A method for pseudo-peak correction based on pulse repair

Abstract

The present invention discloses a pseudo-peak correction method based on pulse repair, which mainly solves the problems of pulse mutation caused by frequent switch reset of the switched-reset preamplifier circuit and pseudo-peaks caused by the mutation. The method mainly includes the following steps: obtaining a weak current signal output by the preamplifier circuit, converting the signal through a differential circuit to obtain a negative exponential signal V n ; amplifying the negative exponential signal V n , with the amplified amplitude range being 0 - 2V, and then performing analog-to-digital conversion on the amplified negative exponential signal to obtain a negative exponential pulse sequence V 1n ; by judging the sampling points of the negative exponential pulse sequence V 1n , when a sampling point of zero appears, mark the pulse as a mutant pulse, and call the optimal repair algorithm to repair the mutant pulse to obtain a repaired negative exponential pulse sequence V 2n ; performing digital ladder shaping on the negative exponential signal V 2n and storing the shaping result in a FIFO; performing multi-channel spectrum formation on the shaping result.

Description

Technical Field

[0001] The present invention relates to the field of signal processing, and more particularly, to a method for correcting pseudo-peaks based on pulse repair. Background Art

[0002] Frequent resetting of the switched-reset preamplifier integrated in the semiconductor detector results in the generation of a large number of mutant pulses. If these mutant pulses are not removed or repaired, they will exist in the form of pseudo-peaks in front of the full-energy peak in the finally obtained spectrum, seriously affecting the discrimination of characteristic peaks of trace elements in energy spectrum analysis and also reducing the counting rate of characteristic peaks.

[0003] The currently commonly used method for processing pseudo-peaks is to directly remove the mutant pulses. Although this method can achieve the purpose of eliminating pseudo-peaks, it also has the defect of counting rate loss.

[0004] Therefore, it is necessary to propose a pseudo-peak correction method that is simple to calculate and can ensure the counting rate while eliminating pseudo-peaks. Summary of the Invention

[0005] In view of this, the purpose of the embodiments of the present invention is to provide a method for correcting pseudo-peaks based on pulse repair, which is mainly used to solve the problem of counting rate loss existing in the prior art.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] First step, obtain the weak current signal output by the preamplifier circuit, and convert this signal through a differential circuit to obtain a negative exponential signal V n ;

[0008] Second step, amplify and digitize the negative exponential signal V n to obtain a negative exponential pulse sequence V 1n ;

[0009] (1) Amplify the negative exponential signal V n , and the amplified amplitude range is 0 - 2V;

[0010] (2) Perform analog-to-digital conversion on the amplified negative exponential signal to obtain a negative exponential pulse sequence V 1n ;

[0011] Third step, repair the negative exponential pulse sequence V 1n to obtain a repaired negative exponential pulse sequence V 2n , specifically as follows:

[0012] (1) Establish a theoretical calculation formula for pulse repair, and its expression is

[0013] Recursive formula of the first-order successive approximation method:

[0014]

[0015] Recursive formula of the second-order successive approximation method:

[0016]

[0017] ……

[0018] Recursive formula of the seventh-order successive approximation method:

[0019]

[0020] In the above recursive formula of the successive approximation method, the higher the order, the slower the attenuation rate of the curve. Among them, the repair result of the seventh-order successive approximation method is the closest to the attenuation trend of the original pulse. Therefore, formula (1-3) is selected as the theoretical formula of the optimal algorithm for pulse repair in the present invention.

[0021] (2) Assume that the negative exponential pulse sequence V 1n loses all sampling points after the nth sampling point;

[0022] (3) By judging the sampling points of the negative exponential pulse sequence V 1n , when a zero sampling point appears, expression (1-3) is called to iteratively repair the sampling points lost by the mutant pulse, and the repaired negative exponential pulse sequence V 2n ;

[0023] In the fourth step, digital ladder shaping is performed on the negative exponential signal V 2n , and the shaping result is stored in the FIFO;

[0024] In the fifth step, multi-channel spectrum formation is performed on the shaping result.

[0025] For the prior art, the pseudo-peak correction method based on pulse repair provided by the present invention has the following beneficial effects:

[0026] (1) The pulse repair method adopted by the present invention repairs the mutant pulse instead of eliminating it, which can ensure that the counting rate is not lost to the greatest extent.

[0027] (2) Moreover, the attenuation trend of the curve repaired by the pulse repair method adopted by the present invention is roughly the same as that of the original negative exponential pulse, and the mutant part of the pulse is repaired to the greatest extent.

[0028] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a flowchart of the pseudo-peak processing method provided by a preferred embodiment of the present invention.

[0031] Figure 2 It is a graph of the mutant negative exponential pulse sequence provided by a preferred embodiment of the present invention.

[0032] Figure 3 It is a graph of the repaired mutant negative exponential pulse sequence provided by a preferred embodiment of the present invention.

[0033] Figure 4 It is the mutant negative exponential pulse and its shaping result provided by a preferred embodiment of the present invention.

[0034] Figure 5 It is the repaired mutant negative exponential pulse and its shaping result provided by a preferred embodiment of the present invention.

[0035] Figure 6 It is the original spectrum measured from the iron-tin-strontium sample provided by a preferred embodiment of the present invention.

[0036] Figure 7 It is the original spectrum of the characteristic peak of iron element in the iron-tin-strontium sample provided by a preferred embodiment of the present invention and the spectrum after repairing the mutant pulse.

[0037] Figure 8 It is the original spectrum of the characteristic peak of strontium element in the iron-tin-strontium sample provided by a preferred embodiment of the present invention and the spectrum after repairing the mutant pulse. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it is not necessary to further define and explain it in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0040] The present invention provides a pseudo-peak correction method based on pulse repair, and the specific implementation is as follows:

[0041] Mutant pulses are an inevitable problem in the switched-reset preamplifier circuit. Especially in the application background with a relatively high counting rate, frequent switching resets will lead to a sharp increase in the number of mutant pulses, resulting in an increase in the counting rate in the pseudo-peak region and a decrease in the counting rate of the elemental characteristic peak. By repairing the mutant pulses, it is possible to correct the counting rate in the pseudo-peak region into the elemental characteristic peak, which can not only eliminate the pseudo-peak but also ensure that the counting rate is not lost.

[0042] As Figure 1 shown, it is a flowchart of the pseudo-peak correction method provided by a preferred embodiment of the present invention. The following will elaborate in detail on Figure 1 the specific process shown.

[0043] Step P1: Obtain the weak current signal output by the preamplifier circuit, and convert this signal through a differentiating circuit to obtain a negative exponential signal V n ;

[0044] Step P2: Amplify and digitize the negative exponential signal V n to obtain a negative exponential pulse sequence V 1n ;

[0045] (1) Amplify the negative exponential signal V n , and the amplified amplitude range is 0 - 2V;

[0046] (2) Perform analog-to-digital conversion on the amplified negative exponential signal to obtain a negative exponential pulse sequence V 1n ;

[0047] Step P3: Repair the negative exponential pulse sequence V 1n to obtain a repaired negative exponential pulse sequence V 2n ;

[0048] In the said step P3, the steps for repairing mutant negative exponential pulses are as follows:

[0049] (1) By judging the sampling points of the negative exponential pulse sequence V 1n , when a sampling point that is zero appears, mark this pulse as a mutant pulse;

[0050] (2) Establish a first-order theoretical formula for pulse repair, derive a general expression for high-order repair from the first-order repair theoretical formula, compare the repair results of each repair expression, and take the expression with the best repair result as the optimal algorithm for pulse repair;

[0051] (3) Call the optimal repair algorithm to repair the mutant pulse in step (1) to obtain a repaired negative exponential pulse sequence V 2n ;

[0052] Step P4, perform digital staircase shaping on the negative exponential signal V 2n and store the shaping result in the FIFO;

[0053] Step P5, perform multi-channel spectral formation on the shaping result.

[0054] As Figure 2 and Figure 3 shown, Figure 2 is the original negative exponential pulse sequence diagram, including a mutant pulse that has lost most of its sampling points. Figure 3 is the negative exponential pulse sequence diagram after repair using the pulse repair expression (1-3) provided in the embodiment of the present invention. Most of the lost sampling points of the repaired mutant pulse have been restored.

[0055] As Figure 4 and Figure 5 shown, Figure 4 is the original negative exponential pulse and its triangular shaping result. Since the negative exponential pulse has lost most of its sampling points, its shaping result has losses in both pulse amplitude and pulse width. Figure 5 is the negative exponential pulse after repair using the pulse repair expression (1-3) provided in the embodiment of the present invention and the shaping result of the repaired mutant pulse. Since most of the lost sampling points of the repaired negative exponential pulse have been restored, its shaping result has been repaired in both pulse width and pulse amplitude.

[0056] As Figure 6 , Figure 7 and Figure 8 shown, Figure 6 is the original spectrum measured from the iron-tin-strontium sample provided by the preferred embodiment of the present invention. The figure mainly contains the characteristic peaks of iron and strontium elements. It can be seen that due to the existence of the mutant pulse, there is a pseudo-peak in front of the characteristic peaks of iron and strontium elements. The present invention defines them as pseudo-peak 1 and pseudo-peak 2.

[0057] Figure 7 and Figure 8 are respectively the K of iron element and strontium element in the iron-tin-strontium sample provided by the preferred embodiment of the present invention αOriginal spectrum of characteristic peaks and comparison chart of the spectrum after correction using the pulse repair method. The comparison of measurement results before and after pseudo-peak correction is shown in Table 1:

[0058] Table 1

[0059]

[0060] Among them, C origin represents the original count rate, and C corrected represents the count rate obtained after correcting the pseudo-peak. D corrected represents the difference in count rate before and after fast correction and slow correction, and E represents the correction efficiency. Its calculation formula is shown in Equation (1-4).

[0061] E = C corrected / C corrected (1-4)

[0062] It can be seen from Table 1 that after correction using the pulse repair method, the counts in the channel address intervals where pseudo-peak 1 and pseudo-peak 2 are located have significantly decreased compared to without correction. At the same time, the counts in the channel address intervals where the two characteristic peaks are located have significantly increased compared to without correction. Therefore, the difference in count rate before and after correction of pseudo-peak 1 and pseudo-peak 2 is always negative, while the difference in count rate of the element characteristic peaks is always positive. Ideally, the decrease value of the count rate in the pseudo-peak region and the increase value of the count rate in the characteristic peak region of the same element should tend to be the same numerically. The difference in count rate of the intervals where the pseudo-peak and the element characteristic peak are located in Table 1 basically conforms to this trend. According to the spectral comparison and analysis, it can be known that pseudo-peak correction can effectively repair the loss of sampling points caused by pulse mutation, so as to achieve the purpose of eliminating pseudo-peaks and ensuring the count rate.

[0063] In several embodiments provided by the present application, it should be understood that the disclosed method can also be implemented in other ways. The above-described embodiments are merely illustrative. For example, the flowcharts and block diagrams in the drawings show the system architecture, functions, and operations that the method according to the present invention may implement. In this regard, each block in the flowchart may represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementation manners, the functions marked in the blocks may occur in a different order than that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved.

[0064] In addition, in each embodiment of the present invention, the functional modules may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0065] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0066] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for pseudo-peak correction based on pulse repair, characterized in that, Including the following steps: P1, obtain the weak current signal output by the preamplifier circuit, convert this signal through a differentiating circuit to obtain a negative exponential signal V n ; P2, amplify and digitize the negative exponential signal V n to obtain a negative exponential pulse sequence V 1n ; P3, repair the negative exponential pulse sequence V 1n to obtain the repaired negative exponential pulse sequence V 2n ; In step P3, the repair process of the negative exponential pulse sequence specifically includes the following steps: P31, by judging the sampling points of the negative exponential pulse sequence V 1n when a sampling point of zero appears, mark the pulse as a mutant pulse; P32. Call the optimal repair algorithm for the mutant pulse in the step P31 to obtain the repaired negative exponential pulse sequence V 2n ; In step P32, the steps for repairing the mutant negative exponential pulse are as follows: P321, establish a first-order theoretical formula for pulse repair; P322, derive a general expression for high-order repair from the first-order repair theoretical formula, and the high-order repair is seventh-order repair, and the general expression for seventh-order repair is: P323, compare the repair results of each repair expression, and take the expression with the best repair result as the optimal algorithm for pulse repair; P4, perform digital ladder shaping on the negative exponential signal V 2n and store the shaping result in the FIFO; P5, perform multi-channel spectral formation on the shaping result.

2. The pseudo-peak correction method based on pulse repair according to claim 1, wherein In the said step P2, obtaining the negative exponential signal specifically includes the following steps: P21 amplifies the negative exponential signal V n and the amplified amplitude range is between 0 - 2V; P22, perform analog-to-digital conversion on the amplified negative exponential signal to obtain a negative exponential pulse sequence V 1n .

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