Nuclear pulse amplitude extraction method based on parameter identification and nuclear pulse analysis system
By correcting baseline drift using filtering and shaping the nuclear pulse signal using joint filtering, and decomposing the accumulated pulse using a parameter identification model, the problem of decreased energy spectrum accuracy in nuclear pulse analysis systems at high count rates was solved, achieving nuclear pulse analysis with high energy resolution and high count rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2024-11-13
- Publication Date
- 2026-06-09
AI Technical Summary
Existing nuclear pulse analysis systems are susceptible to baseline drift and pulse accumulation at high count rates, leading to decreased energy spectrum accuracy and insufficient energy resolution and count rate.
A parameter identification-based nuclear pulse amplitude extraction method is adopted. The baseline drift is corrected by filtering, the nuclear pulse signal is shaped by joint filtering, the stacked pulse is decomposed by parameter identification model, the nuclear pulse amplitude is extracted, and a high-precision energy spectrum is generated.
It improves the energy resolution and count rate of the nuclear pulse analysis system and solves the problem of decreased energy spectrum accuracy caused by baseline drift and pulse accumulation.
Smart Images
Figure CN119577407B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of digital signal processing technology, specifically providing a method for extracting nuclear pulse amplitude based on parameter identification and a digital multichannel pulse analysis system. Background Technology
[0002] In fields such as nuclear physics research, nuclear energy applications, and nuclear radiation detection, the accurate analysis and processing of nuclear pulse signals are crucial. Nuclear pulse signals contain rich information about nuclear reactions. By accurately capturing, analyzing, and processing these signals, important parameters related to nuclear reaction processes, such as energy distribution and reaction type, can be obtained. Therefore, developing efficient and accurate nuclear pulse analysis systems has always been a research hotspot in this field.
[0003] Digital filtering and shaping of nuclear signals is a key technology for digital nuclear energy spectrum measurement systems. Previously, during spectral measurements, spectral accuracy was often affected by pulse buildup, ballistic defects, baseline drift, and noise, with these effects being particularly severe at high count rates. Currently, several nuclear pulse analysis systems have been proposed, but most suffer from low energy resolution and poor count rates. Therefore, developing a high-resolution, high-count-rate digital multichannel nuclear pulse analysis system is of great significance for advancing nuclear physics research, nuclear energy applications, and nuclear radiation detection. Summary of the Invention
[0004] The purpose of this invention is to provide a nuclear pulse amplitude extraction method and a digital multichannel pulse analysis system based on parameter identification, to solve the problem of decreased energy spectrum accuracy caused by baseline drift and pulse accumulation discarding in nuclear pulse signals, thereby improving the energy resolution and count rate of nuclear pulse energy spectra. This invention enables accurate acquisition and processing of nuclear pulse signals. First, a filtering method is used to process the original sampled sequence signal to reduce the impact of baseline drift. Then, a parameter identification model is used to identify the parameters of the accumulated pulses processed by the joint filtering method and extract their amplitudes, generating a high-precision spectrum. This improves the system's energy resolution and count rate, providing strong technical support for nuclear physics research, nuclear energy applications, and nuclear radiation detection.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A method for extracting nuclear pulse amplitude based on parameter identification, characterized by comprising the following steps:
[0007] Step 1. Acquire the electrical signal from the digital nuclear energy spectrum measurement system, and obtain a negative exponentially decaying pulse signal through a preamplifier circuit.
[0008]
[0009] Step 2. Apply negative exponentially decaying pulse signals The baseline is estimated using a filtering method to obtain the baseline value. And based on baseline values After drift correction, a negative exponentially decaying signal V is obtained. i (t);
[0010] Step 3. Set the filtering time parameter t a With t b The negative exponentially decaying signal V is transformed using a joint filtering shaping method. i (t) is converted into a triangular pulse signal V o1 (t) and trapezoidal pulse signal V o2 (t);
[0011] Step 4. Search for the triangular pulse signal V o1 For all triangular peak times in (t), for any triangular peak time t o1max The corresponding triangular pulse peak value V is obtained. o1 (t o1max ), the half-height amplitude V of the falling edge of the triangular pulse o1 (t o1max +(n b -n a ) / 2), and at the same time, the trapezoidal pulse peak value V is obtained by searching. o2 (t o1max ), trapezoidal pulse center amplitude V o2 (t o1max +(n b -n a ) / 2);
[0012] Step 5. Establish the stacking discrimination condition, for any triangular peak time t o1max If the accumulation criterion is met, then the signal V is determined to be a negative exponentially decaying signal. i (t) represents the stacked pulse signal, and the amplitude coefficient A of the stacked pulse signal is obtained by the parameter identification model. i Otherwise, obtain the trapezoidal pulse peak value V. o2 (t o1max ) as the amplitude of the trapezoidal pulse;
[0013] Step 6. Generate a nuclear pulse energy spectrum based on the amplitude coefficients of all extracted trapezoidal pulses and the stacked pulse signal to complete the nuclear pulse signal amplitude extraction.
[0014] Furthermore, in step 1, the negative exponentially decaying pulse signal Specifically, it is expressed as follows:
[0015]
[0016] Where t represents the discrete-time variable, and i represents the sequence number of the nuclear pulse signal. Let represent the negatively exponentially decaying pulse signal at time t, w(t) represent the noise signal at time t, and u(t) represent the unit step signal. A i T represents the amplitude coefficient of the i-th nuclear pulse signal. i Let τ represent the occurrence time of the i-th nuclear pulse signal, τ represent the attenuation coefficient, and N represent the total number of nuclear pulse signals.
[0017] Furthermore, in step 2, the baseline value Specifically, it is expressed as follows:
[0018]
[0019] Among them, B i This represents the i-th baseline sample value. and represents the i-th and (i-1)-th baseline values after filtering, respectively, and k represents the weight calculation factor.
[0020] Furthermore, in step 2, drift correction is specifically expressed as:
[0021]
[0022] Among them, V i (t) represents the negative exponentially decaying pulse signal after drift correction.
[0023] Furthermore, in step 3, the triangular pulse signal V o1 (t) is represented as:
[0024]
[0025] in, n c =2*n a , τ is the attenuation coefficient, T s Indicates the sampling period.
[0026] Furthermore, in step 3, the trapezoidal pulse signal V o2 (t) is represented as:
[0027]
[0028] in, n d =n a +n b , τ is the attenuation coefficient, T s Indicates the sampling period.
[0029] Furthermore, in step 5, the parameter identification model identifies the amplitude coefficient A of the stacked pulse signal. i The specific process is as follows: the accumulated pulse signal is fed into the parameter identification model to obtain the attenuation coefficient τ and amplitude coefficient A of the accumulated pulse signal. i With time T i And generate parameters (attenuation coefficient τ, amplitude coefficient A) i With time T i The trapezoidal pulse signal obtained Calculate the amplitude of the trapezoidal pulse With trapezoidal pulse amplitude V o2 (t o1max The difference E is calculated, and when the absolute value of the difference E is less than a preset threshold, the recognition ends and the corresponding amplitude coefficient A is output. i Otherwise, continue iterating.
[0030] Furthermore, in step 5, the stacking discrimination condition is that any of the following conditions are met:
[0031] First criterion: V o1 (t o1max )≠2*V o1 (t o1max +(n b -n a ) / 2),
[0032] First criterion: V o2 (t o1max )≠V o2 (t o1max +(n b -n a ) / 2).
[0033] Based on the above-mentioned parameter identification-based nuclear pulse shaping amplitude extraction method, the present invention also provides a digital multichannel pulse analysis system, wherein the digital multichannel pulse analysis system for processing nuclear pulse signals includes:
[0034] The digital baseline estimation module is used to implement filtering and drift correction. It estimates the baseline using filtering and performs drift correction on the negative exponential decay signal based on the baseline value.
[0035] The digital filtering shaping module is used to establish a dual-channel joint filtering shaping method, which converts the negative exponential decay signal after drift correction into a triangular pulse signal and a trapezoidal pulse signal.
[0036] The pulse amplitude extraction module is used to search for the peak time of the triangular pulse signal and extract the corresponding amplitude parameters.
[0037] The pulse accumulation judgment module is used to establish accumulation judgment conditions and judge the accumulated pulse signal based on the amplitude parameter;
[0038] The pulse accumulation parameter identification module is used to establish a parameter identification model and identify the amplitude coefficient of the accumulated pulse signal through the parameter identification model.
[0039] The digital energy spectrum generation module is used to generate nuclear pulse energy spectra based on the amplitude of the trapezoidal pulse and the amplitude coefficient of the stacked pulse signal.
[0040] Based on the above technical solution, the beneficial effects of the present invention are as follows:
[0041] This invention provides a method for extracting the amplitude of nuclear pulse signals based on parameter identification and a nuclear pulse analysis system. First, the baseline is estimated by using a filtering method on the sampled signal to complete drift correction. Then, a joint filtering shaping method is established to determine the pulse generation time and the generation of pulse accumulation, and to extract the effective pulse amplitude of normal, non-accumulated nuclear pulse signals. Finally, the accumulated pulses are decomposed and parameters are extracted by a parameter identification model to obtain more effective pulse amplitudes. In summary, this invention solves the problem of decreased energy spectrum accuracy caused by baseline drift and pulse accumulation discarding of nuclear pulse signals, and improves the energy resolution and count rate of the system. Attached Figure Description
[0042] Figure 1 This is a flowchart illustrating the nuclear pulse signal amplitude extraction method provided in this embodiment of the invention.
[0043] Figure 2 This is a schematic diagram of the structure of the digital multichannel pulse analysis system provided in an embodiment of the present invention.
[0044] Figure 3 This is a schematic diagram of baseline correction provided in an embodiment of the present invention.
[0045] Figure 4 The diagram shows the principle of trapezoidal filtering and triangular filtering provided in the embodiments of the present invention.
[0046] Figure 5 This is a schematic diagram of trapezoidal filtering and triangular filtering provided in the embodiments of the present invention.
[0047] Figure 6 This is a schematic diagram of the parameter identification principle provided in the embodiments of the present invention.
[0048] Figure 7 This is a comparison diagram of the nuclear pulse energy spectrum generated by the parameter identification-based nuclear pulse signal amplitude extraction method and the trapezoidal filtering method provided in the embodiments of the present invention. Detailed Implementation
[0049] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are only for explaining the invention and are not intended to limit the invention.
[0050] This embodiment provides a method for extracting the amplitude of nuclear pulse signals based on parameter identification, the process of which is as follows: Figure 1 As shown, the specific steps include:
[0051] Step 1. Acquire the probe electrical signal of the digital nuclear energy spectrum measurement system, and obtain a negative exponentially decaying pulse signal through a preamplifier circuit. Specifically, it is expressed as follows:
[0052]
[0053] Where t represents the discrete-time variable, and i represents the sequence number of the nuclear pulse signal. Let represent the negatively exponentially decaying pulse signal at time t, w(t) represent the noise signal at time t, and u(t) represent the unit step signal. A i T represents the amplitude coefficient of the i-th nuclear pulse signal. i The time of occurrence of the i-th nuclear pulse signal is represented by τ, the attenuation coefficient is represented by N, and the total number of nuclear pulse signals is represented by N.
[0054] Step 2. Apply negative exponentially decaying pulse signals The baseline is estimated using a filtering method to obtain the baseline value. And based on baseline values For negative exponentially decaying pulse signals Complete drift correction;
[0055] The baseline value Specifically, it is expressed as follows:
[0056]
[0057] Among them, B i This represents the i-th baseline sample value. and These represent the i-th and (i-1)-th baseline values after filtering, respectively, and k represents the weight calculation factor;
[0058] The drift correction is expressed as:
[0059]
[0060] Among them, V i (t) represents the negative exponentially decaying pulse signal after drift correction;
[0061] Step 3. Set the filtering time parameter t a With tb The negative exponentially decaying signal V is transformed using a joint filtering shaping method. i (t) is converted into a triangular pulse signal V o1 (t) and trapezoidal pulse signal V o2 (t);
[0062] The triangular pulse signal V o1 (t) is represented as:
[0063]
[0064] in, n c =2*n a , τ is the attenuation coefficient, T s Indicates the sampling period;
[0065] The trapezoidal pulse signal V o2 (t) is represented as:
[0066]
[0067] in, n d =n a +n b , τ is the attenuation coefficient, T s Indicates the sampling period;
[0068] Step 4. Search for the triangular pulse signal V o1 For all triangular peak times in (t), for any triangular peak time t o1max The corresponding triangular pulse peak value V is obtained. o1 (t o1max ), the half-height amplitude V of the falling edge of the triangular pulse o1 (t o1max +(n b -n a ) / 2), and at the same time, the trapezoidal pulse peak value V is obtained by searching. o2 (t o1max ), trapezoidal pulse center amplitude V o2 (t o1max +(n b -n a ) / 2);
[0069] Step 5. Establish the stacking discrimination condition, for any triangular peak time t o1max If the accumulation criterion is met, then the signal V is determined to be a negative exponentially decaying signal. i (t) represents the stacked pulse signal, and the amplitude coefficient A of the stacked pulse signal is obtained by the parameter identification model. iOtherwise, obtain the trapezoidal pulse peak value V. o2 (t o1max ) as the amplitude of the trapezoidal pulse;
[0070] The parameter identification model identifies the amplitude coefficient A of the stacked pulse signal. i The specific process is as follows: The triangular pulse signal V... o1 (t), trapezoidal pulse signal V o2 (t) and the corresponding triangular peak time t o1max The attenuation coefficient τ and amplitude coefficient A of the accumulated pulse signal are obtained by inputting them into the parameter recognition model. i With time T i And generate parameters (attenuation coefficient τ, amplitude coefficient A) i With time T i The trapezoidal pulse signal obtained Calculate the amplitude of the trapezoidal pulse With trapezoidal pulse amplitude V o2 (t o1max The difference E is calculated, and when the absolute value of the difference E is less than a preset threshold, the recognition ends and the corresponding amplitude coefficient A is output. i Otherwise, continue iterating;
[0071] The stacking discrimination condition is that any of the following conditions are met:
[0072] First criterion: V o1 (t o1max )≠2*V o1 (t o1max +(n b -n a ) / 2)
[0073] First criterion: V o2 (t o1max )≠V o2 (t o1max +(n b -n a ) / 2)
[0074] Step 6. Generate a nuclear pulse energy spectrum based on the amplitude coefficients of all extracted trapezoidal pulses and the stacked pulse signal to complete the nuclear pulse signal amplitude extraction.
[0075] This embodiment also provides a digital multichannel pulse analysis system, such as... Figure 2 As shown, the digital multichannel pulse analysis system used to implement the above-described parameter identification-based nuclear pulse shaping amplitude extraction method includes:
[0076] The digital baseline estimation module is used to implement filtering and drift correction. It estimates the baseline using filtering and performs drift correction on the negative exponential decay signal based on the baseline value.
[0077] The digital filtering shaping module is used to establish a dual-channel joint filtering shaping method, which converts the negative exponential decay signal after drift correction into a triangular pulse signal and a trapezoidal pulse signal.
[0078] The pulse amplitude extraction module is used to search for the peak time of the triangular pulse signal and extract the corresponding amplitude parameters.
[0079] The pulse accumulation judgment module is used to establish accumulation judgment conditions and judge the accumulated pulse signal based on the amplitude parameter;
[0080] The pulse accumulation parameter identification module is used to establish a parameter identification model and identify the amplitude coefficient of the accumulated pulse signal through the parameter identification model.
[0081] The digital energy spectrum generation module is used to generate nuclear pulse energy spectra based on the amplitude of the trapezoidal pulse and the amplitude coefficient of the stacked pulse signal.
[0082] The following description, using simulation tests of the digital nuclear energy spectrum measurement system, further illustrates the implementation example.
[0083] The simulation signal used in this embodiment is a pulse sequence generated based on the Monte Carlo method. Its energy spectrum is in good agreement with the actual instrument measurement results. This is used as the input signal for simulation testing to verify the good effect of the present invention in handling pulse accumulation. The specific steps are as follows:
[0084] Step 1. Generate a negative exponentially decaying pulse signal with a known amplitude based on Monte Carlo simulation, and input it as the input signal to the digital multichannel pulse analysis system, such as... Figure 2 As shown;
[0085] Step 2. Estimate the baseline using a filtering method on the sampled signal, with a weighting factor k = 3, as shown below. Figure 3 As shown, baseline correction is completed;
[0086] Step 3. Set the time parameter t for trapezoidal forming. a =10T s t b =20T s The time parameter t for triangular forming a =10T s t b =20T s The pulse signal is combined and shaped to complete the signal conversion, such as... Figure 4 , Figure 5 As shown, Figure 4 (a) shows the schematic diagram of a trapezoidal filter. Figure 4 (b) Schematic diagram of the triangular filter principle. Figure 5 These are schematic diagrams of trapezoidal filtering and triangular filtering;
[0087] Step 4. Search for the triangular pulse signal V o1 For all triangular peak times in (t), for any triangular peak time t o1max The corresponding triangular pulse peak value V is obtained. o1 (t o1max ), the half-height amplitude V of the falling edge of the triangular pulse o1 (t o1max +(n b -n a ) / 2), and at the same time, the trapezoidal pulse peak value V is obtained by searching. o2 (t o1max ), trapezoidal pulse center amplitude V o2 (t o1max +(n b -n a ) / 2);
[0088] Step 5. Compare the amplitude at each peak moment to determine the accumulation situation. If there is no accumulation, obtain the trapezoidal pulse peak value V. o2 (t o1max When there is accumulation, the accumulated pulses are sent to the parameter identification model, and the threshold is set to the trapezoidal pulse peak value V. o2 (t o1max 5% of the result yields the amplitude coefficient for stacked pulse separation, such as Figure 6 The diagram shown is a schematic diagram of the parameter identification principle.
[0089] Step 6. Generate a nuclear pulse energy spectrum based on the extracted amplitudes of all trapezoidal pulses and stacked pulse signals, such as... Figure 7 The figure shows a comparison of the nuclear pulse energy spectra generated by the parameter identification-based nuclear pulse signal amplitude extraction method and the trapezoidal filtering method. As can be seen from the figure, the parameter identification-based nuclear pulse signal amplitude extraction method in this invention effectively improves the count value of the spectrum, which is helpful for subsequent energy spectrum analysis.
[0090] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.
Claims
1. A method for extracting nuclear pulse amplitude based on parameter identification, characterized in that, Includes the following steps: Step 1. Acquire the electrical signal from the digital nuclear energy spectrum measurement system, and obtain a negative exponentially decaying pulse signal through a preamplifier circuit. ; Negative exponential decay pulse signal Specifically, it is expressed as follows: Where t represents the discrete-time variable, and i represents the sequence number of the nuclear pulse signal. This represents the negatively exponentially decaying pulse signal at time t. This represents the noise signal at time t. A represents a unit step signal. i T represents the amplitude coefficient of the i-th nuclear pulse signal. i The time of occurrence of the i-th nuclear pulse signal is represented by τ, the attenuation coefficient is represented by N, and the total number of nuclear pulse signals is represented by N. Step 2. Apply negative exponentially decaying pulse signals The baseline is estimated using a filtering method to obtain the baseline value. and based on baseline values After drift correction, a negative exponential decay signal is obtained. Baseline value Specifically, it is expressed as follows: in, This represents the i-th baseline sample value. and These represent the i-th and (i-1)-th baseline values after filtering, respectively. Indicates the weighting calculation factor; Drift correction is specifically expressed as: in, This represents a negative exponentially decaying pulse signal after drift correction; Step 3. Set the filtering time parameter t a With t b A joint filtering shaping method is used to transform the negative exponentially decaying signal. Converted into triangular pulse signal With trapezoidal pulse signal ; Step 4. Search for triangular pulse signals For any given triangular peak moment, ... The corresponding triangular pulse peak value is obtained. half-maximum amplitude of the falling edge of the triangular pulse Simultaneously, the trapezoidal pulse peak value was obtained through the search. Central amplitude of trapezoidal pulse ; Step 5. Establish the stacking discrimination condition, for any triangular peak time. If the accumulation criterion is met, then the signal is determined to be a negative exponential decay signal. The amplitude coefficient A of the accumulated pulse signal is obtained by the parameter identification model. i Otherwise, obtain the trapezoidal pulse peak value. As the amplitude of the trapezoidal pulse; The parameter identification model identifies the amplitude coefficient A of the stacked pulse signal. i The specific process is as follows: the accumulated pulse signal is fed into the parameter identification model to obtain the attenuation coefficient τ and amplitude coefficient A of the accumulated pulse signal. i With time T i And generate parameters (attenuation coefficient τ, amplitude coefficient A) i With time T i The trapezoidal pulse signal obtained Calculate the amplitude of the trapezoidal pulse. With trapezoidal pulse amplitude The difference E is calculated, and when the absolute value of the difference E is less than a preset threshold, the recognition ends and the corresponding amplitude coefficient A is output. i Otherwise, continue iterating; Step 6. Generate a nuclear pulse energy spectrum based on the amplitude coefficients of all extracted trapezoidal pulses and the stacked pulse signal, thus completing the nuclear pulse signal amplitude extraction.
2. The nuclear pulse amplitude extraction method based on parameter identification according to claim 1, characterized in that, In step 3, the triangular pulse signal Represented as: in, , , τ is the attenuation coefficient. Indicates the sampling period.
3. The nuclear pulse amplitude extraction method based on parameter identification according to claim 1, characterized in that, In step 3, the trapezoidal pulse signal Represented as: in, , , , τ is the attenuation coefficient. Indicates the sampling period.
4. The nuclear pulse amplitude extraction method based on parameter identification according to claim 1, characterized in that, In step 5, the stacking discrimination condition is that any of the following conditions are met: First criterion: , First criterion: .
5. A digital multichannel pulse analysis system, characterized in that, The digital multichannel pulse analysis system is used to execute the nuclear pulse amplitude extraction method based on parameter identification as described in claim 1, specifically including: The digital baseline estimation module is used to implement filtering and drift correction. It estimates the baseline using filtering and performs drift correction on the negative exponential decay signal based on the baseline value. The digital filtering shaping module is used to establish a dual-channel joint filtering shaping method, which converts the negative exponential decay signal after drift correction into a triangular pulse signal and a trapezoidal pulse signal. The pulse amplitude extraction module is used to search for the peak time of the triangular pulse signal and extract the corresponding amplitude parameters. The pulse accumulation judgment module is used to establish accumulation judgment conditions and judge the accumulated pulse signal based on the amplitude parameter; The pulse accumulation parameter identification module is used to establish a parameter identification model and identify the amplitude coefficient of the accumulated pulse signal through the parameter identification model. The digital energy spectrum generation module is used to generate nuclear pulse energy spectra based on the amplitude of the trapezoidal pulse and the amplitude coefficient of the stacked pulse signal.