A method for processing electronic signals of anti-Kang spectrometer

Abstract

An embodiment of the present application discloses a method for processing electronic signals of an anti-Compton spectrometer, comprising: obtaining a first signal formed after a gamma ray enters a main detector, and a second signal formed after a gamma ray escapes from the main detector and enters an auxiliary detector; according to the formation time of the signals, with the signal output by the first signal after passing through a first delay stretcher as a start signal, and the signal output by the second signal after passing through a second delay stretcher as an end signal, converting the signal time difference between the two signals into a pulse amplitude value of a pulse signal to obtain a pulse amplitude value to form a time pulse amplitude spectrum; based on the time pulse amplitude spectrum, obtaining a target time difference; based on the target time difference, performing time alignment processing on the first signal and the second signal; performing logic operation processing on the two time-aligned signals to obtain a gate-off signal when the gamma ray deposits energy in both the main detector and the auxiliary detector, so that the anti-Compton spectrometer obtains an optimal Compton suppression factor.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a method for processing electronic signals of an anti-Kang spectrometer. Background Art

[0002] Anti-Compton spectrometers can effectively reduce the Compton background caused by Compton scattering. They can also effectively suppress single and double escape peaks in high-energy gamma (γ) ray measurements, improving the measurement accuracy of parameters related to gamma ray measurements characterized by the total energy peak. They are widely used in high-spin nuclear structure research, nuclide analysis, environmental sample measurement, and radiation contamination investigations. The most important performance parameter of an anti-Compton spectrometer is the Compton suppression factor; a larger Compton suppression factor indicates better suppression of the Compton scattering background. The better the temporal alignment of the signals generated by the primary and auxiliary detectors, the greater the performance of the anti-Compton spectrometer.

[0003] In the related art, the method of aligning the signal generated by the main detector and the signal generated by the auxiliary detector in time is generally completed using the delay stretcher GG8020 and an oscilloscope. However, since the time length required for gamma rays to enter the signal generated by the main detector is not a fixed value, and the time length required for gamma rays to enter the signal generated by the auxiliary detector is also not a fixed value, the time interval between the two signals is even more not a fixed value. When using an oscilloscope to "align" the two signals coming out of the delay stretcher, the other signal drifts unpredictably relative to the trigger signal. Therefore, it is difficult to quickly and accurately align the two signals in time using an oscilloscope alone. Summary of the Invention

[0004] The embodiment of the present application provides a method for processing electronic signals of an anti-Kam spectrometer.

[0005] The technical solution of this application is achieved as follows:

[0006] The present application provides a method for processing electronic signals of an anti-Kang spectrometer, the method comprising:

[0007] obtaining a first signal formed when a gamma ray enters a main detector and a second signal formed when a gamma ray escapes from the main detector and enters an auxiliary detector;

[0008] According to the formation time of the signals, with the signal output by the first signal after passing through the first delay stretcher as the start signal and the signal output by the second signal after passing through the second delay stretcher as the end signal, the signal time difference between the two signals is converted into a pulse amplitude value of a pulse signal proportional to the signal time difference, so as to obtain a pulse amplitude spectrum at the formation time of the pulse amplitude value;

[0009] obtaining a target time difference between the first signal and the second signal based on the temporal pulse amplitude spectrum;

[0010] performing time alignment processing on the first signal and the second signal based on the target time difference;

[0011] The two time-aligned signals are subjected to logic operation processing to obtain a gate-off signal when the gamma ray deposits energy on both the main detector and the auxiliary detector, so that the anti-Compton spectrometer obtains an optimal Compton suppression factor.

[0012] The electronic signal processing method of the anti-Compton spectrometer provided in the embodiment of the present application obtains a first signal formed after the gamma ray enters the main detector, and a second signal formed after the gamma ray escapes from the main detector enters the auxiliary detector; according to the formation time of the signal, the signal output by the first signal after passing through the first delay stretcher is used as the start signal, and the signal output by the second signal after passing through the second delay stretcher is used as the end signal, the signal time difference between the two signals is converted into a pulse amplitude value of a pulse signal proportional to the signal time difference, so as to obtain a pulse amplitude value to form a time pulse amplitude spectrum; based on the time pulse amplitude spectrum, the target time difference between the first signal and the second signal is obtained; based on the target time difference, the first signal and the second signal are time-aligned; further, the two signals after time alignment are subjected to logical operation processing to obtain a gate-off signal when the gamma ray deposits energy in both the main detector and the auxiliary detector, so that the anti-Compton spectrometer obtains the best Compton suppression factor; in this way, on the basis of realizing the anti-Compton function of the anti-Compton spectrometer, the best Compton suppression factor is obtained, and the physical background is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 An electronic block diagram of the gamma ray measurement system of the anti-Kang spectrometer provided in an embodiment of the present application;

[0014] Figure 2 A flow chart of a method for processing electronic signals of an anti-Kan spectrometer provided in an embodiment of the present application;

[0015] Figure 3 A time pulse amplitude spectrum of the time interval between the first signal and the second signal provided in an embodiment of the present application;

[0016] Figure 4 A schematic diagram of the waveform positions of an undelayed signal to be delayed and a reference signal provided in an embodiment of the present application;

[0017] Figure 5 A schematic diagram of the waveform positions of a delayed signal to be delayed and a reference signal provided in an embodiment of the present application;

[0018] Figure 6This is a block diagram of the electronics for measuring the time interval spectrum of a high-purity germanium signal and a bismuth germanate signal provided in an embodiment of the present application;

[0019] Figure 7 A schematic diagram of the relationship between the signal of high-purity germanium passing through the main amplifier and the gate signal provided by an embodiment of the present application;

[0020] Figure 8 Schematic diagram of the pulse amplitude spectrum of gamma rays emitted by Co-60 without using back-contact measurement and with using back-contact measurement provided in the embodiments of the present application. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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 this application.

[0022] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0023] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] In order to better understand the electronic signal processing method of the anti-Kang spectrometer provided in the embodiments of the present application, the background technology and related technologies are first described.

[0025] In precise gamma-ray measurements, it is desirable to obtain the lowest possible background signal in the pulse amplitude spectrum used for analysis. This background mainly consists of two components: the background present in the measurement environment, such as radiation from naturally occurring radioactive isotopes and cosmic rays; and the physical background, which is generated by the interaction of gamma rays with the detector, including Compton scattering background, single escape peak background, and double escape peak background, when full-energy peaks are used to label physical parameters. When full-energy peaks are used to label physical parameters, the anti-Compton method is often used to reduce the Compton scattering background. The basic principle is that when the energy of gamma rays is not fully deposited in the sensitive region of the primary detector, an auxiliary detector can be placed outside the primary detector's sensitive region to measure Compton scattered photons and escape photons resulting from positron-electron annihilation. When the auxiliary detector detects a signal from an escape photon, the corresponding event is not recorded in the primary detector. This suppresses the Compton scattering background, single escape peak background, and double escape peak background, thereby reducing the physical background.

[0026] During the use of the anti-Kang spectrometer, it is necessary to adjust the electronics to realize the function of the anti-Kang spectrometer. Here, the electronic block diagram of the anti-Kang spectrometer measuring gamma rays is as follows Figure 1 As shown. Figure 1 As shown, the electronic block diagram 100 includes a main detector 101, an auxiliary detector 102, a first fast amplifier 103, a second fast amplifier 104, a first constant ratio timer 105, a second constant ratio timer 106, a first delay stretcher 107, a second delay stretcher 108, a logic operator 109, a main amplifier 110, a multi-channel analyzer 111, and a data acquisition system 112. Among them:

[0027] The main detector 101 is used to measure the energy of electrons generated by gamma rays and deposited in the detector to obtain a first signal formed by the gamma rays; the auxiliary detector 102 is used to measure a second signal formed by gamma rays escaping from the main detector; wherein, the first signal mentioned in this embodiment and subsequent embodiments is the signal output by the main detector after the gamma rays enter the main detector, and the second signal is the signal output by the auxiliary detector after the gamma rays escape from the main detector and enter the auxiliary detector.

[0028] The first fast amplifier 103 is used to rapidly amplify the first signal; the second fast amplifier 104 is used to rapidly amplify the second signal; the first constant fraction timer 105 is used to determine a first time point corresponding to a first amplitude value of a signal output after the first signal is rapidly amplified, wherein the first time point is the formation time of the first signal; the second constant fraction timer 106 is used to determine a second time point corresponding to a second amplitude value of a signal output after the second signal is rapidly amplified, wherein the second time point is the formation time of the second signal; the first amplitude value is an amplitude value corresponding to the product of the maximum amplitude value of the signal output by the first fast amplifier 103 and a preset ratio; the second amplitude value is an amplitude value corresponding to the product of the maximum amplitude value of the signal output by the second fast amplifier 104 and the preset ratio.

[0029] The first delay stretcher 107 is used to adjust the time width and time point of the first signal output by the first constant ratio timer 105; the second delay stretcher 108 is used to adjust the time width of the second signal output by the second constant ratio timer 106; and the logic operator 109 is used to perform logical operations on the two signals, the signal output by the first delay stretcher 107 and the signal output by the second delay stretcher 108.

[0030] The main amplifier 110 is used to amplify the first signal; the multi-channel analyzer 111 is used to perform amplitude analysis on the signal output by the main amplifier 110, and the gate signal output by the logic operator 109 is used to control whether the multi-channel analyzer outputs a signal, and outputs the signal output by the multi-channel analyzer to the data acquisition system 112 to obtain the pulse amplitude spectrum of the anti-conversion measurement.

[0031] However, the most critical step in the electronics of a gamma-ray spectrometer is achieving temporal alignment between the signals generated by the main and auxiliary detectors. In the prior art, this is accomplished using a delay stretcher (GG8020) and an oscilloscope. However, because the time required for a gamma ray to enter the signal generated by the main detector and the signal generated by the auxiliary detector varies, the time interval between the two signals is also not fixed. When using an oscilloscope to "align" the two signals from the delay stretcher, the other signal drifts unpredictably relative to the trigger signal. Therefore, it is difficult to quickly and accurately align the two signals using an oscilloscope alone.

[0032] See also Figure 2 , Figure 2 1 is a schematic diagram of an implementation flow of a method for processing electronic signals of an anti-Kan spectrometer provided in an embodiment of the present application. The method for processing electronic signals of an anti-Kan spectrometer includes the following steps:

[0033] Step 201: Obtain a first signal generated when gamma rays enter a main detector, and a second signal generated when gamma rays escape from the main detector and enter an auxiliary detector.

[0034] In the embodiment of the present application, the main detector is a detector with better resolution. The main detector can be a high-purity germanium detector or a lanthanum bromide detector. This application does not impose any specific restrictions on this.

[0035] Here, when the main detector is a high-purity germanium detector, the high-purity germanium detector includes a high-purity germanium crystal for forming electron-hole pairs; when high voltage is applied to the high-purity germanium crystal and an electric field is formed in the high-purity germanium detector, the gamma rays entering the high-purity germanium detector form electron-hole pairs in the high-purity germanium crystal and are collected as a first signal.

[0036] In the embodiments of the present application, after gamma rays enter the primary detector, some gamma rays fail to deposit all their energy in the primary detector, and some escaping photons enter the auxiliary detector, forming a secondary signal. It should be noted that the auxiliary detector can be a detector with higher detection efficiency, such as a sodium iodide detector or a bismuth germanium oxide detector. When the auxiliary detector is a bismuth germanium oxide detector, the gamma rays generate fluorescence in the bismuth germanium oxide crystal, which then passes through a photomultiplier tube to form a secondary signal.

[0037] In other embodiments of the present application, after obtaining the first signal generated after the gamma ray enters the main detector in step 201, if it is determined that the first signal is an advance signal, the following process may be further performed:

[0038] The first signal and the second signal are respectively subjected to rapid amplification processing; a first time point corresponding to a first amplitude value of a signal output by the first signal after the rapid amplification processing is determined, and a second time point corresponding to a second amplitude value of a signal output by the second signal after the rapid amplification processing is determined; a time width and the first time point of a signal output by the first constant fraction timer of the first signal are adjusted, and a time width of a signal output by the second constant fraction timer of the second signal is adjusted.

[0039] In the embodiment of the present application, the first amplitude value is the amplitude value corresponding to the product of the maximum amplitude value of the signal output by the first signal after rapid amplification processing and the preset ratio. The second amplitude value is the amplitude value corresponding to the product of the maximum amplitude value of the signal output by the second signal after rapid amplification processing and the preset ratio. For example, the preset ratio can be any ratio between 5% and 15%, such as 10%, that is, the first amplitude value is equal to the maximum amplitude value of the signal output by the first signal after rapid amplification processing × 10%. The first time point can be the time point corresponding to the first amplitude value, which can be specifically understood as the time point corresponding to the rising edge of the first amplitude value.

[0040] In an embodiment of the present application, after obtaining the first signal formed after the gamma ray enters the main detector, first, the first signal is input into a first fast amplifier, and the first signal is rapidly amplified to obtain a signal output by the first signal after the rapid amplification processing; and the second signal is input into a second fast amplifier, and the second signal is rapidly amplified to obtain a signal output by the second signal after the rapid amplification processing; in this way, by rapidly amplifying the first signal and the second signal, the accuracy of the time alignment of the two signals can be improved.

[0041] Then, the signal outputted by the first signal after rapid amplification is inputted into a first constant ratio timer, which determines a first time point corresponding to a first amplitude value of the signal outputted by the first signal after rapid amplification; and the signal outputted by the second signal after rapid amplification is inputted into a second constant ratio timer, which determines a second time point corresponding to a second amplitude value of the signal outputted by the second signal after rapid amplification. Finally, the signal outputted by the first constant ratio timer is inputted into a first delay stretcher, which adjusts the time width and the first time point of the signal outputted by the first constant ratio timer; and the signal outputted by the second constant ratio timer is inputted into a second delay stretcher, which adjusts the time width of the signal outputted by the second constant ratio timer.

[0042] Generally speaking, the GG8020 delay stretcher has eight channels. One channel, designated the first channel, can be used to input the first signal, which passes through the first constant fraction timer output. The second channel, designated the second channel, can be used to input the second signal, which passes through the second constant fraction timer output. Using an oscilloscope, adjust the width knob on the first channel to set the time width of the signal output from the first constant fraction timer to 40 nanoseconds (ns). Adjust the width knob on the second channel to set the time width of the signal output from the second constant fraction timer to 300 nanoseconds. To facilitate subsequent electronic adjustments, set the delay knobs on both channels to their minimum values.

[0043] It should be emphasized that in the subsequent execution process, the embodiment of the present application can convert the signal time difference between the two signals into a pulse amplitude value of a pulse signal proportional to the signal time difference according to the signal formation time, with the signal output by the first signal after the delay stretcher as the starting signal and the signal output by the second signal after the delay stretcher as the ending signal, so as to obtain the pulse amplitude spectrum of the pulse amplitude value formation time.

[0044] Step 202: According to the formation time of the signals, with the signal output by the first signal after passing through the first delay stretcher as the start signal and the signal output by the second signal after passing through the second delay stretcher as the end signal, the signal time difference between the two signals is converted into a pulse amplitude value of a pulse signal proportional to the signal time difference, so as to obtain a pulse amplitude spectrum of the pulse amplitude value formation time.

[0045] In the embodiment of the present application, the signal time difference is the time interval between the formation time of the first signal and the formation time of the second signal.

[0046] In the embodiment of the present application, the horizontal axis of the time pulse amplitude spectrum represents the channel address, and the vertical axis represents the count. The channel address is a digital quantity representing the pulse amplitude value. It can be understood that the channel address is the value of one of the channels obtained by equally dividing the preset pulse amplitude value into 1024 channels, 2048 channels, and so on. That is, there is a one-to-one correspondence between the channel address and the amplitude value. The count indicates the number of times each amplitude value occurs in the pulse signal.

[0047] In the embodiment of the present application, the temporal pulse amplitude spectrum is used to characterize the relationship between the channel address and the number of times in the pulse signal, that is, different channel addresses correspond to different pulse amplitude values.

[0048] In an embodiment of the present application, after obtaining a first signal formed after the gamma ray enters the main detector and a second signal formed after the gamma ray escapes from the main detector and enters the auxiliary detector, the signal of the first signal after passing through the delay stretcher and the signal of the second signal after passing through the delay stretcher are input into the time-to-amplitude converter. The time-to-amplitude converter converts the signal time difference between the two signals into a pulse amplitude value of a pulse signal proportional to the signal time difference according to the formation time of the signals, with the signal output by the first signal after passing through the first delay stretcher as the start signal and the signal output by the second signal after passing through the second delay stretcher as the end signal, so as to obtain a pulse amplitude spectrum of the pulse amplitude value formation time.

[0049] Step 203: Obtain a target time difference between the first signal and the second signal based on the time pulse amplitude spectrum.

[0050] In some embodiments, step 203 of obtaining a target time difference between the first signal and the second signal based on the temporal pulse amplitude spectrum may be implemented by the following steps:

[0051] Step 231: In the time pulse amplitude spectrum, determine the track address corresponding to the count peak as the target track address.

[0052] In the embodiment of the present application, the counting peak value refers to the maximum counting value.

[0053] In a feasible application scenario, refer to Figure 3As shown in the figure, after converting the signal time difference into a pulse amplitude value proportional to the signal time difference, a time pulse amplitude spectrum is generated to represent the time interval between the first and second signals. The horizontal axis of the time pulse amplitude spectrum represents the signal channel address, and the vertical axis represents the counts corresponding to the channel address. In this time pulse amplitude spectrum, the channel address corresponding to the count peak is determined as the target channel address. In this case, the target channel address is channel 259, meaning that the channel address at the count peak represents the most probable signal time difference or time interval.

[0054] Step 232: Based on the total number of track addresses and the time window width, a target time difference corresponding to the target track address is determined using a calculation formula of track address and time.

[0055] The calculation formula of the address and time can be expressed by the following formula (1):

[0056]

[0057] Where t represents time, n represents the channel address, N represents the total number of channels, and T represents the time window width.

[0058] In the embodiment of the present application, the total number of channel addresses N and the time window width T in formula (1) are manually set when measuring the temporal pulse amplitude spectrum. After determining the target channel address, the target channel address is substituted into the channel address and time calculation formula to obtain the target time difference corresponding to the target channel address, also known as the most probable time interval. In this way, using the time-to-amplitude converter plug-in to measure the temporal pulse amplitude spectrum of two signals provides accurate delay time data for temporally aligning the two signals using an oscilloscope, thereby accurately delaying the first signal by the corresponding time, thereby fully utilizing the Compton scattering background suppression function of the anti-Compton spectrometer.

[0059] Here, continue to refer to Figure 3 As shown, the total number of channels N is 1024, and the time interval between the two signals exhibits a certain time distribution. The target channel corresponding to the count peak is channel 259. The time window width T used is 500 nanoseconds, that is, 50 × 10 nanoseconds. Therefore, the time block selected on the time-to-amplitude converter plug-in is 50 nanoseconds, and the multiplier is 10. Therefore, the target time difference corresponding to the target channel can be calculated using formula (2), resulting in a target time difference of 126 nanoseconds.

[0060]

[0061] Where t represents the target time difference and n represents the target address.

[0062] Step 204: Perform time alignment processing on the first signal and the second signal based on the target time difference.

[0063] In some embodiments, step 204 of performing time alignment processing on the first signal and the second signal based on the target time difference may be implemented as follows:

[0064] In the case where the first signal is determined to be the leading signal, a delay process is performed on the first signal based on the target time difference to ensure that the first signal and the second signal are aligned in time.

[0065] Here, the delay processing of the first signal based on the target time difference can be implemented as follows:

[0066] Step 240, performing fast amplification processing on the first signal through a fast amplifier;

[0067] Step 241: Process the output signal of the first signal after rapid amplification processing into two identical first sub-signals and second sub-signals after passing through a timing module;

[0068] Step 242 , determining that one of the first sub-signal and the second sub-signal is a reference signal and the other is a signal to be delayed;

[0069] Step 243: Using the reference signal as a reference, the signal to be delayed is connected to the time delay module of the main detector circuit of the anti-Kang spectrometer for time alignment;

[0070] Step 244 : Delay the signal to be delayed by a target time difference via a time delay module.

[0071] In an embodiment of the present application, after determining the target time difference and determining that the leading signal is the first signal, the first signal passing through the constant ratio timer is processed using a three-way channel into two identical signals, namely, a first sub-signal and a second sub-signal, and one of the first sub-signal and the second sub-signal is determined to be a reference signal and the other is a signal to be delayed; further, with the reference signal as a reference, the signal to be delayed is delayed by the target time difference.

[0072] Here, continue to refer to Figure 3As shown, after determining that the first signal is the leading signal, the most probable time difference between the first and second signals, or the target time difference, is determined to be 126 nanoseconds. Therefore, the first signal needs to be delayed "backward" by 126 nanoseconds. To delay the first signal backward by 126 nanoseconds, a reference signal is required. Obviously, using a second signal, which is not the first signal, as the reference signal is inappropriate. In this case, the first signal needs to be split into two signals using a three-way connection after passing through a constant ratio timer. One signal serves as the reference signal, and the other as the signal to be delayed. These signals are then connected to different independent modules of the delay stretcher (i.e., delay stretching modules). The delay stretching module for the signal to be delayed and the delay stretching module for the high-purity germanium signal of the spectrometer are on the same channel of the delay stretcher GG8020 and pass through different channels of the oscilloscope. Since both the reference signal and the signal to be delayed are generated by the same detector, the time interval between the reference signal and the signal to be delayed is fixed.

[0073] Figure 4 FIG. 1 is a schematic diagram showing the waveform positions of the undelayed signal to be delayed and the reference signal, wherein: Figure 4 In the figure, the dotted, thicker line represents the signal to be delayed, and the solid, thinner line represents the reference signal. In actual application, when the target time difference is 126 nanoseconds, the signal to be delayed is delayed by 126 nanoseconds by turning the delay knob of the high-purity germanium path used for back-conversion measurement in the delay stretcher. The time relationship between the two signals after the delay is as follows: Figure 5 As shown, Figure 5 Shown is a schematic diagram of the waveform positions of the delayed signal to be delayed and the reference signal.

[0074] From the above, it can be seen that after determining the target time difference, the signal to be delayed is delayed by the target time difference with the reference signal as a reference. Since the delay stretching module used to delay the first signal and the delay stretching module used for the high-purity germanium path signal of the anti-Compton spectrometer are the same path of the delay stretcher GG8020, that is, the high-purity germanium path signal of the anti-Compton spectrometer is delayed by the target time difference, the alignment of the first signal and the second signal is finally achieved, and then the electronics of the anti-Compton spectrometer are adjusted to obtain the best Compton suppression factor and reduce the physical background.

[0075] Step 205 : Performing logic operation on the two time-aligned signals to obtain a gate-off signal when gamma rays deposit energy in both the main detector and the auxiliary detector, so that the anti-Compton spectrometer obtains an optimal Compton suppression factor.

[0076] In some embodiments, when gamma rays deposit energy on the primary detector but not on the auxiliary detector, that is, only the first signal exists but not the second signal after time alignment, an open gate signal of the signal recorded by the primary detector is obtained.

[0077] Here, if both the first and second signals are present after time alignment, a gate-off signal is generated to ensure that the main detector does not record gamma-ray energy. If only the first signal is present and the second signal is absent after time alignment, a gate-on signal is generated to ensure that the main detector records the signal. In this way, by setting a gate signal to determine whether the main detector records gamma-ray energy, the anti-Compton spectrometer achieves the optimal Compton suppression factor, reducing the physical background.

[0078] Figure 6 What is shown is an electronic block diagram for measuring the time interval spectrum of a high-purity germanium signal and a bismuth germanate signal. The electronic block diagram 600 includes a high-purity germanium detector 601, a bismuth germanate detector 602, a first fast amplifier 103, a second fast amplifier 104, a first constant ratio timer 105, a second constant ratio timer 106, a first delay stretcher 107, a second delay stretcher 108, a time-to-amplitude converter 603, a multi-channel analyzer 111 and a data acquisition system 112.

[0079] Among them, the high-purity germanium detector 601 is used to measure the high-purity germanium signal formed by gamma rays, and the bismuth germanate detector 602 is used to measure the bismuth germanate signal formed by gamma rays escaping from the high-purity germanium detector 601; the first fast amplifier 103 is used to quickly amplify the high-purity germanium signal to obtain a signal output by the high-purity germanium signal after the rapid amplification processing; the second fast amplifier 104 is used to quickly amplify the bismuth germanate signal to obtain a signal output by the bismuth germanate signal after the rapid amplification processing; the first constant ratio timer 105 is used to determine a first time point corresponding to a preset ratio of the maximum amplitude value of the signal output by the high-purity germanium signal after the rapid amplification processing; the second constant ratio timer 106 is used to determine a second time point corresponding to a preset ratio of the maximum amplitude value of the signal output by the bismuth germanate signal after the rapid amplification processing; the first delay stretcher 107 is used to adjust the time width and the first time point of the signal output by the high-purity germanium signal after the first constant ratio timer 105 if the signal output by the high-purity germanium signal after the first constant ratio timer 105 is an advanced signal; the second delay stretcher 108 is used to adjust the time width of the signal output by the bismuth germanate signal after the second constant ratio timer 106;

[0080] The time-to-amplitude converter 603 converts the time difference between the high-purity germanium signal output after the first delay stretcher 107 and the bismuth germanium oxide signal output after the second delay stretcher 108 into a pulse amplitude proportional to the signal time difference, based on the signal formation time. The multi-channel analyzer 111 analyzes the pulse amplitude values, converts different pulse amplitude values ​​into different channel addresses, and outputs them to the data acquisition system 112 to form a time pulse amplitude spectrum.

[0081] In an embodiment of the present application, the time-to-amplitude converter 603 converts the signal time difference between the two signals into a pulse amplitude value, and based on the pulse amplitude value, obtains a time pulse amplitude spectrum of the time difference between the two signals; in the time pulse amplitude spectrum, the channel address corresponding to the counting peak is determined as the target channel address, and the target time difference corresponding to the target amplitude value; and then, when the high-purity germanium signal is determined to be an advanced signal, the high-purity germanium signal is delayed by the above-mentioned target time difference by adjusting the delay module of the delay stretcher corresponding to the high-purity germanium signal, and finally the time alignment of the high-purity germanium signal and the bismuth germanate signal is achieved, and then the anti-Compton spectrometer electronics is adjusted to realize the anti-Compton spectrometer function, and the optimal Compton suppression factor can be obtained, thereby reducing the physical background.

[0082] Here, continue to refer to Figure 1 As shown, taking a high-purity germanium detector as the main detector and a bismuth germanate detector as the auxiliary detector as an example, the high-purity germanium detector (main detector 101), main amplifier 110, multi-channel analyzer 111, and data acquisition system 112 constitute the first circuit. The first circuit is used to measure the signal of gamma ray energy deposition in the high-purity germanium detector 101.

[0083] The second circuit comprises a high-purity germanium detector 101, a bismuth germanate detector (auxiliary detector 102), a first fast amplifier 103, a second fast amplifier 104, a first constant fraction timer 105, a second constant fraction timer 106, a first delay stretcher 107, a second delay stretcher 108, and a logic operator 109. This second circuit provides a gate signal for the high-purity germanium detector 101 in the first circuit to measure gamma rays, ensuring that the high-purity germanium detector 102 records only the full-energy peak signal as much as possible.

[0084] For example, when both the high-purity germanium detector 101 and the bismuth germanium oxide detector 102 in the second part of the circuit have signals, a closing signal is provided, and the non-full-energy peak signal in which only part of the gamma-ray energy is deposited in the high-purity germanium detector 101 is not recorded; when only the high-purity germanium detector 101 in the second part of the circuit has a signal, and the bismuth germanium oxide detector 102 has no signal, an opening signal is provided, and at this time the full-energy peak signal containing all the energy deposited by the gamma rays in the high-purity germanium detector is recorded.

[0085] Here, the high-purity germanium signal in the second circuit serves as the lead signal. After delaying the high-purity germanium signal, the signal output by the high-purity germanium signal after passing through the first delay stretcher 107 and the signal output by the bismuth germanium oxide signal after passing through the second delay stretcher 108 are connected to a logic operator 109. After operation, a gate signal is generated. The operation rule is as follows: if the high-purity germanium signal and the bismuth germanium oxide signal are present in the second circuit, a gate-close signal is output; if the high-purity germanium signal and the bismuth germanium oxide signal are absent in the second circuit, a gate-open signal is output.

[0086] The relationship between the signal of the high purity germanium detector after the main amplifier and the gate signal is as follows Figure 7 As shown by Figure 7 It can be seen that the signal is exactly within the gate signal, indicating that the high-purity germanium signal and the bismuth germanate signal are aligned, and the adjustment of the anti-Compton spectrometer electronics has been achieved, which can obtain the best Compton suppression factor, thereby reducing the physical background. At this time, the Compton suppression factor of the anti-Compton spectrometer is measured using the adjusted anti-Compton spectrometer electronics. The anti-Compton effect diagram is shown in the figure below. Figure 8 As shown, Figure 8 The pulse amplitude spectra of gamma rays emitted by Co-60 without and with back-Conton measurement are shown. One is the pulse amplitude spectrum obtained by non-back-Conton measurement, and the other is the pulse amplitude spectrum obtained by back-Conton measurement. If the counts in the Compton platform region (i.e., the low energy part: the low channel address part) of the back-Conton measurement are lower, it proves that the back-Conton effect is better. Here, the definition of peak-to-Compton ratio and Compton suppression factor is that when the radioactive source Co-60 is used to perform Compton suppression factor measurement, the "peak" in the peak-to-Compton ratio refers to the peak height of the 1.3325 MeV full energy peak, and the "Compton" in the peak-to-Compton ratio refers to the average count per channel in the Compton platform (1.04 to 1.096) MeV energy region. The calculation formulas for the peak-to-Compton ratio are shown in formula (3) and the calculation formula for the Compton suppression factor are shown in formula (4):

[0087]

[0088]

[0089] Accordingly, the data used for the Compton suppression factor measurement are shown in Table 1 , which is a parameter table for the calculation of the Compton suppression factor of the inverse Compton spectrometer, and quantitatively illustrates the effect of the inverse Compton measurement.

[0090] Table 1

[0091] 1332.5keV peak height counts when anti-coincidence measurement is not used 3993 Average counts per channel of the (1040-1096)keV Compton platform when anti-coincidence measurement is not used 88.8 1332.5keV peak height counts when using anti-coincidence measurement 3899 Average counts per channel of the (1040-1096)keV Compton platform when using anti-coincidence measurement 23.4 Compton inhibitory factor 3.70

[0092] From the above, it can be seen that by measuring the time pulse amplitude spectrum of the two signals, the distribution spectrum of the time interval (also known as the signal time difference) of the two signals is obtained, and the most probable position of the time distribution is determined; the most probable time difference, that is, the target time difference, is calculated according to the target channel address, the total number of channels, and the width of the time window; then the high-purity germanium signal is delayed by the target time difference, and the electronics of the spectrometer are smoothly and accurately adjusted.

[0093] It should be noted that, for the description of the same steps and contents in this embodiment as those in other embodiments, reference can be made to the description in other embodiments and will not be repeated here.

[0094] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0095] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0096] In addition, all functional units in the embodiments of the present application can be integrated into one processing module, or each unit can be a separate unit, or two or more units can be integrated into one unit; the above-mentioned integrated units can be implemented in the form of hardware or in the form of hardware plus software functional units.

[0097] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined, if they do not conflict, to obtain new method embodiments. The features disclosed in the several product embodiments provided in this application can be arbitrarily combined, if they do not conflict, to obtain new product embodiments. The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined, if they do not conflict, to obtain new method embodiments or device embodiments.

[0098] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for processing electronic signals of an anti-Kang spectrometer, characterized in that: The method comprises: obtaining a first signal formed when a gamma ray enters a main detector and a second signal formed when a gamma ray escapes from the main detector and enters an auxiliary detector; According to the formation time of the signals, with the signal output by the first signal after passing through the first delay stretcher as the start signal and the signal output by the second signal after passing through the second delay stretcher as the end signal, the signal time difference between the two signals is converted into a pulse amplitude value of a pulse signal proportional to the signal time difference, so as to obtain a pulse amplitude spectrum at the formation time of the pulse amplitude value; Based on the time pulse amplitude spectrum, obtaining a target time difference between the first signal and the second signal, wherein the target time difference is a time difference corresponding to a count peak in the time pulse amplitude spectrum; performing time alignment processing on the first signal and the second signal based on the target time difference; Performing logic operation on the two time-aligned signals to obtain a gate-off signal when the gamma ray deposits energy on both the main detector and the auxiliary detector, so that the anti-Compton spectrometer obtains an optimal Compton suppression factor; The performing time alignment processing on the first signal and the second signal based on the target time difference includes: In the case where it is determined that the first signal is an advanced signal, the first signal is rapidly amplified by a fast amplifier; Processing the signal outputted from the first signal after rapid amplification processing into two identical first sub-signals and a second sub-signal after passing through a timing module; Determining that one of the first sub-signal and the second sub-signal is a reference signal and the other is a signal to be delayed; Using the reference signal as a reference, the signal to be delayed is connected to a time delay module of a main detector circuit of the anti-Kang spectrometer for time alignment; The signal to be delayed is delayed by the target time difference through the time delay module to ensure that the first signal and the second signal are aligned in time.

2. The electronic signal processing method of the anti-Kang spectrometer according to claim 1, characterized in that: The horizontal axis data of the time pulse amplitude spectrum is the channel address, and the vertical axis data is the count; The obtaining, based on the time pulse amplitude spectrum, a target time difference between the first signal and the second signal, comprises: In the time pulse amplitude spectrum, determining the track address corresponding to the count peak as the target track address; Based on the total number of track addresses and the time window width, the target time difference corresponding to the target track address is determined using a calculation formula of track address and time.

3. The electronic signal processing method of the anti-Kang spectrometer according to claim 2, characterized in that: The calculation formula of the address and time is: in, t Indicates time, n Indicates the road address, N Indicates the total number of addresses. T Indicates the time window width.

4. The electronic signal processing method of the anti-Kang spectrometer according to claim 1, characterized in that: The method further comprises: When the gamma ray deposits energy on the main detector but not on the auxiliary detector, that is, when only the first signal exists but the second signal does not exist after time alignment, an open gate signal of the signal recorded by the main detector is obtained.

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