CN-122017937-A - Signal pulse amplitude analysis method and system based on parallel double channels

CN122017937ACN 122017937 ACN122017937 ACN 122017937ACN-122017937-A

Abstract

The invention discloses a signal pulse amplitude analysis method and system based on parallel double channels, and relates to the technical field of energy spectrum measurement. The method comprises the steps of inputting pulse signals into a fast forming processing channel and a slow forming processing channel in parallel, carrying out bipolar peaked forming processing on the pulse signals in the fast forming processing channel, judging whether the pulses are piled up or not based on peak values and time intervals of the bipolar peaked pulse signals, generating pile mark signals or pile discarding mark signals, carrying out trapezoidal forming processing on the pulse signals in the slow forming processing channel, dynamically adjusting forming parameters of trapezoidal pulses according to the pile mark signals to separate the pile pulses, discarding amplitude extraction of corresponding pile pulses according to the pile discarding mark signals, extracting the amplitude of the separated or processed trapezoidal pulses, and carrying out energy spectrum analysis and statistics to form energy spectrums. The invention solves the problem that the energy resolution and the detection efficiency of the single-channel trapezoidal forming algorithm are difficult to be compatible.

Inventors

LIU BAOHUA
REN RONG
ZHOU WEI
CHEN WENTAO
XIA KEYING
HONG XU
CHENG XIAOBO
Sun Xunjie
CHEN WANLIANG
DAI JIACHENG

Assignees

广东省环境辐射监测与核应急响应技术支持中心

Dates

Publication Date: 20260512
Application Date: 20260326

Claims (10)

1. The signal pulse amplitude analysis method based on the parallel double channels is characterized by comprising the following steps of: collecting pulse signals and performing analog-to-digital conversion, and then inputting the pulse signals after analog-to-digital conversion into a fast forming processing channel and a slow forming processing channel in parallel; In the rapid forming processing channel, performing bipolar sharp peak forming processing on the pulse signal after analog-to-digital conversion through a bipolar sharp peak forming algorithm to generate a bipolar sharp peak pulse signal with a steep front edge and a steep rear edge; Judging whether the pulse is piled up or not based on the peak value and the time interval of the bipolar peak pulse signal, and generating a piled up mark signal or a piled up discarding mark signal; In the slow forming processing channel, carrying out trapezoidal forming processing on the pulse signal after analog-to-digital conversion by using a trapezoidal forming algorithm to generate trapezoidal pulses with flat tops; Dynamically adjusting the forming parameters of the trapezoidal pulse according to the stacking mark signal sent by the rapid forming processing channel to separate stacking pulses; and extracting the amplitude of the separated or processed trapezoidal pulse, and carrying out energy spectrum analysis and statistics to form an energy spectrum.
2. The method of claim 1, wherein determining whether a pulse is piled up based on a peak value and a time interval of the bipolar peaked pulse signal, and generating a pile-up flag signal or a pile-up rejection flag signal comprises: setting a pile-up pulse identification threshold and a pile-up pulse discarding threshold, wherein the pile-up pulse identification threshold is larger than the pile-up pulse discarding threshold; Generating the pile-up mark signal when the time interval of the peak values of two adjacent effective bipolar peak pulse signals is smaller than the pile-up pulse identification threshold value; and generating the accumulation judgment mark signal when the time interval of the peak values of the adjacent two effective bipolar peak pulse signals is smaller than the accumulation pulse judgment threshold value.
3. The method for analyzing signal pulse amplitude based on parallel dual channels according to claim 2, wherein the determination of the effective bipolar tip pulse signal is that the bipolar tip pulse signal is determined to be an effective bipolar tip pulse signal when the bipolar tip pulse signal amplitude is greater than or equal to an effective signal determination amplitude threshold.
4. The method for analyzing signal pulse amplitude based on parallel dual channels according to claim 1, wherein said trapezoidal shaping process has a transfer function Obtained by a Z-transform method, the expression is: ; where z represents a variable in the complex frequency domain; the attenuation factor is indicated as such, , In order to sample the period of time, A time constant that is a single-side negative exponent signal; 、、 The time when the trapezoid rises to reach the flat top, the end time of the trapezoid flat top and the sampling point number after the discretization of the total assembly time are respectively represented, namely the normalized integer representation of the corresponding time parameter under the sampling period.
5. The method of claim 4, wherein dynamically adjusting the forming parameters of the trapezoidal pulses based on the pile-up flag signal sent by the fast forming processing channel to separate the pile-up pulses comprises adjusting the forming parameters of the trapezoidal pulses, the rise time Peace time So that , Representing the minimum time interval of the peaks of two adjacent active bipolar pinnacle pulse signals.
6. The method of claim 1, wherein extracting the amplitude of the separated or processed trapezoidal pulse comprises: the method comprises the steps of carrying out arithmetic average on the amplitude values of a plurality of sampling points in a flat-top section of a trapezoidal pulse to obtain a flat-top amplitude value, obtaining a noise floor as a base line value, and subtracting the base line value from the flat-top amplitude value to obtain an effective amplitude value of a pulse signal.
7. A signal pulse amplitude analysis system based on parallel dual channels, which is used for realizing the signal pulse amplitude analysis method based on parallel dual channels according to any one of claims 1-6, wherein the system comprises: The signal acquisition module is used for acquiring pulse signals and performing analog-to-digital conversion, and then inputting the pulse signals after analog-to-digital conversion into the fast forming processing channel and the slow forming processing channel in parallel; The rapid forming processing channel is connected with the signal acquisition module and is used for carrying out bipolar peak forming processing on the pulse signal after analog-digital conversion through a bipolar peak forming algorithm to generate a bipolar peak pulse signal with a steep front edge and a steep rear edge; The slow forming processing channel is connected with the signal acquisition module and the fast forming processing channel and is used for carrying out trapezoidal forming processing on the pulse signals subjected to analog-to-digital conversion through a trapezoidal forming algorithm to generate trapezoidal pulses with flat tops; the amplitude extraction module is connected with the slow forming processing channel and is used for extracting the amplitude of the trapezoid pulse after separation or processing; And the energy spectrum statistics module is connected with the amplitude extraction module and is used for carrying out energy spectrum analysis and statistics based on the extracted amplitude so as to form an energy spectrum.
8. The parallel dual channel based signal pulse amplitude analysis system of claim 7, wherein the fast shaping processing channel comprises: A bipolar tip forming unit configured to generate a bipolar tip pulse signal based on performing delay difference, integration, and convolution operations on an input negative exponent signal; and a pile-up identification unit configured to identify peaks of the effective bipolar-peak pulse signal and compare time intervals of adjacent peaks with a preset threshold value to generate a pile-up flag signal and a pile-up rejection flag signal.
9. The parallel dual channel based signal pulse amplitude analysis system of claim 8, wherein the slow shaping processing channel comprises: The trapezoidal shaping unit with adjustable parameters is configured to perform trapezoidal shaping treatment on the pulse signal after analog-digital conversion through a trapezoidal shaping algorithm to generate trapezoidal pulses with flat tops; And a forming parameter control unit configured to dynamically control a trapezoidal pulse forming parameter in the trapezoidal forming unit in response to the pile-up flag signal transmitted by the rapid-forming processing channel.
10. The system of claim 9, wherein the system is implemented based on an FPGA, the signal acquisition module includes an ADC converter, and the fast-forming processing channel, the slow-forming processing channel, the amplitude extraction module, and the energy spectrum statistics module are all implemented in hardware logic in the FPGA.

Description

Signal pulse amplitude analysis method and system based on parallel double channels Technical Field The invention relates to the technical field of energy spectrum measurement, in particular to a signal pulse amplitude analysis method and system based on parallel double channels. Background Nuclear radiation energy spectrum measurement technology is the basis of the fields of nuclear technology application, radioactivity monitoring, resource exploration, nuclear medicine and the like. The core principle is that a sensor such as a scintillator detector converts the energy of incident particles into a weak current pulse signal, and the amplitude of the pulse signal is proportional to the energy of the particles. Therefore, the amplitude of the pulse signal is precisely measured and the distribution (namely, multi-channel pulse amplitude analysis, MCA) is counted, so that the energy spectrum reflecting the nuclide characteristics can be obtained. In a digital multichannel pulse amplitude analysis system, after a signal output by a detector passes through a preamplifier, the signal is usually a single-side negative index signal with longer decay time. The signal is directly sampled and the peak value is searched to obtain the amplitude value, the signal is easy to be interfered by noise, the requirement on sampling timing is extremely high, and the error is large. Therefore, digital pulse shaping filtering techniques are central, the purpose of which is to shape the signal into a shape that facilitates accurate extraction of amplitude, such as bell-shaped (gaussian shaping) or trapezoidal (trapezoidal shaping), while suppressing noise. Among them, the trapezoidal shaping algorithm is widely used because of its good balance between signal-to-noise ratio, count rate performance and implementation complexity. However, in a high count rate measurement scenario, the radioactive events occur frequently, and the fore-and-aft pulse signals may overlap in time, i.e., pulse pile-up occurs. For the traditional filtering algorithm (such as trapezoidal shaping with fixed shaping parameters) adopting fixed shaping parameters, pulse accumulation can bring about two serious problems, namely 1) amplitude extraction distortion, namely distortion of the waveform of accumulated pulses, peak value or flat top height, which cannot truly reflect the energy of original particles, so that energy spectrum peak position deviation and resolution deterioration are caused, and 2) pseudo-counting and leakage counting, namely serious accumulation, which can cause that a plurality of particle events are identified by single trigger or can not be effectively triggered, so that counting statistics of energy spectrum are distorted. Therefore, developing a pulse amplitude analysis method that can adaptively process pulse pile-up while maintaining high measurement efficiency and high energy resolution at high count rates is an urgent issue. Disclosure of Invention In order to solve or alleviate one or more of the above-mentioned technical problems, the present invention provides a signal pulse amplitude analysis method and system based on parallel dual channels. According to an aspect of the present invention, a signal pulse amplitude analysis method based on parallel dual channels is provided, the method comprising the following steps: collecting pulse signals and performing analog-to-digital conversion, and then inputting the pulse signals after analog-to-digital conversion into a fast forming processing channel and a slow forming processing channel in parallel; In the rapid forming processing channel, performing bipolar sharp peak forming processing on the pulse signal after analog-to-digital conversion through a bipolar sharp peak forming algorithm to generate a bipolar sharp peak pulse signal with a steep front edge and a steep rear edge; Judging whether the pulse is piled up or not based on the peak value and the time interval of the bipolar peak pulse signal, and generating a piled up mark signal or a piled up discarding mark signal; In the slow forming processing channel, carrying out trapezoidal forming processing on the pulse signal after analog-to-digital conversion by using a trapezoidal forming algorithm to generate trapezoidal pulses with flat tops; Dynamically adjusting the forming parameters of the trapezoidal pulse according to the stacking mark signal sent by the rapid forming processing channel to separate stacking pulses; and extracting the amplitude of the separated or processed trapezoidal pulse, and carrying out energy spectrum analysis and statistics to form an energy spectrum. Further, the step of judging whether the pulse is piled up based on the peak value and the time interval of the bipolar peak pulse signal, and generating a pile-up flag signal or a pile-up judging flag signal comprises: setting a pile-up pulse identification threshold and a pile-up pulse discarding threshold, wherein the pile-up pulse identification t