Detector signal processing circuit and detector signal processing method

Abstract

The application provides a kind of detector signal processing circuit and detector signal processing method, applied in nuclear technology application field, detector signal processing circuit, comprising: detector is used to generate detection signal;Pulse mode circuit is connected with detector, pulse mode circuit is used to pulse shaping to detection signal, obtains pulse signal;High-order mode circuit includes multiple parallelly connected Campbell modules, the input end of Campbell module is connected with detector, and Campbell module is used to convert detection signal into first-order signal;Current mode circuit is connected with detector, and current mode circuit is used to convert detection signal into current signal;Control module is connected with pulse mode circuit, current mode circuit, the output end of each Campbell module respectively.This embodiment can improve the accuracy of neutron flux detection result, and expand the measurement range of detector.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear technology application, and particularly relates to a detector signal processing circuit and a detector signal processing method. BACKGROUND

[0002] A fission chamber detector is a neutron detector with a wide measurement range. It is widely used in neutron measurement in a high gamma ray environment due to its high gamma ray consistency. The fission chamber detector has three modes, namely, a pulse mode, a mean square mode and a current mode. The pulse mode and the mean square mode have the ability to suppress gamma noise, and the current mode signal is proportional to the gamma dose. In a neutron flux environment with a high proportion of gamma rays in the reactor, because the three modes have different degrees of gamma ray suppression, the measurement results of the three modes have large deviations at the same neutron flux level. Therefore, the detector signal processing circuit in the related art can usually only process the pulse mode signal and the mean square mode signal of the fission chamber detector, or can only process the current mode signal, and the measurement range is narrow. SUMMARY

[0003] The embodiments of the present application provide a detector signal processing circuit and a detector signal processing method, which can improve the accuracy of the neutron flux detection result and expand the measurement range of the detector.

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

[0005] a detector, configured to generate a detection signal;

[0006] a pulse mode circuit, connected with the detector, configured to pulse shape the detection signal to obtain a pulse signal;

[0007] a high-order mode circuit, comprising a plurality of Campbell modules connected in parallel, an input end of the Campbell module being connected with the detector, the Campbell module being configured to convert the detection signal into a first-order signal;

[0008] a current mode circuit, connected with the detector, configured to convert the detection signal into a current signal;

[0009] A control module is connected with the pulse mode circuit, the current mode circuit and the output end of each Campbell module respectively, and is configured to determine a high-order signal of the high-order mode circuit based on the first-order signal of each Campbell module, determine a comparison result of a signal noise ratio in the current signal and a predetermined ratio threshold based on the high-order signal and the current signal when the high-order signal is greater than an upper limit signal value of a first linear overlap interval, and determine a neutron flux detection result based on the high-order signal when the comparison result indicates that the signal noise ratio in the current signal is greater than or equal to the predetermined ratio threshold.

[0010] According to the first aspect of the embodiment of the present application, the detector signal processing circuit has at least the following beneficial effects: the detector signal processing circuit includes a high-order mode circuit, the high-order mode circuit adopts a high-order Campbell theorem, and includes a plurality of Campbell modules connected in parallel. Compared with the mean square mode circuit, the high-order mode circuit has a stronger degree of suppression on gamma rays, and the higher the order of the high-order mode circuit, that is, the more the number of Campbell modules, the stronger the degree of suppression on gamma rays, the stronger the resolution capability on neutrons, and the more accurate the high-order signal. In addition, the circuit signal of the current mode circuit is proportional to the gamma dose. To reduce the influence of gamma rays, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval, that is, the neutron flux is located in the measurement interval of the high-order mode circuit or the current mode, the signal noise ratio in the current signal is determined to be greater than or equal to the predetermined ratio threshold based on the high-order signal and the current signal, and then it is determined that the content of gamma rays is high and the influence on the current signal is large. Therefore, the final output is based on the high-order signal, and the neutron flux detection result is determined based on the high-order signal. The detector signal processing circuit of the embodiment of the present application includes a pulse mode circuit, a high-order mode circuit and a current mode circuit, can process signals of three modes at the same time, expands the measurement range of the detector, and reduces the influence of gamma rays on the measurement of neutron flux by the setting of the high-order mode circuit and the processing of related signals, and improves the accuracy of the neutron flux detection result.

[0011] According to some embodiments of the present application, the detector signal processing circuit further includes:

[0012] A preamplifier, an input end of the preamplifier is connected with the detector, and an output end of the preamplifier is connected with an input end of the pulse mode circuit and an input end of each Campbell module.

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

[0014] A delay unit, an input end of the delay unit is connected with the preamplifier.

[0015] a band-pass filter, an input end of the band-pass filter being connected with an output end of the delay unit, the input end of the band-pass filter being connected with the control module, and delay time corresponding to the delay unit of each of the plurality of Campbell modules being arranged in an arithmetic sequence.

[0016] According to some embodiments of the present application, the pulse mode circuit comprises:

[0017] a multi-stage amplifier, an input end of the multi-stage amplifier being connected with an output end of the preamplifier;

[0018] a comparator, a first input end of the comparator being connected with the multi-stage amplifier, a second input end of the comparator being connected with a first voltage source;

[0019] a pulse shaper, an input end of the pulse shaper being connected with an output end of the comparator, an output end of the pulse shaper being connected with the control module.

[0020] According to some embodiments of the present application, the current mode circuit comprises:

[0021] a transformer;

[0022] an oscillation circuit, the oscillation circuit being connected with an input end of the transformer;

[0023] a voltage processing circuit, an input end of the voltage processing circuit being connected with a first output end of the transformer, an output end of the voltage processing circuit being connected with the detector;

[0024] a voltage feedback circuit, the voltage feedback circuit comprising an error amplifier, a first input end of the error amplifier being connected with an output end of the voltage processing circuit, a second output end of the error amplifier being connected with a second voltage source, an output end of the error amplifier being connected with an input end of the transformer;

[0025] a current sampling circuit, an input end of the current sampling circuit being connected with a second output end of the transformer, an output end of the current sampling circuit being connected with the control module.

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

[0027] a voltage sampling circuit, an input end of the voltage sampling circuit being connected with an output end of the voltage processing circuit, an output end of the voltage sampling circuit being connected with a first input end of the error amplifier;

[0028] a Darlington tube, an input end of the Darlington tube being connected with an output end of the error amplifier, an output end of the Darlington tube being connected with an input end of the transformer.

[0029] In a second aspect, the embodiments of the present application provide a detector signal processing method, applied to a detector signal processing circuit, the detector signal processing circuit comprising a detector, a pulse mode circuit, a high-order mode circuit and a current mode circuit, the high-order mode circuit comprising a plurality of Campbell modules connected in parallel, each Campbell module, the pulse mode circuit and the high-order mode circuit being connected with the detector, and the method comprising:

[0030] determining a high-order signal of the high-order mode circuit based on a first-order signal of each Campbell module;

[0031] determining a first linear overlap interval of the high-order signal and a current signal of the current mode circuit;

[0032] when the high-order signal is greater than an upper limit signal value of the first linear overlap interval, determining a comparison result of a signal noise ratio in the current signal and a predetermined ratio threshold based on the high-order signal and the current signal;

[0033] in a case where the comparison result indicates that the signal noise ratio in the current signal is greater than or equal to the predetermined ratio threshold, determining a neutron flux detection result based on the high-order signal.

[0034] According to some embodiments of the present application, the determination of the comparison result of the signal noise ratio in the current signal and the predetermined ratio threshold based on the high-order signal and the current signal comprises:

[0035] determining a first difference value of the current signal and the high-order signal;

[0036] determining the signal noise ratio in the current signal based on an absolute value of the first difference value and a ratio of the high-order signal;

[0037] comparing the signal noise ratio with the predetermined ratio threshold to obtain the comparison result of the signal noise ratio and the predetermined ratio threshold.

[0038] According to some embodiments of the present application, after the determination of the first linear overlap interval of the high-order signal and the current signal of the current mode circuit, the method further comprises:

[0039] when the high-order signal or the current signal is located in the first linear overlap interval, determining that the signal noise ratio in the current signal is less than the predetermined ratio threshold based on the high-order signal and the current signal;

[0040] determining a second difference value of the high-order signal and a lower limit signal value of the first linear overlap interval;

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

[0042] determining a first weight of the current signal and a second weight of the high-order signal based on the second difference value and the third difference value;

[0043] determining a first weighted sum of the current signal and the high-order signal based on the first weight and the second weight;

[0044] determining a neutron flux detection result based on the first weighted sum.

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

[0046] determining a second linear overlap interval of the pulse signal and the high-order signal;

[0047] determining a fourth difference value of the pulse signal and the lower limit signal value of the second linear overlap interval when the pulse signal or the high-order signal is in the second linear overlap interval;

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

[0049] determining a third weight of the high-order signal and a fourth weight of the pulse signal based on the fourth difference value and the fifth difference value;

[0050] determining a second weighted sum of the high-order signal and the pulse signal based on the third weight and the fourth weight;

[0051] determining a neutron flux detection result based on the second weighted sum.

[0052] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0055] Figure 2 is a schematic diagram of a first linear overlap interval and a second linear overlap interval provided by an embodiment of the present application;

[0056] Figure 3 is a schematic diagram of a preamplifier provided by an embodiment of the present application;

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

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

[0059] Figure 6 is a schematic diagram of a band-pass filter in a Campbell module provided by an embodiment of the present application;

[0060] Figure 7 is a schematic diagram of a pulse mode circuit provided by an embodiment of the present application;

[0061] Figure 8 is a structural block diagram of a current mode circuit provided by an embodiment of the present application;

[0062] Figure 9 is a schematic diagram of a current mode circuit provided by an embodiment of the present application;

[0063] Figure 10 is a flow chart of a detector signal processing method provided by an embodiment of the present application;

[0064] Figure 11 is Figure 10 is a flow chart of a comparison result between a signal noise ratio and a predetermined ratio threshold in step S300 of

[0065] Figure 12 is another flow chart of a detector signal processing method provided by an embodiment of the present application;

[0066] Figure 13 is a flow chart of a detector signal processing method when a pulse signal or a high-order signal is in a second linear overlap interval provided by an embodiment of the present application. DETAILED DESCRIPTION

[0067] In the following description, for the purposes of explanation and not limitation, specific details are set forth, such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the embodiments of the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the embodiments of the present 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 can be performed in an order different from that in the flowchart. The terms "first", "second", and the like in the description and claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0069] It should also be understood that the description of the reference "one embodiment" or "some embodiments" and the like in the description of the embodiments of the present application means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in other some embodiments" and the like appearing in different places in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "include but not limited to", unless otherwise specifically emphasized.

[0070] In the description of the present application, not less than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If the first, second is described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features. It should be understood that the orientation description, such as up, down, front, back, left, right, etc. indicates the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0071] The fission chamber detector is a neutron detector with wide measurement range, and is widely used in neutron measurement in high gamma ray environment due to its high gamma ray consistency capability. The fission chamber detector has three modes, namely pulse mode, mean square mode and current mode. Among them, the pulse mode and the mean square mode have the ability to suppress gamma noise, and the current mode signal is proportional to the gamma dose. In the neutron flux environment with a high proportion of gamma rays in the reactor, because the suppression degree of gamma rays is different in the three modes, the measurement results of the three modes appear large deviation at the same neutron flux level. Therefore, the signal processing circuit of the detector in the related art can usually only process the pulse mode signal and the mean square mode signal of the fission chamber detector, or can only process the current mode signal, and the measurement range is narrow.

[0072] Based on this, the embodiment of the present application provides a detector signal processing circuit and a detector signal processing method. The detector signal processing circuit provided by the embodiment of the present application can improve the accuracy of the neutron flux detection result and expand the measurement range of the detector.

[0073] The embodiment of the present application is further described below with reference to the accompanying drawings.

[0074] With reference to Figure 1 and Figure 4 , the embodiment of the present 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] The detector 10 is configured to generate a detection signal.

[0076] The pulse mode circuit 20 is connected with the detector 10, and the pulse mode circuit 20 is configured to pulse-shape the detection signal to obtain a pulse signal.

[0077] The pulse mode circuit 30 includes a plurality of Campbell modules 31 connected in parallel, and the input end of the Campbell module 31 is connected with the detector 10. The Campbell module 31 is configured to convert the detection signal into a first-order signal.

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

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

[0080] The control module 50 is specifically configured to:

[0081] Based on the first-order signal of each Campbell module 31, the high-order signal of the pulse mode circuit 30 is determined.

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

[0083] In the case where the comparison result indicates that the signal noise ratio in the current signal is greater than or equal to the predetermined ratio threshold, the neutron flux detection result is determined based on the high-order signal.

[0084] It should be noted that the detector 10 is specifically a fission chamber detector, which can be used for the measurement of the ex-core neutron flux and generate a detection signal. When the neutron flux level is relatively low, the detection signal is a pulse form of electrical signal, and the frequency of the pulse is proportional to the neutron flux level. As the neutron flux level increases, the pulse form of signal is superimposed on each other, and the detection signal is a pulsating direct current signal with a certain frequency.

[0085] It should be noted that in the pulse mode, the fission chamber detector can detect and count individual neutron events, which is suitable for low neutron flux environment. The advantage of the pulse mode is that it can effectively distinguish and count individual neutron events, thereby providing accurate neutron flux measurement. In addition, in a low neutron flux environment, the control module 50 can only detect the pulse signal output by the pulse mode circuit 20. The control module 50 performs pulse counting on the pulse signal, thereby performing neutron flux statistics. In a low neutron flux environment, the count rate of the detection signal output by the detector 10 is usually less than 10 5 cps, that is, the number of detected radiations per second is less than 10 5 .

[0086] Referring to Figure 1 , the control module 50 is a field programmable gate array (FPGA), which can process the pulse signal, calculate the count rate by calculating the number of pulses in a unit time, and the count rate is proportional to the neutron flux. In addition, the pulse signal is input to the FPGA through the buffer, which can reduce the attenuation, distortion and other conditions of the pulse signal, and improve the stability of the detector signal processing circuit 100.

[0087] It should be noted that the pulse mode circuit 30, that is, the high-order Campbell circuit, is realized based on the high-order Campbell theorem. Specifically, the pulse mode circuit 30 includes a plurality of Campbell modules 31, the more the number of Campbell modules 31, the higher the order of Campbell theorem, and the stronger the suppression of γ noise. The higher the order signal determined based on the first order signal output by each Campbell module 31 is more accurate.

[0088] The pulse mode circuit 30 realizes the measurement of the neutron flux by analyzing the fluctuation of the direct current, which is suitable for the medium fission range, that is, the medium neutron flux environment. At this time, the count rate is usually 10 5 cps to 10 10 cps.

[0089] In the medium neutron flux environment, the control module 50 detects the first order signal output by the Campbell module 31, and determines the high order signal of the pulse mode circuit 30 based on the first order signal of each Campbell module 31. The number of Campbell modules 31 in the pulse mode circuit 30 is different, and the calculation formula for determining the high order signal is also different. Assuming that the collected voltages, i.e. the first order signals, of n Campbell modules 31 in the pulse mode circuit 30 are V1, V2, …, Vn, the collected voltages are converted into a variable proportional to the neutron flux according to the following formula :

[0090] ,

[0091] wherein, is the high order signal, represents the number of Campbell modules 31 in the pulse mode circuit 30, is a positive integer, which represents that the pulse mode circuit 30 includes Campbell modules 31, is a positive integer in . represents the corresponding collected voltage, i.e. the first order signal, of the th Campbell module 31 in the pulse mode circuit 30.

[0092] It should be noted that since the dimensions of the three modes are different, the control module 50 converts the current signal, the high order signal and the pulse signal into corresponding neutron flux signals for processing. Assuming that the current signal is , the neutron sensitivity corresponding to the current signal is , and the neutron flux signal corresponding to the current signal is . Assuming that the pulse signal is , the neutron sensitivity corresponding to the pulse signal is , and the neutron flux signal in the pulse mode is . If the high order signal is , the neutron sensitivity corresponding to the high order signal is . The comparison between the high order signal and the current signal is also based on the corresponding neutron flux signals.

[0093] In addition, when the neutron flux is near the critical value between the low neutron flux and the medium neutron flux, the control module 50 detects both the pulse signal and the high order signal, and at this time, the neutron flux can be counted according to the weight based on the overlapping area of the two.

[0094] It should be noted that the current mode is mainly used in the high fissile rate range, i.e. in the high neutron flux environment. The current mode is suitable for the case where frequent pulses cannot be separated, and generates a continuous current, so that the average direct current from the detector 10 can be measured. However, the current signal of the current mode circuit 40 is proportional to both the neutron flux and the gamma dose. In a high gamma environment, the measurement error determined based on the current mode is large.

[0095] To solve this problem, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval, the proportion of signal noise in the current signal is determined based on the high-order signal and the current signal. The signal noise in the current signal is caused by gamma rays. Based on the proportion of signal noise, the error between the neutron flux determined based on the current signal and the actual neutron flux can be determined. When the proportion of signal noise is greater than or equal to a predetermined proportion threshold, the error between the neutron flux determined based on the current signal and the actual neutron flux is large. Therefore, the high-order signal is taken as the final output signal, and the detection result of the neutron flux is determined based on the high-order signal.

[0096] The first linear overlap interval is the linear overlap interval of the high-order signal and the current signal. There is a linear overlap interval and a saturation interval between the high-order signal and the current signal. For details, refer to Figure 2 , The first linear overlap interval is the linear overlap interval between the high-order signal and the current signal. In the first linear overlap interval, since the control module 50 detects the high-order signal and the current signal at the same time, the high-order signal and the current signal need to be connected, and in the saturation interval, although the high-order signal and the current signal are detected at the same time, in order to realize the smooth transition between the signals, the current signal is usually taken as the output signal.

[0097] However, the current signal is proportional to the gamma dose, and in order to reduce the influence of gamma rays on the accuracy of the detected neutron flux, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval and the proportion of signal noise is greater than or equal to a predetermined proportion threshold, the detection result of the neutron flux is determined based on the high-order signal.

[0098] It should be noted that the predetermined proportion threshold can be set as needed. If the proportion of signal noise in the current signal is greater than or equal to the predetermined proportion threshold, the measurement result of the neutron flux is determined based on the high-order signal. If the proportion of signal noise in the current signal is less than the predetermined proportion threshold, the measurement result of the neutron flux is determined based on the current signal.

[0099] It should be noted that the detector signal processing circuit 100 provided by the embodiments of the present application is only applicable to a fission chamber detector.

[0100] It should be noted that the detector signal processing circuit 100 includes the pulse mode circuit 30, the pulse mode circuit 30 adopts the high-order Campbell theorem, which includes a plurality of Campbell modules 31 connected in parallel, compared with the mean square mode circuit, the pulse mode circuit 30 has stronger suppression degree to the gamma rays, and the higher the order of the pulse mode circuit 30, that is, the more the number of the Campbell modules 31, the stronger the suppression degree to the gamma rays, the stronger the resolution ability to the neutrons, and the more accurate the high-order signal. In addition, the circuit signal of the current mode circuit 40 is proportional to the gamma dose, in order to reduce the influence of the gamma rays, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval, that is, the neutron flux is located in the measurement interval of the pulse mode circuit 30 or the current mode circuit 40, based on the high-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, and then it is determined that the content of the gamma rays is higher, and the influence on the current signal is greater, therefore, finally, the high-order signal is output as the standard, and the neutron flux detection result is determined based on the high-order signal. The detector signal processing circuit 100 of the embodiment of the present application includes the pulse mode circuit 20, the pulse mode circuit 30 and the current mode circuit 40, which can process signals of three modes at the same time, expand the measurement range of the detector 10, and the setting of the pulse mode circuit 30 and the processing of the related signals reduce the influence of the gamma rays on the neutron flux measurement, and improve the accuracy of the neutron flux detection result.

[0101] In an embodiment, referring to Figure 1 , the detector signal processing circuit 100 further includes a preamplifier 60, the input end of the preamplifier 60 is connected with the detector 10, and the output end of the preamplifier 60 is connected with the input end of the pulse mode circuit 20 and the input end of each Campbell module 31.

[0102] It should be noted that the preamplifier 60 is used for amplifying the detection signal output by the detector 10, improving the strength of the detection signal, and facilitating the pulse mode circuit 20 and each Campbell module 31 to process the detection signal.

[0103] Referring to Figure 3 , Figure 3The preamplifier 60 circuit diagram provided by the embodiment of the present application. The corresponding equivalent circuit of the probe and the 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 probe 10, R1 can be considered as the filter resistance of the probe 10, and the high voltage power supply and the filter resistance of the probe 10 are combined to enable the probe 10 to work normally. In addition, the capacitance C1, the resistance R2, the diode D1, the diode D2, the amplifier A1 and the resistance Rf and the capacitance Cf jointly constitute the preamplifier 60 circuit. Among them, A1 can be selected from an integrated operational amplifier or a discrete amplifier built by a triode, C1 is a high voltage capacitor, C1 is mainly used for isolating high voltage, R2 is a matching resistance of the cable, and the size is usually 50 ohms (Ω). D1 and D2 are used for surge protection to reduce the destructive effect of the current impact caused by high voltage mutation on the amplifier A1. Rf is the feedback resistance of the amplifier, and Cf is the feedback capacitance of the amplifier. Therefore, the transfer function of the circuit can be determined as:

[0104]

[0105] Among them, is the transfer function of the preamplifier 60, is the output voltage of the preamplifier 60, is the output current of the amplifier, is the independent variable of Laplace transform, usually represented as a complex variable. is the value of the capacitance C1, is the value of the capacitance C0, is the time constant corresponding to the capacitance C1 and the resistance R1, and , is the time constant corresponding to the capacitance Cf and the resistance Rf, and , is the value of the resistance R1, is the value of the resistance Rf.

[0106] In an embodiment, referring to Figure 4 , the Campbell module 31 includes a delay unit and a band-pass filter, the input end of the delay unit is connected with the preamplifier 60, the output end of the delay unit is connected with the input end of the band-pass filter, the input end of the band-pass filter is connected with the control module 50, and the delay time corresponding to the delay units of the plurality of Campbell modules 31 is arranged in an arithmetic sequence.

[0107] It should be noted that the detection signal is amplified by the preamplifier 60 and then processed by the plurality of Campbell modules 31 of the pulse mode circuit 30. Each Campbell module 31 includes a delay unit and a band-pass filter, the delay time corresponding to the delay units of the plurality of Campbell modules 31 is arranged in an arithmetic sequence, and the band-pass filters of the plurality of Campbell modules 31 are the same.

[0108] The delay time of the plurality of delay units is an arithmetic sequence, and the delay time can be expressed as Tdn=Td0+T*n, where Tdn is the delay time of the nth delay unit, Td0 is a time offset, which is determined by the pulse width of the signal output by the preamplifier 60 and is irrelevant to the pulse width of the probe signal. The pulse width of the signal output by the preamplifier 60 is always a fixed value regardless of the pulse width of the probe signal. Assuming that the pulse width of the signal output by the preamplifier 60 is 100 microseconds, the time offset Td0 is 100 microseconds. T is the difference in delay time between adjacent two delay units, which can be set to 1s, and the delay time of the n delay units is divided into 101 microseconds, 102 microseconds, …, 100+n microseconds.

[0109] The delay unit can be set as a transmission line with an arithmetic sequence length, or as an all-pass filter. If the delay unit is an all-pass filter, the delay time can be set by controlling the phase. The delay unit is set to facilitate the collection of the first-order signals corresponding to different Campbell modules 31.

[0110] Referring to Figure 5 , the delay unit is set as an all-pass filter, the input end Vin of the delay unit is connected with the preamplifier 60, and the output end Vout of the delay unit is connected with the input end of the band-pass filter. R37, R38, R39 and C21 jointly constitute an all-pass filter. The all-pass filter realizes phase adjustment by introducing phase delay, without affecting the frequency characteristics of the signal. Therefore, the delay time of the plurality of delay units can be set as an arithmetic sequence through the all-pass filter, without affecting the signal input by the preamplifier 60.

[0111] The band-pass filter in the Campbell module 31 is shown in Figure 6 . In the band-pass filter shown in Figure 6 , C4, C5, R10, R12 and U12 constitute a second-order active high-pass filter, R13, R14, C6, C8 and U13 constitute a second-order active low-pass filter, and the second-order active high-pass filter and the second-order active low-pass filter jointly constitute the band-pass filter. In order to further enhance the clarity and recognizability of the signal input to the band-pass filter, the embodiment of the application adds a high-pass filter circuit and a first amplifier in front of the band-pass filter. Referring to Figure 6, Vin represents the detection signal processed via the preamplifier 60 and the delay unit, C12, R21, C3, R11, C7, R15, C17, and R23 constitute a high-pass filter circuit for suppressing low-frequency noise and enhancing high-frequency signals, thereby improving the clarity and recognizability of the signals. To further enhance the clarity and recognizability of the detection signal, U10, R6, and R7 constitute an amplifier for positively amplifying Vin. In addition, the second amplifier composed of U19, R36, and R35 is arranged after the band-pass filter for amplifying the first-order signal, Figure 6

[0112] The delay unit and the band-pass filter constitute independent channels to respectively measure the detection signal and obtain the first-order signal, and the control module 50 obtains the high-order signal based on the plurality of first-order signals, thereby realizing the application of the high-order Campbell theorem, and the determination of the high-order signal can further enhance the suppression of gamma rays and improve the measurement accuracy.

[0113] In an embodiment, referring to Figure 1 , the pulse mode circuit 20 includes a multi-stage amplifier, a comparator, and a pulse shaper. The input end of the multi-stage amplifier is connected to the output end of the preamplifier 60. The first input end of the comparator is connected to the multi-stage amplifier, and the second input end of the comparator is connected to the first voltage source. The input end of the pulse shaper is connected to the output end of the comparator, and the output end of the pulse shaper is connected to the control module 50.

[0114] It should be noted that the multi-stage amplifier is used to further amplify the signal output by the preamplifier 60 to improve the signal strength. The first input end of the comparator is connected to the multi-stage amplifier, and the second input end of the comparator is connected to the first voltage source. The comparator compares the pulse signal amplified by the multi-stage 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.

[0115] The discrimination threshold voltage can be set as needed, and the value range of the discrimination threshold voltage is usually 0 to 5V.

[0116] Referring to Figure 7 , Figure 7 is a schematic diagram of the pulse mode circuit 20 provided in the embodiment of the present application. Vin is the detection signal processed by the preamplifier 60. U9, R4, and R5 constitute a first-stage amplification circuit, and U11, R8, and R9 constitute a second-stage amplification circuit. The first-stage amplification circuit and the second-stage amplification circuit together constitute Figure 1 ​The multi-stage amplifier in the pulse shaping circuit is composed of U11, U12, U13, U14, R33, R34, C19 and C20. U11 is a comparator, which compares the input signal with the first voltage source, and outputs a pulse signal. U12 is a multi-stage amplifier, which amplifies the pulse signal output by U11. U13 is a comparator, which compares the pulse signal output by U12 with the second voltage source, and outputs a pulse signal. U14 is a comparator, which compares the pulse signal output by U11 with the voltage value of the first voltage source, and outputs a standard TTL level pulse signal. The pulse shaper includes a monostable logic chip U2A, a resistor R34 and a capacitor C20, which 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, and the greater the product of R34 and C20, the greater the pulse width. In addition, in order to improve the clarity and recognition of the signal input to the band-pass filter, the application embodiment is provided with a high-pass filter circuit in front of the band-pass filter, Figure 7 C2, R3, C9, R16, C10 and R17 in the high-pass filter circuit.

[0117] 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.

[0118] In an embodiment, referring to Figure 1 and Figure 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 end of the transformer. The input end of the voltage processing circuit 42 is connected to the first output end of the transformer, and the output end of the voltage processing circuit 42 is connected to the detector 10. The voltage feedback circuit 43 includes an error amplifier, the first input end of the error amplifier is connected to the output end of the voltage processing circuit 42, the second output end of the error amplifier is connected to the second voltage source, and the output end of the error amplifier is connected to the input end of the transformer. The input end of the current sampling circuit 44 is connected to the second output end of the transformer, and the output end of the current sampling circuit 44 is connected to the control module 50.

[0119] It should be noted that the oscillation circuit 41 is connected to the input end of the transformer, which is used to generate a continuous oscillation signal. The transformer is used to convert the input oscillation signal into a high-voltage signal, and the high-voltage signal is processed by the voltage processing circuit 42 to provide operating voltage for the detector 10.

[0120] The voltage feedback circuit 43 includes an error amplifier, the first input end of the error amplifier is connected to the output end of the voltage processing circuit 42, the second output end of the error amplifier is connected to the second voltage source, and the output end of the error amplifier is connected to the input end of the transformer. The error amplifier is used to compare 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, so as to feedback to the transformer, and then adjust the output voltage value of the voltage processing circuit 42, so that the output voltage value of the voltage processing circuit 42 is equal to the high-voltage set value.

[0121] The current sampling circuit 44 is connected with the input end and the second output end of the transformer, so as to sample the current value in the detection signal of the detector 10, and output to the control module 50, so as to realize the neutron detection under the high neutron flux.

[0122] In an embodiment, referring to Figure 1 and Figure 8 , the voltage feedback circuit 43 further comprises a voltage sampling circuit and a Darlington tube. The input end of the voltage sampling circuit is connected with the output end of the voltage processing circuit 42, and the output end of the voltage sampling circuit is connected with the first input end of the error amplifier. The input end of the Darlington tube is connected with the output end of the error amplifier, and the output end of the Darlington tube is connected with the input end of the transformer.

[0123] 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 compares 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.

[0124] The Darlington tube is a composite transistor composed of two or more transistors in series, which has the characteristics of high current gain and high input impedance. The working principle of the Darlington tube is to connect two transistors in series, the collector of the first transistor is connected with the base of the second transistor, and the emitter of the first transistor is connected with the emitter of the second transistor, thereby forming an equivalent new transistor. This configuration allows the amplified current of the first transistor to be further amplified by the second transistor, thereby achieving very high current gain and enhancing the output signal of the error amplifier.

[0125] Figure 9 A schematic diagram of the current mode circuit 40 provided in the embodiment of the present application is shown. Referring to Figure 8 and Figure 9 , T1 is a transformer. The voltage processing circuit 42 comprises a voltage doubling circuit and a high voltage filtering circuit, wherein the input end of the voltage doubling circuit is connected with the first output end of the transformer, the output end of the voltage doubling circuit is connected with the input end of the high voltage filtering circuit, and the output end of the high voltage filtering circuit is connected with the detector 10. The voltage doubling circuit comprises D1, C14, D2, C13 as shown in Figure 9 , the voltage doubling circuit is used to convert the output voltage of the transformer into a higher output voltage, and the high voltage filtering circuit comprises R18, C16, C15, R19, R20, which is used to filter out low frequency noise and enhance the voltage signal, thereby providing high voltage HV for the detector 10. Figure 9R26, R27, U17 in the figure constitute a high voltage sampling circuit, wherein R26 and R27 are used for sampling and dividing the high voltage HV output by the voltage processing circuit 42. U16, R25, R24, C18, C19 constitute an error amplifier in the voltage feedback circuit 43, which compares the high voltage sampling value with the high voltage set value, thereby adjusting Q3 and Q4, i.e. Darlington tube, by negative feedback, so as to drive the transformer and convert the appropriate high voltage. R22, R29, R28, D3, U18, D4, R30, R31, R33, R32, U15 constitute a current sampling circuit 44, which samples and processes the output voltage of the transformer, thereby outputting the voltage V_Iout, which is the voltage corresponding to the output current in the current signal. The oscillation circuit 41 includes a triode and an oscillator, Q1 and Q2 are triodes in the oscillation circuit 41, and U1A, U1B, U1C, U21, R37, R38, C21, C22 constitute an oscillator, wherein U1A, U1B, U1C are Schmidt inverters.

[0126] With reference to Figure 1 The voltage acquisition circuit converts the output voltage V_Iout into a digital signal, and the FPGA processes the converted digital signal.

[0127] It should be noted that the detector signal processing circuit 100 in the embodiment of the present application includes a pulse mode circuit 30, which adopts a high-order Campbell theorem, and includes a plurality of Campbell modules 31 connected in parallel. Compared with the mean square mode circuit, the pulse mode circuit 30 has a stronger suppression degree on the gamma rays, and the higher the order of the pulse mode circuit 30, i.e. the more the number of Campbell modules 31, the stronger the suppression degree on the gamma rays, the stronger the resolution ability on the neutrons, and the more accurate the high-order signal. In addition, the circuit signal of the current mode circuit 40 is proportional to the gamma dose. In order to reduce the influence of the gamma rays, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e. the neutron flux is located in the measurement interval of the pulse mode circuit 30 or the current mode, based on the high-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, and it is further determined that the content of the gamma rays is relatively high and the influence on the current signal is relatively large. Therefore, the final output is based on the high-order signal, and the neutron flux detection result is determined based on the high-order signal. The detector signal processing circuit 100 of the present application includes the pulse mode circuit 20, the pulse mode circuit 30 and the current mode circuit 40, which can process signals of three modes at the same time, expand the measurement range of the detector 10, and reduce the influence of the gamma rays on the neutron flux measurement by setting the pulse mode circuit 30 and processing the related signals, thereby improving the accuracy of the neutron flux detection result.

[0128] 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:

[0129] Step S100: Determine the higher-order signals of the higher-order mode circuit based on the first-order signals of each Campbell module.

[0130] Step S200: Determine the first linear overlap interval between the higher-order signal and the current signal of the current-mode circuit.

[0131] Step S300: When the higher-order signal is greater than the upper limit signal value of the first linear overlap interval, 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.

[0132] 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.

[0133] 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.

[0134] 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 variables proportional to the neutron flux using the following formula. :

[0135] ,

[0136] in, For higher-order signals, This indicates the number of Campbell modules 31 in the pulse-mode circuit 30. A positive integer, representing the pulse mode circuit 30 including Campbell module 31, It is located in Positive integers in the range. Indicating the pulse mode circuit 30, the first The corresponding acquisition voltage of each Campbell module 31, i.e., the first-order signal.

[0137] It should be noted that, since the dimensions of the three modes are different, the control module 50 will convert the current signal, the high-order signal and the pulse signal into corresponding neutron flux signals for processing. Assuming that the current signal is , the neutron sensitivity corresponding to the current signal is , and the neutron flux signal corresponding to the current signal is . Assuming that the pulse signal is , the neutron sensitivity corresponding to the pulse signal is , and the neutron flux signal in the pulse mode is . If the high-order signal is , the neutron sensitivity corresponding to the high-order signal is . The comparison between the high-order signal and the current signal is also based on the corresponding neutron flux signals.

[0138] The first linear overlap interval is the linear overlap interval of the high-order signal and the current signal of the current mode circuit 40. In addition, the determination of the first linear overlap interval is also based on the neutron flux signal.

[0139] There is a linear overlap region and a saturation region between the high-order signal and the current signal. Referring to Figure 2 , is the linear overlap region between the high-order signal and the current signal, i.e. the first linear overlap interval. In the first linear overlap interval, since the control module 50 detects the high-order signal and the current signal at the same time, it is necessary to connect the high-order signal and the current signal, and in the saturation region, although the high-order signal and the current signal are detected at the same time, in order to realize the smooth transition between the signals, the current signal is usually taken as the output signal.

[0140] It should be noted that the signal noise ratio refers to the proportion of signal noise caused by the gamma signal in the current signal.

[0141] The current mode is mainly used in the high fissile rate range, i.e. in the high neutron flux environment. The current mode is suitable for the case where frequent pulses cannot be separated, generates continuous current, and thus can measure the average value of the direct current from the detector 10. However, the current signal of the current mode circuit 40 is proportional to the neutron flux and the gamma dose. In a high gamma environment, the measurement error determined based on the current mode is large.

[0142] To solve this problem, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval, the proportion of signal noise in the current signal is determined based on the high-order signal and the current signal. The signal noise in the current signal is caused by the gamma rays. Based on the proportion of signal noise, the error between the neutron flux determined based on the current signal and the actual neutron flux can be determined. When the proportion of signal noise is greater than or equal to a predetermined proportion threshold, the error between the neutron flux determined based on the current signal and the actual neutron flux is larger. Therefore, the high-order signal is taken as the final output signal, and the detection result of the neutron flux is determined based on the high-order signal.

[0143] It should be noted that the predetermined proportion threshold can be set as needed. If the proportion of signal noise in the current signal is greater than or equal to the predetermined proportion threshold, the measurement result of the neutron flux is determined based on the high-order signal. If the proportion of signal noise in the current signal is less than the predetermined proportion threshold, the measurement result of the neutron flux is determined based on the current signal.

[0144] It should be noted that the detector signal processing method provided by the embodiments of the present application is only applicable to fission chamber detectors.

[0145] It should be noted that the detector signal processing circuit 100 includes a pulse mode circuit 30, which adopts a high-order Campbell theorem, including a plurality of Campbell modules 31 connected in parallel. Compared with the mean square mode circuit, the pulse mode circuit 30 has a stronger degree of suppression of gamma rays, and the higher the order of the pulse mode circuit 30, i.e. the more the number of Campbell modules 31, the stronger the degree of suppression of gamma rays, and the stronger the resolution capability of neutrons, and the more accurate the high-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 high-order signal is greater than the upper limit signal value of the first linear overlap interval, i.e. the neutron flux is located in the measurement interval of the pulse mode circuit 30 or the current mode, the proportion of signal noise in the current signal is determined based on the high-order signal and the current signal. The proportion of signal noise in the current signal is greater than or equal to the predetermined proportion threshold, and the content of gamma rays is determined to be relatively high, which has a greater impact on the current signal. Therefore, the final output is based on the high-order signal, and the detection result of the neutron flux is determined based on the high-order signal. The detector signal processing circuit 100 of the embodiments of the present application includes the pulse mode circuit 20, the pulse mode circuit 30 and the current mode circuit 40, which can process signals of three modes at the same time, expand the measurement range of the detector 10, and reduce the influence of gamma rays on the measurement of neutron flux, and improve the accuracy of the detection result of neutron flux.

[0146] In an embodiment, referring to Figure 11 , the step S300 includes but is not limited to the following steps:

[0147] Step S310, determine a first difference value of the current signal and the high-order signal.

[0148] Step S320, determine a signal noise ratio in the current signal based on an absolute value of the first difference value and a ratio of the high-order signal.

[0149] Step S330, compare the signal noise ratio with a predetermined ratio threshold to obtain a comparison result of the signal noise ratio and the predetermined ratio threshold.

[0150] It should be noted that the first difference value refers to a ratio between the current signal and the high-order signal. The signal noise ratio in the current signal can be expressed as: wherein, is the current signal, is the high-order signal, that is, the first difference value of the current signal and the high-order signal.

[0151] The current signal is proportional to the neutron flux and the gamma dose. Therefore, under the condition that the neutron flux is constant, the more the gamma dose, the larger the current signal, and the first difference value of the current signal and the high-order signal is larger and positive. Therefore, based on the ratio of the first difference value and the high-order signal, the signal noise ratio in the current signal can be determined. In order to reduce the error, the signal noise ratio in the current signal is usually determined based on the absolute value of the first difference value and the ratio of the high-order signal. Comparing the signal noise ratio with the predetermined ratio threshold can obtain the comparison result of the signal noise ratio and the predetermined ratio threshold.

[0152] Suppose the predetermined ratio threshold is P1, then when the signal noise ratio , the high-order signal is taken as the output signal, and then the neutron flux detection result is determined.

[0153] In an embodiment, with reference to Figure 12 , after step S200, the detector signal processing method further comprises:

[0154] Step S510, when the high-order signal or the current signal is in the first linear overlap interval, determine that the signal noise ratio in the current signal is less than the predetermined ratio threshold based on the high-order signal and the current signal.

[0155] Step S520, determine a second difference value of the high-order signal and a lower limit signal value of the first linear overlap interval.

[0156] Step S530, determine a third difference value of an upper limit signal value and the lower limit signal value of the first linear overlap interval.

[0157] Step S540, determine a first weight of the current signal and a second weight of the high-order signal based on the second difference value and the third difference value.

[0158] Step S550, determining the first weighted sum of the current signal and the high-order signal based on the first weight and the second weight.

[0159] Step S560, determining the neutron flux detection result based on the first weighted sum.

[0160] It should be noted that the first linear overlap interval is a linear overlap interval of the high-order signal and the current signal, and the high-order signal and the current signal are simultaneously detected when the high-order signal or the current signal is in the first linear overlap interval. At this time, based on the high-order signal and the current signal, it can be determined that the signal noise ratio in the current signal is less than the predetermined ratio threshold, that is, the relative error of the measured neutron flux between the current mode and the high-order mode is small, and the error of the gamma ray noise is small.

[0161] Specifically, assuming that the current signal is , the high-order signal is , and the signal noise ratio is less than the predetermined ratio threshold P1.

[0162] It should be noted that the second difference value is the difference between the high-order signal and the lower limit signal value of the first linear overlap interval, and the third difference value 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 , the upper limit signal value of the first linear overlap interval is , the lower limit signal value is , the second difference value can be expressed as , and the third difference value can be expressed as .

[0163] After determining the second difference value and the third difference value, the first weight of the current signal and the second weight of the high-order signal are determined. The sum of the first weight and the second weight is 1. The first weight of the current signal can be expressed as:

[0164] ,

[0165] wherein, is the first weight, is the high-order signal. Then, the second weight of the high-order signal can be expressed as:

[0166] ,

[0167] wherein, is the second weight.

[0168] It should be noted that the first weight and the second weight can be set arbitrarily, as long as the second weight corresponding to the higher-order signal is smaller and the first weight of the current signal is larger when the higher-order signal is closer to the upper limit value of the first linear overlap interval.

[0169] It should be noted that after the first weight and the second weight are determined, the 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 represented as wherein, is the first weight, is the second weight, is the current signal, is the higher-order signal.

[0170] It should be noted that when the higher-order signal or the current signal is in the first linear overlap interval, the larger the higher-order signal, the smaller the second weight it occupies 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 interval, it is closer to the measurement range corresponding to the current signal, so the value determined based on the first weight and the second weight is more accurate, improving the accuracy of the neutron flux measurement result and realizing the smooth connection between the higher-order mode and the current mode.

[0171] In an embodiment, with reference to Figure 13 After step S100, the detector signal processing method further includes:

[0172] Step S610, determining a second linear overlap interval of the pulse signal and the higher-order signal.

[0173] Step S620, when the pulse signal or the higher-order signal is in the second linear overlap interval, determining a fourth difference value of the pulse signal and the lower limit signal value of the second linear overlap interval.

[0174] Step S630, determining a fifth difference value of the upper limit signal value and the lower limit signal value of the second linear overlap interval.

[0175] Step S640, determining a third weight of the higher-order signal and a fourth weight of the pulse signal based on the fourth difference value and the fifth difference value.

[0176] Step S650, determining a second weighted sum of the higher-order signal and the pulse signal based on the third weight and the fourth weight.

[0177] Step S660, determining a neutron flux detection result based on the second weighted sum.

[0178] It should be noted that the pulse mode is generally applicable to the measurement of low neutron flux level, while the high-order mode is applicable to the measurement of medium neutron flux level. When the neutron flux is near the critical value between the low neutron flux and the medium neutron flux, both the pulse signal and the high-order signal will be detected. The near critical value between the low neutron flux level and the medium neutron flux level can be considered as the second linear overlap interval.

[0179] The second linear overlap interval is a linear overlap interval between the pulse signal and the high-order signal, and in the second linear overlap interval, both the pulse signal and the high-order signal will be detected. There is a linear overlap interval and a saturation interval between the pulse signal and the high-order signal. Referring to Figure 2 , The second linear overlap interval is a linear overlap interval between the pulse signal and the high-order signal, and in the second linear overlap interval, both the pulse signal and the high-order signal will be detected. There is a linear overlap interval and a saturation interval between the pulse signal and the high-order signal. Referring to

[0180] When it is determined that the pulse signal or the high-order signal is in the second linear overlap interval, a fourth difference value between the pulse signal and the lower limit signal value of the second linear overlap interval is determined, and a fifth difference value between the upper limit signal value and the lower limit signal value of the second linear overlap interval is determined. Assuming that the second linear overlap interval is , the pulse signal is , the fourth difference value is , and the fifth difference value is .

[0181] After the fourth difference value and the fifth difference value are determined, a third weight of the high-order signal and a fourth weight of the pulse signal are determined. The sum of the third weight and the fourth weight is 1. The third weight of the high-order signal can be expressed as:

[0182] ,

[0183] wherein, is the third weight, is the pulse signal. Then the fourth weight of the pulse signal can be expressed as:

[0184] ,

[0185] wherein, is the fourth weight.

[0186] It should be noted that the third weight and the fourth weight can be set arbitrarily, as long as the fourth weight corresponding to the pulse signal is smaller when the pulse signal is closer to the upper limit signal value of the second linear overlap interval, and the third weight of the high-order signal is larger.

[0187] It should be noted that after the third weight and the fourth weight are determined, a second weighted sum of the high-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 represented as wherein, is the third weight, is the fourth weight, is the high-order signal, is the pulse signal.

[0188] It should be noted that when the pulse signal or the high-order signal is located in the second linear overlap interval, the greater the pulse signal, the smaller the fourth weight of the pulse signal in the output signal, and the greater the third weight of the high-order signal. Since the pulse signal is closer to the upper limit signal value of the second linear overlap interval, it is closer to the measurement range corresponding to the high-order signal, so the value determined based on the third weight and the fourth weight is more accurate, which improves the accuracy of the neutron flux measurement result and realizes the smooth connection between the pulse mode and the high-order mode.

[0189] It should be noted that the pulse signal, the high-order signal, and the current signal are processed in the embodiments of the present application to obtain a continuously changing output signal, i.e., the neutron flux signal F is:

[0190] ,

[0191] wherein, is the output signal, and the neutron flux detection result is determined based on . When the pulse signal is less than the lower limit signal value of the second linear overlap interval, the output signal is the pulse signal . When the pulse signal or the high-order signal is located in the second linear overlap interval , the output signal is wherein, is the third weight of the high-order signal , and is the fourth weight of the pulse signal . When the pulse signal is greater than the upper limit signal value of the second linear overlap interval or the high-order signal is located between the upper limit signal value of the second linear overlap interval and the lower limit signal value of the first linear overlap interval, the output signal is the high-order signal . When the high-order signal is located in a first linear overlapping interval or the current signal is located in a first linear overlapping interval , and a signal noise ratio is less than a predetermined ratio threshold , an output signal is , wherein, is a first weight of the current signal , and is a second weight of the high-order signal . When the current signal is greater than an upper limit signal value of the first linear overlapping interval , and the signal noise ratio is less than the predetermined ratio threshold , the output signal is the current signal . When the current signal is greater than the upper limit signal value of the first linear overlapping interval , and the signal noise ratio is greater than or equal to the predetermined ratio threshold , the output signal is the high-order signal .

[0192] The detector signal processing circuit 100 and the detector signal processing method provided by the embodiment of the present application integrate the pulse mode, the high-order mode and the Campbell mode together, can simultaneously process signals of the three modes, expand the measurement range of the detector 10, reduce the influence of gamma rays on neutron flux measurement through the setting of the pulse mode circuit 30 and the processing of related signals, improve the accuracy of the neutron flux detection result, and simultaneously collect signals of the three modes, calculate the neutron flux through weighted processing, so that there is no gear shifting, time delay, judgment and other gear switching processes in the stage of gradually increasing neutron flux, so that the signal is smoother.

[0193] The above describes the embodiments of the present application in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range of ordinary skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A detector signal processing circuit, characterized by, The application relates to a neutron flux detector. The detector is used for generating a detection signal. The pulse mode circuit is connected with the detector, and is used for pulse shaping the detection signal to obtain a pulse signal. The high-order mode circuit comprises a plurality of parallelly connected Campbell modules, the input end of the Campbell module is connected with the detector, and the Campbell module is used for converting the detection signal into a first-order signal. The current mode circuit is connected with the detector, and is used for converting the detection signal into a current signal. The control module is connected with the pulse mode circuit, the current mode circuit and the output end of each Campbell module respectively.

2. The circuit of claim 1, wherein, The control module is used for determining a high-order signal of the high-order mode circuit based on the first-order signal of each Campbell module. When the high-order signal is greater than the upper limit signal value of a first linear overlap interval, the control module determines a comparison result of the signal noise proportion in the current signal and a predetermined proportion threshold based on the high-order signal and the current signal.

3. The circuit of claim 2, wherein, The first linear overlap interval is a linear overlap interval of the high-order signal and the current signal. When the comparison result indicates that the signal noise proportion in the current signal is greater than or equal to the predetermined proportion threshold, the control module determines a neutron flux detection result based on the high-order signal. The application further relates to a neutron flux detector.

4. The circuit of claim 2, wherein, The preamplifier is connected with the detector, and the output end of the preamplifier is connected with the input end of the pulse mode circuit and the input end of each Campbell module. The Campbell module comprises: The delay unit is connected with the preamplifier. The band-pass filter is connected with the output end of the delay unit, and the input end of the band-pass filter is connected with the control module.

5. The circuit of claim 1, wherein, The pulse mode circuit comprises: The multi-stage amplifier is connected with the output end of the preamplifier. The comparator is connected with the multi-stage amplifier and a first voltage source. The pulse shaper is connected with the output end of the comparator and the control module. The current mode circuit comprises: The transformer is connected with the oscillation circuit. The voltage processing circuit is connected with the first output end of the transformer. The voltage feedback circuit comprises an error amplifier. The first input end of the error amplifier is connected with the output end of the voltage processing circuit. The second output end of the error amplifier is connected with a second voltage source. The output end of the error amplifier is connected with the input end of the transformer. A current sampling circuit, an input end of the current sampling circuit is connected with a second output end of the transformer, and an output end of the current sampling circuit is connected with the control module.

6. The circuit of claim 5, wherein, The voltage feedback circuit further comprises: A voltage sampling circuit, an input end of the voltage sampling circuit is connected with an output end of the voltage processing circuit, and an output end of the voltage sampling circuit is connected with a first input end of the error amplifier; A Darlington tube, an input end of the Darlington tube is connected with an output end of the error amplifier, and an output end of the Darlington tube is connected with an input end of the transformer.

7. A method of processing a detector signal, characterized by, The method is applied to a detector signal processing circuit, the detector signal processing circuit comprises a detector, a pulse mode circuit, a high-order mode circuit and a current mode circuit, the high-order mode circuit comprises a plurality of Campbell modules connected in parallel, each Campbell module, the pulse mode circuit and the high-order mode circuit are connected with the detector, and the method comprises: Determining a high-order signal of the high-order mode circuit based on a first-order signal of each Campbell module; Determining a first linear overlap interval of the high-order signal and a current signal of the current mode circuit; When the high-order signal is greater than an upper limit signal value of the first linear overlap interval, determining a comparison result of a signal noise proportion in the current signal and a predetermined proportion threshold based on the high-order signal and the current signal; In a case where the comparison result indicates that the signal noise proportion in the current signal is greater than or equal to the predetermined proportion threshold, determining a neutron flux detection result based on the high-order signal.

8. The method of processing a signal of a probe according to claim 7, characterized in that, The method further comprises: Determining a first difference value of the current signal and the high-order signal; Determining the signal noise proportion in the current signal based on a ratio of an absolute value of the first difference value and the high-order signal; Comparing the signal noise proportion with the predetermined proportion threshold to obtain the comparison result of the signal noise proportion and the predetermined proportion threshold.

9. The method of processing a signal of a probe according to claim 7, characterized in that, After determining the first linear overlap interval of the high-order signal and the current signal of the current mode circuit, the method further comprises: When the high-order signal or the current signal is located in the first linear overlap interval, determining that the signal noise proportion in the current signal is less than the predetermined proportion threshold based on the high-order signal and the current signal; Determining a second difference value of the high-order signal and a lower limit signal value of the first linear overlap interval; Determining a third difference value of an upper limit signal value and the lower limit signal value of the first linear overlap interval; Determining a first weight of the current signal and a second weight of the high-order signal based on the second difference value and the third difference value; Determining a first weighted sum of the current signal and the high-order signal based on the first weight and the second weight; Determining a neutron flux detection result based on the first weighted sum.

10. The method of processing a signal of a probe according to claim 7, characterized in that, After determining the high-order signal of the high-order mode circuit based on the first-order signal of each Campbell module, the method further comprises: determine a second linear overlap interval of the pulse signal and the high-order signal, the pulse signal being a pulse shaping result of a pulse mode circuit on a detection signal generated by the detector; determine a fourth difference value between the pulse signal and a lower limit signal value of the second linear overlap interval when the pulse signal or the high-order signal is in the second linear overlap interval; determine a fifth difference value between an upper limit signal value and the lower limit signal value of the second linear overlap interval; determine a third weight of the high-order signal and a fourth weight of the pulse signal based on the fourth difference value and the fifth difference value; determine a second weighted sum of the high-order signal and the pulse signal based on the third weight and the fourth weight; determine a neutron flux detection result based on the second weighted sum.

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