Digital pulse reconstruction method, system and device and storage medium

Abstract

The invention relates to a digital pulse reconstruction method, system and device and a storage medium, and the method comprises the steps: carrying out the measurement of gamma rays based on a radiation detector, and obtaining an initial impulse response with a certain amplitude; converting the initial impulse response into a double-exponential decay pulse with a time constant; acquiring a single exponential pulse related to the time constant; the single-exponential pulse and the double-exponential decay pulse are subjected to convolution, a reconstruction impulse response with a certain amplitude is obtained, convolution is used for removing the influence of the time constant on the double-exponential decay pulse, and the amplitude of the reconstruction impulse response is the same as the amplitude of the initial impulse response. According to the invention, the method achieves the purpose of removing the influence of the time constant on the double-exponential decay pulse through the convolution of the single-exponential pulse and the double-exponential decay pulse, thereby achieving the technical effects of considering the influence caused by the change of the time constant and enabling the final measurement result to be more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of gamma pulse signal processing, and in particular to a digital pulse reconstruction method, system, device and storage medium. Background Art

[0002] Gamma spectrum measurement is a key method for radionuclide identification. At present, the spectrum measurement of radionuclides is mainly achieved through analog multi-channel analyzers and digital multi-channel analyzers. In the analog multi-channel analyzer, the decaying exponential pulse output by the preamplifier realizes real-time statistics of pulse amplitude through peak hold, amplitude extraction and baseline recovery to form spectrum data. With the rapid development of high-speed analog-to-digital converters and programmable logic devices, digital multi-channel analyzers have become the main solution for spectrum measurement. The digital multi-channel analyzer converts the decaying exponential pulse signal into a discrete digital signal through a high-speed analog-to-digital converter, and then uses a digital pulse shaping algorithm to count the number of pulse amplitudes in real time to form spectrum data. The digital pulse shaping algorithm is a key technology for spectrum measurement, which directly affects the resolution and other parameters of the spectrum.

[0003] In the related art, the discrete signal sampled by the high-speed analog-to-digital converter is directly input into the digital pulse shaping algorithm for processing. However, when the detector is replaced or the circuit is changed, the pulse time constant may change, which will cause the energy resolution of the energy spectrum data or the pulse pass rate to deteriorate, affecting the measurement results.

[0004] The related technology fails to consider the impact of changes in the pulse time constant, resulting in inaccurate final measurement results.

[0005] The above problems need to be solved urgently. Summary of the invention

[0006] The invention discloses a digital pulse reconstruction method, system, device and storage medium, aiming to solve the technical problems existing in the prior art.

[0007] The present invention adopts the following technical solutions:

[0008] On the one hand, the present invention provides a digital pulse reconstruction method, which includes: measuring gamma rays based on a radiation detector to obtain an initial impulse response with a certain amplitude; converting the initial impulse response into a double exponential decay pulse with a time constant; obtaining a single exponential pulse related to the time constant; convolving the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0009] Optionally, the converting of the initial impulse response into a double exponential decay pulse with a time constant comprises: based on a first circuit connected to the radiation detector, converting the initial impulse response into a decaying exponential pulse with a time constant, wherein the first circuit comprises at least a resistor and a capacitor; based on a second circuit connected to the first circuit, converting the decaying exponential pulse into a double exponential decay pulse, wherein the double exponential decay pulse comprises a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b .

[0010] Optionally, when the decaying exponential pulse is converted into a time-continuous double exponential decay pulse through the second circuit, the method further includes: based on a high-speed analog-to-digital converter, quantizing and encoding the time-continuous double exponential decay pulse to obtain a discrete double exponential decay pulse.

[0011] Optionally, the acquiring of a single exponential pulse associated with the time constant comprises: wherein the double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b In the case of A (n) and the second index pulse h B (n); the first index pulse h A (n) are as follows:

[0012]

[0013] Where ΔT is the signal sampling frequency; τ a is the signal rising edge decay time constant;

[0014] The second index pulse h B (n) are as follows:

[0015]

[0016] Where ΔT is the signal sampling frequency; τ b is the signal falling edge decay time constant.

[0017] Optionally, the convolution of the single exponential pulse and the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude includes: based on the double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The influence of the double exponential decay pulse on the convolution pulse is obtained; based on the convolution pulse and the second exponential pulse h B(n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The effect of a double exponential decay pulse is used to obtain the reconstructed impulse response.

[0018] Optionally, the double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The influence of the double exponential decay pulse on the convolution pulse is obtained, including: the double exponential decay pulse includes a signal rising edge decay time constant τ a The first decay pulse and the decay time constant τ of the falling edge of the signal b The second decay pulse;

[0019] The convolution pulse is as follows:

[0020] y A (n) = [x A (n)-x B (n)]*h A (n)

[0021] Among them, y A (n) is the convolution pulse, x A (n) is the first decay pulse, x B (n) is the second decay pulse, h A (n) is the first index pulse.

[0022] Optionally, the convolution pulse and the second exponential pulse h B (n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The influence of the double exponential decay pulse is obtained to obtain a reconstructed impulse response, including: the reconstructed impulse response is as follows:

[0023] y(n)={[x A (n)-x B (n)]*h A (n)}*h B (n)

[0024] Where y(n) is the reconstructed impulse response, x A (n) is the first decay pulse, x B (n) is the second decay pulse, h B (n) is the second index pulse.

[0025] Optionally, the method further includes: taking the reconstructed impulse response as input to a digital pulse shaping algorithm, counting the amplitude of the reconstructed impulse response to obtain the number of pulse amplitudes; forming energy spectrum data based on the number of pulse amplitudes; and displaying the energy spectrum data on a terminal.

[0026] According to another aspect of an embodiment of the present invention, a digital pulse reconstruction system is also provided, including: a radiation detector for measuring gamma rays to obtain an initial impulse response with a certain amplitude; a signal conditioning circuit connected to the radiation detector, for converting the initial impulse response into a time-continuous double exponential decay pulse; a high-speed analog-to-digital converter connected to the signal conditioning circuit, for converting the time-continuous double exponential decay pulse into a discrete double exponential decay pulse; an FPGA digital signal processing module connected to the high-speed analog-to-digital converter, for performing convolution processing on the discrete double exponential decay pulse and inputting it into a digital pulse shaping algorithm to obtain energy spectrum data; and a terminal connected to the FPGA digital signal processing module, for displaying the energy spectrum data.

[0027] Optionally, the signal conditioning circuit includes: a first circuit, connected to the radiation detector, for converting the initial impulse response into a decaying exponential pulse with a time constant, wherein the first circuit includes at least a resistor and a capacitor; a second circuit, connected to the first circuit, for converting the decaying exponential pulse into a double exponential decay pulse, wherein the double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b .

[0028] According to another aspect of an embodiment of the present invention, a digital pulse reconstruction device is also provided, characterized in that it includes: a measurement module, used to measure gamma rays based on a radiation detector to obtain an initial impulse response with a certain amplitude; a conversion module, used to convert the initial impulse response into a double exponential decay pulse with a time constant; a determination module, used to obtain a single exponential pulse related to the time constant; a convolution module, used to convolve the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0029] According to another aspect of an embodiment of the present invention, a non-volatile storage medium is provided, wherein the non-volatile storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded by a processor and executing any one of the digital pulse reconstruction methods.

[0030] According to another aspect of an embodiment of the present invention, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps of any one of the digital pulse reconstruction methods are implemented.

[0031] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0032] In an embodiment of the present invention, gamma rays are measured based on a radiation detector to obtain an initial impulse response with a certain amplitude; the initial impulse response is converted into a double exponential decay pulse with a time constant; a single exponential pulse related to the time constant is obtained; the single exponential pulse is convolved with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response, thereby achieving the purpose of removing the influence of the time constant on the double exponential decay pulse by convolving the single exponential pulse with the double exponential decay pulse, thereby achieving the technical effect of taking into account the influence of the change of the time constant to make the final measurement result more accurate, and further solving the technical problem of inaccurate final measurement results due to failure to consider the influence of the change of the pulse time constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0034] Figure 1 is a flow chart of a digital pulse reconstruction method in embodiment 1 of the present invention;

[0035] Figure 2 is a circuit diagram of a radiation detector signal processing circuit according to Embodiment 1 of the present invention;

[0036] Figure 3 is a flow chart of an optional digital pulse reconstruction method in embodiment 2 of the present invention;

[0037] Figure 4 is a gamma spectrum measurement system architecture diagram of embodiment 2 of the present invention;

[0038] Figure 5 is a signal waveform diagram after quantization and encoding by the high-speed analog-to-digital converter of embodiment 2 of the present invention;

[0039] Figure 6 is a result diagram after the pulse reconstruction algorithm of Example 2 of the present invention;

[0040] Figure 7 is a process diagram of a pulse reconstruction algorithm according to Embodiment 2 of the present invention;

[0041] Figure 8is a connection diagram of electrical components of a digital pulse reconstruction system in embodiment 3 of the present invention;

[0042] Fig. 9 It is a structural schematic diagram of a digital pulse reconstruction device in Example 4 of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically limited.

[0045] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] First, to facilitate understanding of the embodiments of the present invention, some terms or nouns involved in the present invention are explained below:

[0047] Pulse refers to a pulse-like short-term electric shock (voltage or current) signal that is often used in electronic technology. This signal has no signal in most of the signal cycle and only occurs in a short period of time, just like a human pulse. The main characteristic parameters of the pulse signal include waveform, amplitude, width and repetition frequency.

[0048] Gamma rays, also known as gamma rays or gamma particle streams, are a type of high-energy electromagnetic radiation released by atomic nuclei during radioactive decay or nuclear reactions.

[0049] Convolution is a mathematical operation that generates a third function from two functions f and g. Its essence is a special integral transformation, which represents the integral of the product of the overlapping function values ​​of the functions f and g after flipping and translating over the overlapping length.

[0050] To solve the problems existing in the prior art, the embodiments of the present application provide a digital pulse reconstruction method, system, device and storage medium.

[0051] Example 1

[0052] This embodiment provides a digital pulse reconstruction method, such as Figure 1 As shown, Figure 1 is a flow chart of a digital pulse reconstruction method in embodiment 1 of the present invention, the method comprising:

[0053] Step S102, measuring the gamma rays based on the radiation detector to obtain an initial impulse response with a certain amplitude;

[0054] Optionally, when a radiation detector measures gamma rays, an initial impulse response (also called pulse response or transient response) with a certain amplitude is obtained, which is the immediate response of the radiation detector to the gamma ray radiation. This response contains important information about the energy and intensity of the gamma rays and the performance of the radiation detector. Among them, gamma rays are high-energy electromagnetic waves. When they interact with matter (such as sensitive materials in radiation detectors), various physical processes occur, such as the photoelectric effect, Compton scattering, and the process of electron pair generation. These processes cause atoms or molecules in the radiation detector to be excited or ionized, thereby generating signals that can be detected by the radiation detector. In addition, when gamma rays interact with the radiation detector, an electrical signal (or pulse, initial impulse response) is immediately generated. The amplitude of the initial impulse response is related to the energy of the gamma ray and the energy conversion efficiency of the radiation detector. Generally, the higher the energy of the gamma ray, the larger the signal amplitude. In addition, the design of the radiation detector (such as sensitivity, response time, etc.) will also affect the shape and amplitude of the initial impulse response.

[0055] Step S104, converting the initial impulse response into a double exponential decay pulse with a time constant;

[0056] Optionally, the initial impulse response is converted into a double exponential decay pulse with a time constant, and a signal conditioning circuit can be used for direct conversion, or analog conversion can be performed using simulation software based on mathematical modeling of the initial impulse response output by the radiation detector.

[0057] Optionally, in radiation measurement, especially when using scintillator-type radiation detectors, the double exponential decay model is a commonly used method to describe the response of the radiation detector. The specific double exponential decay pulse is as follows:

[0058]

[0059] Among them, V M is the amplitude of the double exponential decay pulse; τ a is the signal rising edge decay time constant, τ b is the decay time constant of the falling edge of the signal, ΔT is the signal sampling frequency; specifically, τ a <<τ b , τ a Related to capacitor C1, resistor R2 and junction capacitance, τ b Related to feedback capacitor C4 and feedback resistor R3.

[0060] Optionally, based on mathematical modeling of the initial impulse response output by the radiation detector, when using simulation software for analog conversion, the specific working steps of the double exponential decay model are as follows:

[0061] Step S1041, obtaining the initial impulse response output by the radiation detector, which is usually accomplished through a data acquisition system (such as an oscilloscope or a data acquisition card).

[0062] Step S1042, preprocessing the acquired initial impulse response, such as denoising, baseline correction, etc., to ensure the accuracy of the data.

[0063] Step S1043: Use a double exponential decay model to fit the preprocessed initial impulse response.

[0064] Step S1044, extract V from the fitting results M , τ a , τ b These parameters describe the characteristics of the double exponential decay pulse.

[0065] Step S1045 , verifying the accuracy of the model by comparing the fitted curve with the initial impulse response.

[0066] In some preferred embodiments, the initial impulse response is converted into a double exponential decay pulse with a time constant, including: based on a first circuit connected to the radiation detector, the initial impulse response is converted into a decaying exponential pulse with a time constant, wherein the first circuit at least includes a resistor and a capacitor; based on a second circuit connected to the first circuit, the decaying exponential pulse is converted into a double exponential decay pulse, wherein the double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τb .

[0067] Optionally, in addition to the above analog software for conversion, a signal conditioning circuit can also be used for direct conversion, such as Figure 2 As shown, Figure 2 is a circuit diagram of the detector signal processing circuit of Example 1 of the present invention, which converts the output initial impulse response function with amplitude into a constant with amplitude time τ a The initial impulse response function is converted into a decaying exponential pulse with a time amplitude due to the effect of the capacitor C1, the resistor R2 and the junction capacitance between the radiation detector and the bias high voltage.

[0068] Optionally, under the action of the feedback capacitor C4 and the feedback resistor R3 of the charge sensitive preamplifier, the above-mentioned decaying exponential pulse is transformed into a double exponential decaying pulse with time amplitude, wherein the amplitude of the double exponential decaying pulse is the same as the amplitude of the decaying exponential pulse.

[0069] In some preferred embodiments, when the decaying exponential pulse is converted into a time-continuous double exponential decay pulse through a second circuit, the method further includes: quantizing and encoding the time-continuous double exponential decay pulse based on a high-speed analog-to-digital converter to obtain a discrete double exponential decay pulse.

[0070] Optionally, a high-speed analog-to-digital converter is an electronic device used to convert a continuous analog signal (a time-continuous double exponential decay pulse) into a discrete digital signal (a discrete double exponential decay pulse). The high-speed analog-to-digital converter mainly includes three steps: sampling, quantization, and encoding.

[0071] Specifically, during the sampling process of the high-speed analog-to-digital converter, the time-continuous double exponential decay pulse changes continuously, while the discrete double exponential decay pulse is time-discrete. Therefore, the time-continuous double exponential decay pulse needs to be sampled, that is, the time-continuous double exponential decay pulse is measured within a specific time interval. During the sampling process, the amplitude of the time-continuous double exponential decay pulse is recorded as the sampling value. The sampling frequency refers to the number of samples per second, usually in Hertz (Hz). According to the Nyquist theorem, the sampling frequency must be at least twice the highest frequency of the signal to accurately reconstruct the analog signal.

[0072] The quantization process of the high-speed analog-to-digital converter is to convert the sampled values ​​into discrete double exponential decay pulses, that is, to map the continuous double exponential decay pulses to a series of discrete values. The sampled values ​​are mapped to a fixed number of discrete levels, and the number of quantization levels determines the accuracy and resolution of the discrete double exponential decay pulses.

[0073] Finally, the high-speed analog-to-digital converter encodes the quantized discrete double exponential decay pulses. The encoding process represents the discrete double exponential decay pulses as binary codes to facilitate subsequent digital signal processing and analysis.

[0074] Step S106, obtaining a single exponential pulse associated with a time constant;

[0075] In some preferred embodiments, obtaining a single exponential pulse associated with a time constant includes: a double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b In the case of single exponential pulses, the first exponential pulse h A (n) and the second index pulse h B (n); first index pulse h A (n) are as follows:

[0076]

[0077] Where ΔT is the signal sampling frequency; τ a is the signal rising edge decay time constant;

[0078] The second index pulse h B (n) are as follows:

[0079]

[0080] Where ΔT is the signal sampling frequency; τ b is the signal falling edge decay time constant.

[0081] Optionally, a single exponential pulse associated with a time constant is obtained, wherein the obtained single exponential pulse is prepared for the subsequent removal of the influence of the time constant on the double exponential decay pulse, so the time constant in the single exponential pulse must be the same as the time constant in the double exponential decay pulse. Since there are two time constants (τ a , τ b ), so two different single exponential pulses are needed, and the time constants of the two single exponential pulses are τ a , τ b .

[0082] Optionally, based on the time amplitude in the double exponential decay pulse, the time series in the single exponential pulse is determined, that is, the time range of the analog signal, for example, from t = 0 to t = T, and a sequence of equally spaced time points is generated within this time range. Based on the above time range, the time constant is τ a or τ b , a pulse with an amplitude of unit exponent, which is the single exponential pulse required subsequently.

[0083] Step S108, convolving the single exponential pulse and the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0084] In some preferred embodiments, a single exponential pulse is convolved with a double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, including: based on the double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The influence of the double exponential decay pulse on the convolution pulse is obtained; based on the convolution pulse and the second exponential pulse h B (n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The effect of a double exponential decay pulse is used to obtain the reconstructed impulse response.

[0085] In some preferred embodiments, based on the double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The influence of the double exponential decay pulse on the convolution pulse is obtained, including: the double exponential decay pulse includes a signal rising edge decay time constant τ a The first decay pulse and the decay time constant τ of the falling edge of the signal b The second decay pulse of; the convolution pulse is as follows:

[0086] y A (n) = [x A (n)-x B (n)]*h A (n)

[0087] Among them, y A (n) is the convolution pulse, x A (n) is the first decay pulse, x B (n) is the second decay pulse, h A (n) is the first index pulse.

[0088] Optional, to eliminate the time constant τ a and τ b The influence of the discrete double exponential decay pulse and the signal rising edge decay time constant τ a The single exponential pulse (the first exponential pulse h A (n)) to perform convolution operation to eliminate the signal rising edge decay time constant τ a Impact on the signal, obtain function y A (n).

[0089] Optionally, a double exponential decay pulse is a τ a and τ b The combined pulse function effectively eliminates τ a , we need to replace the τ in the double exponential decay pulse a and τ b Splitting, that is, splitting into addition or subtraction forms, is as follows:

[0090]

[0091] Among them, x A (n) is the time constant τ a Decaying pulse, x B (n) is the time constant τ b decay pulse.

[0092] Based on the above obtained h N (n) = x A (n)-x B (n), for x A The time constant of the rising edge attenuation of the elimination signal in (n) is τ a The impact on the signal is as follows:

[0093] y A (n) = [x A (n)-x B (n)]*h A (n) = δ(n) - x B (n)*h A (n)

[0094] Among them, δ(n) is the discrete time unit pulse function, h A (n) is the first exponential pulse (the decay time constant of the rising edge of the signal is τ a single exponential pulse),

[0095] In some preferred embodiments, based on the convolution pulse and the second index pulse h B (n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The influence of the double exponential decay pulse is obtained to reconstruct the impulse response, including: The reconstructed impulse response is as follows:

[0096] y(n)={[x A (n)-x B (n)]*h A (n)}*h B (n)

[0097] Where y(n) is the reconstructed impulse response, x A(n) is the first decay pulse, x B (n) is the second decay pulse, h B (n) is the second index pulse.

[0098] Optionally, the decay time constant of the rising edge of the elimination signal is τ a Based on the impact on the signal, y A (n) and the decay time constant of the falling edge of the signal is τ b The single exponential pulse is convolved to eliminate the signal falling edge decay time constant τ b The influence on the signal is obtained, and the corresponding reconstructed impulse response y(n) with amplitude is obtained, as follows:

[0099] y(n)=[δ(n)-x B (n)*h A (n)]*h B (n) = h B (n)-h A (n)

[0100]

[0101] Among them, h B (n) is the second exponential pulse (the decay time constant of the falling edge of the signal is τ b single exponential pulse),

[0102] In some preferred embodiments, the method further includes: taking the reconstructed impulse response as input to a digital pulse shaping algorithm, counting the amplitude of the reconstructed impulse response to obtain the number of pulse amplitudes; forming energy spectrum data based on the number of pulse amplitudes; and displaying the energy spectrum data on a terminal.

[0103] Through the above steps S102 to S108, the purpose of removing the influence of the time constant on the double exponential decay pulse by convolving the single exponential pulse with the double exponential decay pulse is achieved, thereby achieving the technical effect of taking into account the influence of the change in the time constant and making the final measurement result more accurate, thereby solving the technical problem of inaccurate final measurement results due to failure to consider the influence of the change in the pulse time constant.

[0104] Example 2

[0105] Based on the above embodiments and optional embodiments, the present invention also proposes an optional implementation mode: Figure 3 is a flow chart of an optional digital pulse reconstruction method in embodiment 2 of the present invention, such as Figure 3 As shown, the method includes:

[0106] Step S1, gamma rays interact with the radiation detector to generate a weak current signal, forming an initial impulse response (δ(t) function) of a certain amplitude.

[0107] The gamma spectrum measurement system consists of a radiation detector, a signal conditioning circuit (preamplifier and signal processor), a high-speed analog-to-digital converter (high-speed analog-to-digital converter (ADC) circuit), a FPGA-based digital signal processing module (FPGA (Field-Programmable Gate Array, Field Programmable Gate Array)) and a terminal. Figure 4 As shown, Figure 4 This is a diagram of the gamma spectrum measurement system architecture of Example 2 of the present invention.

[0108] Step S2, converting the outputted initial impulse response function with amplitude into a decaying exponential pulse with an amplitude-time constant of τa (less than 2μs). Figure 2 As shown, the above initial impulse response function is transformed into a decaying exponential pulse due to the influence of the capacitor C1, the resistor R2 and the junction capacitance between the radiation detector and the bias high voltage.

[0109] Step S3, transforming the decaying exponential pulse into a double exponential decaying pulse with time amplitude, wherein the transformation is produced by the feedback capacitor C4 and the feedback resistor R3 of the charge sensitive preamplifier.

[0110] Step S4, a high-speed analog-to-digital converter is used to quantize and encode the discrete double exponential decay pulse. That is, a faster rising edge and a slower falling edge. The time constant of the entire double exponential decay pulse function is about 200 μs (semiconductor) or 10 μs (scintillator). Figure 5 As shown, Figure 5 : is a signal waveform diagram of the high-speed analog-to-digital converter after quantization and encoding according to Embodiment 2 of the present invention, and the expression of its double exponential decay pulse function is as follows:

[0111]

[0112] Among them, V M is the amplitude of the double exponential decay pulse; τ a is the signal rising edge decay time constant, τ b is the decay time constant of the falling edge of the signal, ΔT is the signal sampling frequency; specifically, τ a <<τ b , τ a Related to capacitor C1, resistor R2 and junction capacitance, τ b Related to feedback capacitor C4 and feedback resistor R3.

[0113] Step S5, through the pulse reconstruction algorithm, the discrete double exponential decay pulse (original signal) is restored into an impulse function signal with amplitude, wherein the amplitude of the impulse function signal is V M , the time constant of the pulse is about 300ns. Figure 6 As shown, Figure 6 This is a diagram showing the result of the pulse reconstruction algorithm of Example 2 of the present invention.

[0114] Specifically, the discrete double exponential decay pulse and the signal rising edge decay time constant τ are firstly connected. a The single exponential pulse is convolved to eliminate the signal rising edge decay time constant τ a Impact on the signal, obtain function y A (n). Then y A (n) and the decay time constant of the falling edge of the signal is τ b The single exponential pulse is convolved to eliminate the signal falling edge decay time constant τ b The influence on the signal is obtained, and the corresponding reconstructed impulse response y(n) with amplitude is obtained. Figure 7 As shown, Figure 7 : is a process diagram of the pulse reconstruction algorithm of embodiment 2 of the present invention, and the specific derivation formula is as follows:

[0115]

[0116] y A (n) = [x A (n)-x B (n)]*h A (n) = δ(n) - x B (n)*h A (n)

[0117] y(n)=[δ(n)-x B (n)*h A (n)]*h B (n) = h B (n)-h A (n)

[0118]

[0119] Among them, h A (n) is the first exponential pulse (the decay time constant of the rising edge of the signal is τ a single exponential pulse), h B (n) is the second exponential pulse (the decay time constant of the falling edge of the signal is τ b single exponential pulse),

[0120] Step S6, performing trapezoidal, triangular or other shaping algorithms to form energy spectrum data.

[0121] Through the above steps S1 to S6, the processing can be performed according to the optimal shaping algorithm to improve the energy resolution of the digital pulse energy spectrum analyzer. At the same time, in the case of high counting rate, the pulse accumulation probability is reduced and the pulse passing rate is improved.

[0122] Example 3

[0123] According to an embodiment of the present invention, a digital pulse reconstruction system embodiment is also provided. Figure 8 As shown, Figure 8 This is a connection diagram of electrical components of a digital pulse reconstruction system in Example 3 of the present invention.

[0124] A digital pulse reconstruction system includes: a radiation detector for measuring gamma rays to obtain an initial impulse response with a certain amplitude; a signal conditioning circuit connected to the radiation detector and used to convert the initial impulse response into a time-continuous double exponential decay pulse; a high-speed analog-to-digital converter connected to the signal conditioning circuit and used to convert the time-continuous double exponential decay pulse into a discrete double exponential decay pulse; an FPGA digital signal processing module connected to the high-speed analog-to-digital converter and used to perform convolution processing on the discrete double exponential decay pulse and input it into a digital pulse shaping algorithm to obtain energy spectrum data; and a terminal connected to the FPGA digital signal processing module and used to display the energy spectrum data.

[0125] Based on the above structure, when the gamma ray is measured based on the radiation detector, the gamma ray interacts with the sensitive material in the radiation detector, and various physical processes occur, so that the atoms or molecules in the radiation detector are excited or ionized, thereby generating a signal that can be detected by the radiation detector, that is, the initial impulse response. After a series of transformations in the signal conditioning circuit, the initial impulse response is converted into a double exponential decay pulse. Under the action of the high-speed analog-to-digital converter, the double exponential decay pulse in the form of an analog signal is converted into a double exponential decay pulse in the form of a digital signal, that is, a discrete double exponential decay pulse is formed. After being processed by the FPGA digital signal processing module, the time constant in the discrete double exponential pulse is eliminated, leaving only the reconstructed impulse response with amplitude, and the digital pulse shaping algorithm is used based on the reconstructed impulse response with amplitude to obtain the energy spectrum data, which effectively removes the influence of the change in the time constant, thereby effectively achieving the accuracy of detection.

[0126] In some preferred embodiments, the signal conditioning circuit includes: a first circuit connected to the radiation detector, used to convert the initial impulse response into a decaying exponential pulse with a time constant, wherein the first circuit includes at least a resistor and a capacitor; a second circuit connected to the first circuit, used to convert the decaying exponential pulse into a double exponential decay pulse, wherein the double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b .

[0127] Based on the above structure, the output initial impulse response function with amplitude is converted into a decaying exponential pulse with an amplitude time constant of τa (less than 2μs). Figure 2 As shown, the above initial impulse response function is transformed into a decaying exponential pulse due to the influence of the capacitor C1, the resistor R2 and the junction capacitance between the radiation detector and the bias high voltage. The above decaying exponential pulse is transformed into a double exponential decay pulse with time amplitude. The above transformation is generated under the action of the feedback capacitor C4 and the feedback resistor R3 of the charge sensitive preamplifier.

[0128] Through the above-mentioned digital pulse reconstruction system, the purpose of removing the influence of the time constant on the double exponential decay pulse is achieved by convolving the single exponential pulse with the double exponential decay pulse, thereby achieving the technical effect of taking into account the influence of the change of the time constant and making the final measurement result more accurate, thereby solving the technical problem of inaccurate final measurement results due to failure to consider the influence of the change of the pulse time constant.

[0129] Example 4

[0130] In this embodiment, a digital pulse reconstruction device is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the terms "module" and "device" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0131] According to an embodiment of the present invention, a device embodiment for implementing the above-mentioned digital pulse reconstruction method is also provided. Fig. 9 is a schematic structural diagram of a digital pulse reconstruction device in Embodiment 4 of the present invention, such as Fig. 9 As shown, the digital pulse reconstruction device includes: a measurement module 401, a conversion module 402, a determination module 403 and a convolution module 404, wherein:

[0132] The measurement module 401 is used to measure the gamma rays based on the radiation detector to obtain an initial impulse response with a certain amplitude;

[0133] The conversion module 402 is connected to the measurement module 401 and is used to convert the initial impulse response into a double exponential decay pulse with a time constant;

[0134] A determination module 403, connected to the conversion module 402, for obtaining a single exponential pulse associated with a time constant;

[0135] The convolution module 404 is connected to the determination module 403 and is used to convolve the single exponential pulse and the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0136] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0137] It should be noted that the measurement module 401, the conversion module 402, the determination module 403 and the convolution module 404 correspond to steps S102 to S108 in the embodiment, and the examples and application scenarios implemented by the modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above embodiment. It should be noted that the modules as part of the device can be run in a computer terminal.

[0138] It should be noted that the optional or preferred implementation of this embodiment can refer to the relevant description in the embodiment, which will not be repeated here.

[0139] The above-mentioned digital pulse reconstruction device may also include a processor and a memory. The above-mentioned measurement module 401, conversion module 402, determination module 403 and convolution module 404 are all stored in the memory as program modules, and the processor executes the above-mentioned program modules stored in the memory to realize corresponding functions.

[0140] The processor includes a kernel, which retrieves the corresponding program module from the memory. The kernel may be one or more. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. The memory includes at least one memory chip.

[0141] According to an embodiment of the present application, an embodiment of a non-volatile storage medium is also provided. Optionally, in this embodiment, the non-volatile storage medium includes a stored program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute any one of the digital pulse reconstruction methods.

[0142] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a computer terminal group in a computer network, or in any mobile terminal in a mobile terminal group, and the non-volatile storage medium includes a stored program.

[0143] Optionally, when the program is running, the device where the non-volatile storage medium is located is controlled to perform the following functions: measure gamma rays based on the radiation detector to obtain an initial impulse response with a certain amplitude; convert the initial impulse response into a double exponential decay pulse with a time constant; obtain a single exponential pulse related to the time constant; convolve the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0144] According to an embodiment of the present application, an embodiment of a processor is also provided. Optionally, in this embodiment, the processor is used to run a program, wherein the program executes any one of the digital pulse reconstruction methods when running.

[0145] According to an embodiment of the present application, an embodiment of a computer program product is also provided. Optionally, in this embodiment, the computer program product includes a computer program, and when the computer program is executed by a processor, the computer program implements any one of the steps of the digital pulse reconstruction method.

[0146] Optionally, the above-mentioned computer program product, when executed on a data processing device, is suitable for executing a program initialized with the following method steps: measuring gamma rays based on a radiation detector to obtain an initial impulse response with a certain amplitude; converting the initial impulse response into a double exponential decay pulse with a time constant; obtaining a single exponential pulse related to the time constant; convolving the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0147] An embodiment of the present invention provides an electronic device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: measuring gamma rays based on a radiation detector to obtain an initial impulse response with a certain amplitude; converting the initial impulse response into a double exponential decay pulse with a time constant; acquiring a single exponential pulse related to the time constant; and convolving the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

[0148] The above sequence of the embodiments of the present invention is for description only and does not represent the superiority or inferiority of the embodiments.

[0149] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the above modules can be a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, modules or indirect coupling or communication connection of modules, which can be electrical or other forms.

[0151] The modules described above as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0152] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0153] If the above-mentioned integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable non-volatile storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a non-volatile storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the various embodiments of the present invention. The aforementioned non-volatile storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0154] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A digital pulse reconstruction method, characterized in that: include: The gamma rays are measured based on the radiation detector to obtain an initial impulse response with a certain amplitude; converting the initial impulse response into a double exponential decay pulse with a time constant; acquiring a single exponential pulse associated with the time constant; The single exponential pulse is convolved with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

2. The digital pulse reconstruction method according to claim 1, characterized in that: The step of converting the initial impulse response into a double exponential decay pulse with a time constant comprises: Based on a first circuit connected to the radiation detector, converting the initial impulse response into a decaying exponential pulse with a time constant, wherein the first circuit includes at least a resistor and a capacitor; Based on the second circuit connected to the first circuit, the decaying exponential pulse is converted into a double exponential decaying pulse, wherein the double exponential decaying pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b .

3. The digital pulse reconstruction method according to claim 2, characterized in that: In the case where the decaying exponential pulse is converted into a time-continuous double exponential decaying pulse through the second circuit, the method further includes: Based on a high-speed analog-to-digital converter, the time-continuous double exponential decay pulse is quantized and encoded to obtain a discrete double exponential decay pulse.

4. The digital pulse reconstruction method according to claim 1, characterized in that: The obtaining of a single exponential pulse associated with the time constant comprises: The double exponential decay pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b In the case of A (n) and the second index pulse h B (n); The first index pulse h A (n) are as follows: Where △T is the signal sampling frequency; τ a is the signal rising edge decay time constant; The second index pulse h B (n) are as follows: Where △T is the signal sampling frequency; τ b is the signal falling edge decay time constant.

5. The digital pulse reconstruction method according to claim 4, characterized in that: The convolving the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude includes: Based on the double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The effect on the double exponential decay pulse results in a convolved pulse; Based on the convolution pulse and the second exponential pulse h B (n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The effect of a double exponential decay pulse is used to obtain the reconstructed impulse response.

6. The digital pulse reconstruction method according to claim 5, characterized in that: The double exponential decay pulse and the first exponential pulse h A (n) Perform convolution to remove the signal rising edge decay time constant τ a The effect on the double exponential decay pulse, resulting in a convolution pulse, includes: The double exponential decay pulse includes a signal rising edge decay time constant τ a The first decay pulse and the decay time constant τ of the falling edge of the signal b The second decay pulse; The convolution pulse is as follows: y A (n)=[x A (n)-x B (n)]*h A (n) Among them, y A (n) is the convolution pulse, x A (n) is the first decay pulse, x B (n) is the second decay pulse, h A (n) is the first index pulse.

7. The digital pulse reconstruction method according to claim 5, characterized in that: The convolution pulse and the second exponential pulse h B (n) Perform convolution to remove the decay time constant τ of the falling edge of the signal b The impact of the double exponential decay pulse to obtain the reconstructed impulse response includes: The reconstructed impulse response is as follows: y(n)={[x A (n)-x B (n)]*h A (n)}*h B (n) Where y(n) is the reconstructed impulse response, x A (n) is the first decay pulse, x B (n) is the second decay pulse, h B (n) is the second index pulse.

8. The digital pulse reconstruction method according to claims 1 to 7, characterized in that: The method further comprises: The reconstructed impulse response is used as an input to a digital pulse shaping algorithm, and the amplitude of the reconstructed impulse response is counted to obtain the number of pulse amplitudes; Based on the number of pulse amplitudes, forming energy spectrum data; The energy spectrum data is displayed on a terminal.

9. A digital pulse reconstruction system, characterized in that: include: A radiation detector, used to measure gamma rays and obtain an initial impulse response with a certain amplitude; a signal conditioning circuit, connected to the radiation detector, for converting the initial impulse response into a time-continuous double exponential decay pulse; a high-speed analog-to-digital converter, connected to the signal conditioning circuit, for converting the time-continuous double exponential decay pulse into a discrete double exponential decay pulse; An FPGA digital signal processing module is connected to the high-speed analog-to-digital converter and is used to perform convolution processing on the discrete double exponential decay pulse and input it into a digital pulse shaping algorithm to obtain energy spectrum data; The terminal is connected to the FPGA digital signal processing module and is used to display the energy spectrum data.

10. The digital pulse reconstruction system according to claim 9, characterized in that: The signal conditioning circuit comprises: A first circuit, connected to the radiation detector, for converting the initial impulse response into a decaying exponential pulse with a time constant, wherein the first circuit at least includes a resistor and a capacitor; The second circuit is connected to the first circuit and is used to convert the decaying exponential pulse into a double exponential decaying pulse, wherein the double exponential decaying pulse includes a signal rising edge decay time constant τ a And the signal falling edge decay time constant τ b .

11. A digital pulse reconstruction device, characterized in that: include: A measurement module, used for measuring gamma rays based on a radiation detector to obtain an initial impulse response with a certain amplitude; A conversion module, used for converting the initial impulse response into a double exponential decay pulse with a time constant; A determination module, configured to obtain a single exponential pulse associated with the time constant; A convolution module is used to convolve the single exponential pulse with the double exponential decay pulse to obtain a reconstructed impulse response with a certain amplitude, wherein the convolution is used to remove the influence of the time constant on the double exponential decay pulse, and the amplitude of the reconstructed impulse response is the same as the amplitude of the initial impulse response.

12. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing a digital pulse reconstruction method as described in any one of claims 1 to 8.

13. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of a digital pulse reconstruction method as claimed in any one of claims 1 to 8 are implemented.

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