current-mode circuit is connected to the detector, and the current module is used to convert the detection signal into a current signal; A control module is connected to the output terminals of the pulse-mode circuit, the current-mode circuit, and each of the Campbell modules. The control module is used to determine the higher-order signal of the higher-order mode circuit based on the first-order signal of each Campbell module; when the higher-order signal is greater than the upper limit signal value of a first linear overlap interval, it determines a comparison result between the signal-to-noise ratio in the current signal and a predetermined ratio threshold based on the higher-order signal and the current signal, where the first linear overlap interval is the linear overlap interval between the higher-order signal and the current signal; and when the comparison result indicates that the signal-to-noise ratio in the current signal is greater than or equal to the predetermined ratio threshold, it determines the neutron flux detection result based on the higher-order signal. The circuit according to claim 1, characterized in that Also includes: A preamplifier, the input of which is connected to the detector, and the output of which is connected to the input of the pulse mode circuit and the input of each of the Campbell modules. The circuit according to claim 2, characterized in that The Campbell module includes: A delay unit, the input of which is connected to the preamplifier; A bandpass filter is provided, the input of which is connected to the output of the delay unit. The input of the bandpass filter is also connected to the control module. The delay times of the delay units of the multiple Campbell modules are set in an arithmetic sequence. The circuit according to claim 2, characterized in that The pulse mode circuit includes: A multi-stage amplifier, wherein the input terminal of the multi-stage amplifier is connected to the output terminal of the preamplifier; A comparator, wherein the first input terminal of the comparator is connected to the multi-stage amplifier, and the second input terminal of the comparator is connected to the first voltage source; A pulse shaper, the input of which is connected to the output of the comparator, and the output of which is connected to the control module. The circuit according to claim 1, characterized in that The current-mode circuit includes: transformer; An oscillation circuit is connected to the input terminal of the transformer; A voltage processing circuit, wherein the input terminal of the voltage processing circuit is connected to the first output terminal of the transformer, and the output terminal of the voltage processing circuit is connected to the detector; A voltage feedback circuit, comprising an error amplifier, wherein a first input terminal of the error amplifier is connected to the output terminal of the voltage processing circuit, a second output terminal of the error amplifier is connected to a second voltage source, and the output terminal of the error amplifier is connected to the input terminal of the transformer; A current sampling circuit is provided, wherein the input terminal of the current sampling circuit is connected to the second output terminal of the transformer, and the output terminal of the current sampling circuit is connected to the control module. The circuit according to claim 1, characterized in that The voltage feedback circuit also includes: A voltage sampling circuit, wherein the input terminal of the voltage sampling circuit is connected to the output terminal of the voltage processing circuit, and the output terminal of the voltage sampling circuit is connected to the first input terminal of the error amplifier; A Darlington transistor is used, the input of which is connected to the output of the error amplifier, and the output of which is connected to the input of the transformer. A method of processing a detector signal, characterized in that An application is made in a detector signal processing circuit, the detector signal processing circuit including a detector, a pulse-mode circuit, a higher-order mode circuit, and a current-mode circuit, the higher-order mode circuit including multiple Campbell modules connected in parallel, each of the Campbell modules, the pulse-mode circuit, and the higher-order mode circuit being connected to the detector, the method including: Based on the first-order signals of each of the Campbell modules, the higher-order signals of the higher-order mode circuit are determined. Determine the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit; When the higher-order signal is greater than the upper limit signal value of the first linear overlap block, the comparison result of the signal noise ratio in the current signal and the predetermined ratio threshold is determined based on the higher-order signal and the current signal. If the comparison result indicates that the proportion of signal noise in the current signal is greater than or equal to a predetermined proportion threshold, the neutron flux detection result is determined based on the higher-order signal. The detector signal processing method according to claim 7 is characterized in that, The step of determining the comparison result between the signal-to-noise ratio in the current signal and the predetermined ratio threshold based on the higher-order signal and the current signal includes: Determine a first difference between the current signal and the higher-order signal; Based on the absolute value of the first difference and the ratio of the higher-order signal, the signal-to-noise ratio in the current signal is determined. The signal-to-noise ratio is compared with a predetermined ratio threshold to obtain a comparison result between the signal-to-noise ratio and the predetermined ratio threshold. The detector signal processing method according to claim 7 is characterized in that, After determining the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit, the method further includes: When the higher-order signal or the current signal is located in the first linear overlap interval, based on the higher-order signal and the current signal, it is determined that the signal noise ratio in the current signal is less than a predetermined ratio threshold. Determine the second difference between the higher-order signal and the lower limit signal value of the first linear overlap interval; Determine the third difference between the upper limit signal value and the lower limit signal value of the first linear overlap interval; Based on the second difference and the third difference, a first weight of the current signal and a second weight of the higher-order signal are determined; Based on the first weight and the second weight, a first weighted sum of the current signal and the higher-order signal is determined; Based on the first weighted sum, the neutron flux detection result is determined. The method of claim 7, wherein After determining the higher-order signal of the higher-order mode circuit based on the first-order signal of each of the Campbell modules, the method further includes: Determine the second linear overlap interval between the pulse signal and the higher-order signal; When the pulse signal or the higher-order signal is located in the second linear overlap interval, a fourth difference between the pulse signal and the lower limit signal value of the second linear overlap interval is determined. Determine the fifth difference between the upper limit signal value and the lower limit signal value of the second linear overlap interval; Based on the fourth difference and the fifth difference, the third weight of the higher-order signal and the fourth weight of the pulse signal are determined. Based on the third weight and the fourth weight, a second weighted sum of the higher-order signal and the pulse signal is determined; The neutron flux detection result is determined based on the second weighted sum.

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