Detector signal processing circuit and detector signal processing method

Abstract

The invention provides a detector signal processing circuit and a detector signal processing method, which are applied to the field of nuclear technology application, and the detector signal processing circuit comprises a detector used for generating a detection signal; the pulse mode circuit is connected with the detector and is used for performing pulse shaping on the detection signal to obtain a pulse signal; the high-order mode circuit comprises a plurality of Campbell modules connected in parallel, the input ends of the Campbell modules are connected with the detector, and the Campbell modules are used for converting detection signals into first-order signals; the current mode circuit is connected with the detector; the current module is used for converting a 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. According to the embodiment of the invention, the accuracy of a neutron flux detection result can be improved, and the measurement range of the detector is expanded.

Description

Technical Field

[0001] The present 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 Art

[0002] The fission chamber detector is a neutron detector with a wide measurement range. It is widely used for neutron measurement in high gamma-ray environments because of 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 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 where the proportion of reactor gamma rays is relatively high, because the three modes have different degrees of suppression of gamma rays, the measurement results of the three modes at the same neutron flux level have large deviations. Therefore, the detector signal processing circuit in the related art can usually only process the pulse mode signal and mean square mode signal of the fission chamber detector, or can only process the current mode signal, and the measurement range is narrow. Summary of the invention

[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 neutron flux detection results and expand the measurement range of the detector.

[0004] In a first aspect, an embodiment of the present application provides a detector signal processing circuit, characterized in that it includes:

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

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

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

[0008] A current mode circuit, the 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, wherein the control module is respectively connected to the pulse mode circuit, the current mode circuit, and the output ends of each Campbell module; the control module is used to determine the 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 the first linear overlap interval, the comparison result of the signal-to-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; 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, the neutron flux detection result is determined based on the high-order signal.

[0010] According to the detector signal processing circuit provided in the first aspect of the embodiment of the present application, at least the following beneficial effects are achieved: 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 of 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 of gamma rays, the stronger the resolution of 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. In order 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, 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 the predetermined ratio threshold, 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, which can process signals of three modes at the same time, thereby expanding the measurement range of the detector. The setting of the high-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 the present application, it further includes:

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

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

[0014] A delay unit, wherein an input end of the delay unit is connected to the preamplifier;

[0015] A bandpass filter, wherein the input end of the bandpass filter is connected to the output end of the delay unit, the input end of the bandpass filter is connected to the control module, and the delay times corresponding to the delay units of the plurality of Campbell modules are arranged in an arithmetic progression.

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

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

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

[0019] A pulse shaper, wherein 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.

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

[0021] transformer;

[0022] an oscillating circuit connected to an input end of the transformer;

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

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

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

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

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

[0028] A Darlington tube, wherein the input end of the Darlington tube is connected to the output end of the error amplifier, and the output end of the Darlington tube is connected to the input end of the transformer.

[0029] In a second aspect, an embodiment of the present application provides a detector signal processing method, which is applied to a detector signal processing circuit, wherein the detector signal processing circuit includes a detector, a pulse mode circuit, a high-order mode circuit, and a current mode circuit, wherein the high-order mode circuit includes a plurality of Campbell modules connected in parallel, and each of the Campbell modules, the pulse mode circuit, and the high-order mode circuit are connected to the detector, and the method includes:

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

[0031] Determining a first linear overlap interval between the high-level signal and a current signal of the current mode circuit;

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

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

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

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

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

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

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

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

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

[0041] Determine a third difference between 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 and the third difference;

[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] A neutron flux detection result is determined 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 Campbell module, the method further includes:

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

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

[0048] Determine a fifth difference between 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 and the fifth difference;

[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] Based on the second weighted sum, a neutron flux detection result is determined.

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

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

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

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

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

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

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

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

[0062] Fig. 9 is a schematic diagram of a current mode circuit provided in an embodiment of the present application;

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

[0064] Fig.11 yes Fig.10 A flow chart of the comparison result of determining the signal-to-noise ratio with a predetermined ratio threshold in step S300;

[0065] Fig.12 is another flow chart of the detector signal processing method provided in an embodiment of the present application;

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

[0067] In the following description, specific details such as specific system structures, technologies, etc. are proposed for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the embodiments of the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from hindering the description of the embodiments of the present application.

[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 in the flowchart. The terms "first", "second", etc. in the specification, claims and the above 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 the references to "one embodiment" or "some embodiments" described in the specification of the embodiments of the present application mean that one or more embodiments of the embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Thus, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

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

[0071] The fission chamber detector is a neutron detector with a wide measurement range. It is widely used for neutron measurement in high gamma-ray environments because of 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 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 where the proportion of reactor gamma rays is relatively high, because the three modes have different degrees of suppression of gamma rays, the measurement results of the three modes at the same neutron flux level have large deviations. Therefore, the detector signal processing circuit in the related art can usually only process the pulse mode signal and 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 embodiments of the present application provide a detector signal processing circuit and a detector signal processing method. The detector signal processing circuit provided in the embodiments of the present application can improve the accuracy of neutron flux detection results and expand the measurement range of the detector.

[0073] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0074] Reference Figure 1 and Figure 4 An 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 used to generate a detection signal.

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

[0077] The pulse mode circuit 30 includes a plurality of Campbell modules 31 connected in parallel. The input end 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 ends of the pulse mode circuit 20 , the current mode circuit 40 , and each Campbell module 31 .

[0080] The control module 50 is specifically used for:

[0081] Based on the first order signals of the respective Campbell modules 31 , the high order signals of the pulse mode circuit 30 are 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-to-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] When the comparison result indicates that the signal-to-noise ratio in the current signal is greater than or equal to a predetermined ratio threshold, a 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 to measure the neutron flux outside the pile and generate a detection signal. When the neutron flux level is relatively low, the detection signal is an electrical signal in the form of a pulse, and the frequency of the pulse is proportional to the neutron flux level. As the neutron flux level increases, the pulse signals are superimposed on each other, and the detection signal is a pulsating DC signal with a certain frequency.

[0085] It should be noted that in pulse mode, the fission chamber detector can detect and count single neutron events, which is suitable for low neutron flux environments. The advantage of pulse mode is that it can effectively distinguish and count single 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 counts the pulses of the pulse signal to perform 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, which means the number of radiation detected per second is less than 10 5 .

[0086] Reference Figure 1 The control module 50 is a field programmable gate array (FPGA). The FPGA can process the pulse signal and calculate the counting rate by calculating the number of pulses per unit time. The counting rate is proportional to the neutron flux. In addition, the pulse signal is input to the FPGA through a buffer, which can reduce the attenuation and distortion 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, i.e., the high-order Campbell circuit, is implemented 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 the Campbell 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 the neutron flux by analyzing the fluctuation of the DC current, and 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 an environment with medium neutron flux, the control module 50 detects the first-order signal output by the Campbell module 31, and then 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 collection voltages of n Campbell modules 31 in the pulse mode circuit 30, that is, the first-order signals are V1, V2, ..., Vn, respectively, the collection voltage is converted into a variable Yn proportional to the neutron flux according to the following formula:

[0090]

[0091] Wherein, Yn is a high-order signal, n represents the number of Campbell modules 31 in the pulse mode circuit 30, m is a positive integer, which represents that the pulse mode circuit 30 includes m Campbell modules 31, and j is a positive integer in [1, m-2]. Vi represents the corresponding acquisition voltage of the i-th Campbell module 31 in the pulse mode circuit 30, that is, the first-order signal.

[0092] It should be noted that, since the dimensions of the three modes are different, the control module 50 will convert the current signal, high-order signal, and pulse signal into corresponding neutron flux signals for processing. Assuming that the current signal is Yi, and the neutron sensitivity corresponding to the current signal is Si, then the neutron flux signal corresponding to the current signal is Fi=Yi*Si. Assuming that the pulse signal is Ycps, and the neutron sensitivity corresponding to the pulse signal is Scps, then the neutron flux signal in the pulse mode is Fcps=Ycps*Scps. If the high-order signal is Yn, the neutron sensitivity corresponding to the high-order signal is Fh=Yn*Sh. The comparison between the high-order signal and the current signal is also based on the corresponding neutron flux signal.

[0093] In addition, when the neutron flux is near the critical value of the low neutron flux and the medium neutron flux, the control module 50 will detect the pulse signal and the high-order signal at the same time. At this time, the neutron flux statistics can be performed 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 fission rate range, that is, the high neutron flux environment. The current mode is suitable for situations where frequent pulses cannot be separated, and a continuous current is generated, so that the average value of the DC current from the detector 10 can be measured. 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 result determined based on the current mode has a large error.

[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 signal-to-noise ratio 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 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 ratio 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 used 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 region of the high-order signal and the current signal. There is a linear overlap region and a saturation region between the high-order signal and the current signal. Figure 2 ,[N l1 ,N h1 ] is the linear overlap region between the high-order signal and the current signal, i.e., the first linear overlap region. In the first linear overlap region, since the control module 50 detects both 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, while in the saturation region, although both the high-order signal and the current signal are detected at the same time, in order to achieve a smooth transition between the signals, the current signal is usually used as the output signal.

[0097] However, 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, when the high-order signal is greater than the upper limit signal value of the first linear overlap interval and the signal-to-noise ratio is greater than or equal to a predetermined ratio 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 signal-to-noise ratio 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 signal-to-noise ratio 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 in the embodiment of the present application is only applicable to fission chamber detectors.

[0100] It should be noted that the detector signal processing circuit 100 includes a pulse mode circuit 30, and the pulse mode circuit 30 adopts a 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 a stronger degree of suppression of gamma rays, and the greater the order of the pulse mode circuit 30, that is, the greater the number of Campbell modules 31, the stronger the degree of suppression of gamma rays, the stronger the resolution 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. In order 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 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 the predetermined ratio threshold, 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 100 of the embodiment of the present application includes a pulse mode circuit 20, a pulse mode circuit 30 and a current mode circuit 40, and can process signals of three modes at the same time, thereby 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.

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

[0102] It should be noted that the preamplifier 60 is used to amplify the detection signal output by the detector 10 to increase the strength of the detection signal, so as to facilitate the pulse mode circuit 20 and each Campbell module 31 to process the detection signal.

[0103] Reference Figure 3 , Figure 3The circuit diagram of the preamplifier 60 provided in the embodiment of the present application. The equivalent circuit corresponding to the detector and the cable includes a current source Id, an insulation resistor Rd and a distributed capacitor 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 and resistor Rf, capacitor Cf together constitute the circuit of the preamplifier 60. Among them, A1 can choose an integrated operational amplifier or a discrete amplifier built by a triode, C1 is a high-voltage capacitor, C1 is mainly used to isolate high voltage, and R2 is the matching resistor of the cable, which is usually 50 ohms (Ω). D1 and D2 are used for surge protection to reduce the current shock caused by high-voltage mutations that has a destructive effect on amplifier A1. Rf is the amplifier feedback resistor, and Cf is the amplifier feedback capacitor. Therefore, the transfer function of the loop can be determined as:

[0104]

[0105] Wherein, H(s) is the transfer function of the preamplifier 60, V(s) is the output voltage of the preamplifier 60, I(s) is the output current of the amplifier, s is the independent variable of the Laplace transform, usually expressed as a complex variable. C1 is the value of the capacitor C1, C0 is the value of the capacitor C0, τ1 is the time constant corresponding to the capacitor C1 and the resistor R1, and τ1=R1C1, τ f is the time constant corresponding to the capacitor Cf and the resistor Rf, and τ f =R f C f , R1 is the value of resistor R1, R f is the value of the resistor Rf.

[0106] In one embodiment, referring to Figure 4 The Campbell module 31 includes a delay unit and a bandpass filter, the input end of the delay unit is connected to the preamplifier 60, the output end of the delay unit is connected to the input end of the bandpass filter, the input end of the bandpass filter is connected to the control module 50, and the delay times corresponding to the delay units of multiple Campbell modules 31 are arranged in an arithmetic progression.

[0107] 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 arranged in an arithmetic progression, and the bandpass filters of the multiple Campbell modules 31 are the same.

[0108] The delay time of multiple delay units is an arithmetic progression, and the delay time 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 has nothing to do with the pulse width of the detection signal. Regardless of the pulse width of the detection signal, the pulse width of the output signal of the preamplifier 60 is always a fixed value. Assuming that the pulse width output by the preamplifier 60 is 100 microseconds, the time offset Td0 is 100 microseconds. T is the delay time difference between two adjacent delay units, which can be set to 1s, then the delay time of 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 a length of an arithmetic progression, or can be set as an all-pass filter. If the delay unit is an all-pass filter, the delay setting can be achieved by controlling the phase. The delay unit is set to facilitate the collection of first-order signals corresponding to different Campbell modules 31.

[0110] Reference Figure 5 , the delay unit is set as an all-pass filter, the input terminal Vin of the delay unit is connected to the preamplifier 60, the output terminal Vout of the delay unit is connected to the input terminal of the band-pass filter, and R37, R38, R39 and C21 together constitute an all-pass filter. The all-pass filter achieves phase adjustment by introducing phase delay without affecting the frequency characteristics of the signal. Therefore, the delay time of multiple delay units can be set in an arithmetic progression through the all-pass filter, and will not affect the signal input by the preamplifier 60.

[0111] The bandpass filter in Campbell module 31 is as follows Figure 6 As shown. Figure 6 In the bandpass filter shown, 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 a bandpass filter. In order to further enhance the clarity and recognition of the signal input to the bandpass filter, the embodiment of the present application adds a high-pass filter circuit and a first amplifier before the bandpass filter. Figure 6, Vin represents the detection signal after being processed by 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 recognition of the signal. In order to further enhance the clarity and recognition of the detection signal, U10, R6, and R7 constitute an amplifier for forward amplification of Vin. In addition, the embodiment of the present application is also provided with a second amplifier after the bandpass filter for amplifying the first-order signal. Figure 6 U19, R36 and R35 in the circuit constitute the second amplifier.

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

[0113] In one 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 increase the signal strength. 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. The comparator compares the pulse signal amplified by the multi-stage amplifier with the discrimination threshold voltage, that is, 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 required, and the value range of the discrimination threshold voltage is usually 0 to 5V.

[0116] Reference Figure 7 , Figure 7 A schematic diagram of the pulse mode circuit 20 provided in the embodiment of the present application. Vin is the detection signal after amplification by the preamplifier 60. U9, R4 and R5 constitute a primary amplifier circuit, U11, R8 and R9 constitute a secondary amplifier circuit, and the primary amplifier circuit and the secondary amplifier circuit together constitute Figure 1The multi-stage amplifier in. U14 is a comparator, which compares the pulse signal amplified by U11 with the discrimination threshold voltage, that is, 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, a resistor R34 and a capacitor C20. R34 and C20 are used to control the output pulse width of U2A, that is, 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 further enhance the clarity and recognition of the signal input to the bandpass filter, the embodiment of the present application is provided with a high-pass filter circuit before the bandpass filter. Figure 7 C2, R3, C9, R16, C10 and R17 together constitute a high-pass filter circuit.

[0117] Reference 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 FPGA.

[0118] In one embodiment, referring to Figure 1 and Figure 8 The current mode circuit 40 includes a transformer, an oscillating circuit 41, a voltage processing circuit 42, a voltage feedback circuit 43 and a current sampling circuit 44. The oscillating 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 used to provide a working voltage for the detector 10 after being processed by the voltage processing circuit 42.

[0120] The voltage feedback circuit 43 includes an error amplifier, a first input terminal of the error amplifier is connected to the output terminal of the voltage processing circuit 42, a second output terminal of the error amplifier is connected to the second voltage source, and the output terminal of the error amplifier is connected to the input terminal of the transformer. The error amplifier is used to compare the output voltage value of the voltage processing circuit 42 with the high voltage setting value, that is, the output voltage of the second voltage source, and then feed back 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 setting value.

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

[0122] In one embodiment, referring to Figure 1 and Figure 8 The voltage feedback circuit 43 also includes a voltage sampling circuit and a Darlington tube. The input end of the voltage sampling circuit is connected to the output end of the voltage processing circuit 42, and the output end of the voltage sampling circuit is connected to the first input end of the error amplifier. The input end of the Darlington tube is connected to the output end of the error amplifier, and the output end of the Darlington tube is connected to 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 can compare the output voltage of the voltage processing circuit 42 with the high voltage setting value, ie, the output voltage of the second voltage source.

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

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

[0126] Reference Figure 1 In the embodiment of the present disclosure, the output voltage V_Iout is converted into a digital signal through a voltage acquisition circuit, and the converted digital signal is processed through an FPGA.

[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, and the pulse mode circuit 30 adopts a 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 a stronger degree of suppression of gamma rays, and the more the order of the pulse mode circuit 30, that is, the number of Campbell modules 31, the stronger the degree of suppression of gamma rays, the stronger the resolution 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. In order 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 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 the predetermined ratio threshold, 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 100 of the embodiment of the present application includes a pulse mode circuit 20, a pulse mode circuit 30 and a current mode circuit 40, and can process signals of three modes at the same time, thereby 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.

[0128] In addition, the embodiment of the present application also provides a detector signal processing method, which is applied to a detector processing circuit. The detector signal processing circuit 100 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 a plurality of Campbell modules 31 connected in parallel. Each Campbell module 31, the pulse mode circuit 20, and the pulse mode circuit 30 are connected to the detector 10. The detector signal processing method includes but is not limited to the following steps:

[0129] Step S100: determining a high-order signal of a high-order mode circuit based on the first-order signals of each Campbell module.

[0130] Step S200: determining a first linear overlap interval between a high-order signal and a current signal of a current mode circuit.

[0131] Step S300 : when the high-order signal is greater than the upper limit signal value of the first linear overlap block, a comparison result between the signal-to-noise ratio in the current signal and a predetermined ratio threshold is determined based on the high-order signal and the current signal.

[0132] Step S400: When the comparison result indicates that the signal-to-noise ratio in the current signal is greater than or equal to a predetermined ratio threshold, determine a neutron flux detection result based on the high-order signal.

[0133] It should be noted that the first-order signal is a signal obtained by processing the detection signal of the detector 10 by each Campbell.

[0134] 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 of n Campbell modules 31 in the pulse mode circuit 30, that is, the first-order signals are V1, V2, ..., Vn respectively, the collected voltage is converted into a variable Yn proportional to the neutron flux according to the following formula:

[0135]

[0136] Wherein, Yn is a high-order signal, n represents the number of Campbell modules 31 in the pulse mode circuit 30, m is a positive integer, which represents that the pulse mode circuit 30 includes m Campbell modules 31, and j is a positive integer in [1, m-2]. Vi represents the corresponding acquisition voltage of the i-th Campbell module 31 in the pulse mode circuit 30, that is, 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 Yi, and the neutron sensitivity corresponding to the current signal is Si, then the neutron flux signal corresponding to the current signal is Fi=Yi*Si. Assuming that the pulse signal is Ycps, and the neutron sensitivity corresponding to the pulse signal is Scps, then the neutron flux signal in the pulse mode is Fcps=Ycps*Scps. If the high-order signal is Yn, the neutron sensitivity corresponding to the high-order signal is Fh=Yn*Sh. The comparison between the high-order signal and the current signal is also based on the corresponding neutron flux signal.

[0138] The first linear overlap interval is a linear overlap region between the high-order signal and the current signal of the current mode circuit 40. In addition, the first linear overlap interval is also determined 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. Figure 2 ,[N l1 ,N h1 ] is the linear overlap region between the high-order signal and the current signal, i.e., the first linear overlap region. In the first linear overlap region, since the control module 50 detects both 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, while in the saturation region, although both the high-order signal and the current signal are detected at the same time, in order to achieve a smooth transition between the signals, the current signal is usually used as the output signal.

[0140] It should be noted that the signal-to-noise ratio refers to the ratio of the signal noise caused by the γ signal to the current signal.

[0141] The current mode is mainly used in the high fission rate range, that is, in the high neutron flux environment. The current mode is suitable for situations where frequent pulses cannot be separated, and a continuous current is generated, so that the average value of the DC current from the detector 10 can be measured. 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 result determined based on the current mode has a large error.

[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 signal-to-noise ratio 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 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 ratio 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 used 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 signal-to-noise ratio 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 signal-to-noise ratio 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 in the embodiment 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, and the pulse mode circuit 30 adopts a 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 a stronger degree of suppression of gamma rays, and the greater the order of the pulse mode circuit 30, that is, the greater the number of Campbell modules 31, the stronger the degree of suppression of gamma rays, the stronger the resolution 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. In order 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 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 the predetermined ratio threshold, 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 100 of the embodiment of the present application includes a pulse mode circuit 20, a pulse mode circuit 30 and a current mode circuit 40, and can process signals of three modes at the same time, thereby 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.

[0146] In one embodiment, referring to Fig.11 Step S300 includes but is not limited to the following steps:

[0147] Step S310: determine a first difference between the current signal and the high-order signal.

[0148] 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 high-order signal.

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

[0150] It should be noted that the first difference refers to the ratio between the current signal and the high-order signal. The signal-to-noise ratio in the current signal can be expressed as: Wherein, Fi is the current signal, Fh is the high-order signal, and Fi-Fh is the first difference between 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 of a certain neutron flux, the more gamma dose there is, the larger the current signal is, and the larger the first difference between the current signal and the high-order signal is, and it is a positive value. Therefore, based on the ratio of the first difference and the high-order signal, the signal-to-noise ratio in the current signal can be determined. However, in order to reduce errors, the signal-to-noise ratio in the current signal is usually determined based on the absolute value of the first difference and the ratio of the high-order signal. By comparing the signal-to-noise ratio with the predetermined ratio threshold, a comparison result of the signal-to-noise ratio and the predetermined ratio threshold can be obtained.

[0152] Assuming the predetermined ratio threshold is P1, when the signal-to-noise ratio When the neutron flux is detected, the high-order signal is used as the output signal to determine the neutron flux detection result.

[0153] In one embodiment, referring to Fig.12 After step S200, the detector signal processing method further includes:

[0154] Step S510: When the high-order signal or the current signal is located in the first linear overlap interval, based on the high-order signal and the current signal, determine whether the signal-to-noise ratio in the current signal is less than a predetermined ratio threshold.

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

[0156] Step S530: Determine a third difference between the 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 and the third difference.

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

[0159] Step S560: Determine a 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 area of ​​the high-order signal and the current signal. When the high-order signal or the current signal is in the first linear overlap interval, the high-order signal and the current signal are detected at the same time. 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 neutron flux measured 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 Fi and the high-order signal is Fh, then determine the signal-to-noise ratio Less than the predetermined proportion threshold is P1.

[0162] It should be noted that the second difference is the difference between the high-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. 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.

[0163] After determining the second difference and the third difference, determine the first weight of the current signal and the second weight of the high-order signal. 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] Where w1 is the first weight and Fh is the high-order signal. Then, the second weight of the high-order signal can be expressed as:

[0166]

[0167] Among them, w2 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 high-order signal is smaller and the first weight of the current signal is larger when the high-order signal is closer to the signal upper limit value of the first linear overlap interval.

[0169] It should be noted that after determining the first weight and the second weight, the first weighted sum of the current signal and the high-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 high-order signal.

[0170] It should be noted that when the high-order signal or the current signal is in the first linear overlap interval, the larger the high-order signal is, the smaller its second weight in the output signal is, and the larger the first weight of the current signal is. Since the high-order signal is closer to the upper limit signal value of the first linear overlap interval 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 achieves a smooth connection between the high-order mode and the current mode.

[0171] In one embodiment, referring to Fig.13 , after step S100, the detector signal processing method further includes:

[0172] Step S610: determine a second linear overlapping interval of the pulse signal and the high-order signal.

[0173] Step S620: When the pulse signal or the high-order signal is located in the second linear overlap interval, determine a fourth difference between the pulse signal and the lower limit signal value of the second linear overlap interval.

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

[0175] Step S640: Determine a third weight of the high-order signal and a fourth weight of the pulse signal based on the fourth difference and the fifth difference.

[0176] Step S650: Determine a second weighted sum of the high-order signal and the pulse signal based on the third weight and the fourth weight.

[0177] Step S660: Determine the neutron flux detection result based on the second weighted sum.

[0178] It should be noted that the pulse mode is usually suitable for measuring low neutron flux levels, while the high-order mode is suitable for measuring medium neutron flux levels. When the neutron flux is near the critical value of low neutron flux and medium neutron flux, pulse signals and high-order signals will be detected at the same time. The critical value of low neutron flux level and medium neutron flux level can be considered as the second linear overlap interval.

[0179] The second linear overlap interval is the linear overlap area of ​​the pulse signal and the high-order signal. In the second linear overlap interval, the pulse signal and the high-order signal are detected at the same time. There is a linear overlap area and a saturation area between the pulse signal and the high-order signal. Figure 2, [Nl2, Nh2] is the linear overlap region between the pulse signal and the high-order signal, i.e., the second linear overlap region. In the second linear overlap region, since the high-order signal and the pulse signal are detected at the same time, the pulse signal and the high-order signal need to be connected, while in the saturation region, although the pulse signal and the high-order signal are detected at the same time, in order to achieve a smooth transition between the signals, the high-order signal is usually used as the output signal.

[0180] When it is determined that the pulse signal or the high-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, and a fifth difference 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 [Nl2, Nh2] and the pulse signal is Fcps, then the fourth difference is Fcps-Nl2, and the fifth difference is Nh2-Nl2.

[0181] After determining the fourth difference and the fifth difference, determine the third weight of the high-order signal and the fourth weight of the pulse signal. 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, w3 is the third weight, and Fcps is the pulse signal. Then the fourth weight of the pulse signal can be expressed as:

[0184]

[0185] Among them, w4 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 and the third weight of the high-order signal is larger when the pulse signal is closer to the signal upper limit value of the second linear overlap interval.

[0187] It should be noted that after determining the third weight and the fourth weight, the 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 expressed as w4*Fcps+w3*Fh, where w3 is the third weight, w4 is the fourth weight, Fh is the high-order signal, and Fcps is the pulse signal.

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

[0189] It should be noted that the embodiment of the present application processes the pulse signal, the high-order signal, and the current signal to obtain a continuously changing output signal, that is, the neutron flux signal F is:

[0190]

[0191] Wherein, 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 high-order signal Fh is located in the second linear overlap interval [Nl2, Nh2]. The output signal F is w4*Fcps+w3*Fh, wherein w3 is the third weight of the high-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 the high-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 high-order signal Fh. When the high-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-to-noise ratio 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 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 it is greater than or equal to the predetermined proportion threshold P1, the output signal F is a high-order signal Fh.

[0192] The detector signal processing circuit 100 and the detector signal processing method provided in the embodiment of the present application integrate the pulse mode, the high-order mode and the Campbell mode, and can process the signals of the three modes at the same time, thereby 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 the neutron flux measurement, improve the accuracy of the neutron flux detection results, and collect the signals of the three modes at the same time, and calculate the neutron flux through weighted processing. Therefore, in the stage when the neutron flux gradually increases, there is no gear switching process such as gear shifting, delay, and judgment, thereby making the signal smoother.

[0193] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field 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 in that: include: A detector, the detector being used to generate a detection signal; A pulse mode circuit, the pulse mode circuit is connected to the detector, and the pulse mode circuit is used to perform pulse shaping on the detection signal to obtain a pulse signal; A high-order mode circuit, the high-order mode circuit comprising a plurality of Campbell modules connected in parallel, the input end of the Campbell module being connected to the detector, the Campbell module being used to convert the detection signal into a first-order signal; A current mode circuit, the 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, wherein the control module is respectively connected to the pulse mode circuit, the current mode circuit, and the output ends of each Campbell module; the control module is used to determine the 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 the first linear overlap interval, the comparison result of the signal-to-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; 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, the neutron flux detection result is determined based on the high-order signal.

2. The circuit according to claim 1, characterized in that Also includes: A preamplifier, wherein the input end of the preamplifier is connected to the detector, and the output end of the preamplifier is connected to the input end of the pulse mode circuit and the input end of each Campbell module.

3. The circuit according to claim 2, characterized in that The Campbell modules include: A delay unit, wherein an input end of the delay unit is connected to the preamplifier; A bandpass filter, wherein the input end of the bandpass filter is connected to the output end of the delay unit, the input end of the bandpass filter is connected to the control module, and the delay times corresponding to the delay units of the plurality of Campbell modules are arranged in an arithmetic progression.

4. The circuit according to claim 2, characterized in that The pulse mode circuit comprises: A multi-stage amplifier, wherein an input end of the multi-stage amplifier is connected to an output end of the preamplifier; A comparator, wherein a first input terminal of the comparator is connected to the multi-stage amplifier, and a second input terminal of the comparator is connected to a first voltage source; A pulse shaper, wherein 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.

5. The circuit according to claim 1, characterized in that The current mode circuit comprises: transformer; an oscillating circuit connected to an input end of the transformer; a voltage processing circuit, wherein an input end of the voltage processing circuit is connected to the first output end of the transformer, and an output end of the voltage processing circuit is connected to the detector; A voltage feedback circuit, the voltage feedback circuit comprising an error amplifier, a first input terminal of the error amplifier is connected to an output terminal of the voltage processing circuit, a second output terminal of the error amplifier is connected to a second voltage source, and an output terminal of the error amplifier is connected to an input terminal of the transformer; A current sampling circuit, wherein an input end of the current sampling circuit is connected to the second output end of the transformer, and an output end of the current sampling circuit is connected to the control module.

6. The circuit according to claim 1, characterized in that The voltage feedback circuit further includes: a voltage sampling circuit, wherein an input end of the voltage sampling circuit is connected to an output end of the voltage processing circuit, and an output end of the voltage sampling circuit is connected to a first input end of the error amplifier; A Darlington tube, wherein the input end of the Darlington tube is connected to the output end of the error amplifier, and the output end of the Darlington tube is connected to the input end of the transformer.

7. A detector signal processing method, characterized in that: Applied to a detector signal processing circuit, the detector signal processing circuit includes a detector, a pulse mode circuit, a high-order mode circuit and a current mode circuit, the high-order mode circuit includes a plurality of Campbell modules connected in parallel, each of the Campbell modules, the pulse mode circuit and the high-order mode circuit is connected to the detector, and the method includes: determining a high-order signal of the high-order mode circuit based on the first-order signals of each of the Campbell modules; Determining a first linear overlap interval between the high-level signal and a current signal of the current mode circuit; When the high-order signal is greater than the upper limit signal value of the first linear overlap block, determining a comparison result of a signal-to-noise ratio in the current signal and a predetermined ratio threshold based on the high-order signal and the current signal; When the comparison result indicates that the signal-to-noise ratio in the current signal is greater than or equal to a predetermined ratio threshold, a neutron flux detection result is determined based on the high-order signal.

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

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

10. The detector signal processing method according to claim 7, characterized in that: After determining the high-order signal of the high-order mode circuit based on the first-order signals of each Campbell module, the method further includes: determining a second linear overlapping interval of the pulse signal and the high-order signal; When the pulse signal or the high-order signal is located in the second linear overlap interval, determining a fourth difference between the pulse signal and a lower limit signal value of the second linear overlap interval; Determine a fifth difference between the upper limit signal value and the lower limit signal value of the second linear overlap interval; Determining a third weight of the high-order signal and a fourth weight of the pulse signal based on the fourth difference and the fifth difference; Determining a second weighted sum of the high-order signal and the pulse signal based on the third weight and the fourth weight; Based on the second weighted sum, a neutron flux detection result is determined.

Images