Nuclear detection pre-amplification signal self-adaptive preprocessing circuit structure

Abstract

The utility model relates to a nuclear detection pre-amplifier signal self-adaptive preprocessing circuit structure, and solves the technical problems that the switching efficiency is low, the noise before and after switching is inconsistent, the operation error is easy to occur and the intelligence cannot be realized because the existing nuclear detection energy disperse spectroscopy needs to manually set an output signal adaptive to a pre-amplifier. The circuit comprises a driver, a rectifier, a differentiator, a limiter and a baseline shifter connected with an ADC (Analog to Digital Converter), which are sequentially connected along a signal transmission path, the rectifier converts the pre-amplification signal after driving into a positive signal with an unchanged amplitude absolute value, and outputs the positive signal to the differentiator; and the limiter limits the differentiated positive signal and outputs the differentiated positive signal to the baseline shifter. According to the self-adaptive preprocessing circuit structure for the pre-amplification signal of the nuclear detection, the pre-amplification signal is converted into a positive signal with an unchanged amplitude absolute value and limited, and unified preprocessing operation of the positive signal and the negative signal is realized. And a user does not need to care about the positive and negative polarities of the signal and the type of the pre-amplifier, so that the problems existing in manual switching are avoided.

Description

Technical Field

[0001] The utility model relates to a signal adaptation circuit for particle detection, in particular to a nuclear detection preamplifier signal adaptive preprocessing circuit structure, which is used for preprocessing the preamplifier signal input to the ADC in a nuclear detection spectrometer. Background Art

[0002] In the field of particle detection, the signals generated by particle detectors are often very weak and need to be preliminarily amplified and processed by a preamplifier (hereinafter referred to as preamp) to provide a basis for subsequent signal processing and data analysis. The output signals of different types of preamps are also different, with differences in signal polarity, signal type, etc. Some preamps output positive signals, while some output negative signals. For example, the output signal of an RC feedback type charge preamp is a negative exponential decay signal, while the output signal of a reset type charge preamp (also called a transistor recovery type preamp) is a signal pattern of "first rising step by step and resetting when reaching the threshold". This requires the nuclear detection spectrometer located at the backend connected to the preamp to be able to adjust and transform the settings according to the differences in signal polarity or signal type, etc. of different preamps to adapt to the output signals of different preamps (hereinafter referred to as preamp signals).

[0003] The existing transformation setting methods of nuclear detection spectrometers on the market are all in manual mode, which can be specifically divided into a hardware manual setting mode and a software manual setting mode. The hardware manual setting mode is to set switch components such as jumper switches in the hardware system of the nuclear detection spectrometer. Users can switch the jumper switches to adapt to preamp signals of different polarities. The software manual setting mode is to change the switch components in the former to mechanically controlled switches or electronically controlled switches that can be controlled by a program, and then set control options in the spectrometer control software. Users can switch the preamp signals that the nuclear detection spectrometer can adapt to by setting these software control options.

[0004] However, the above two manual setting modes have the following disadvantages:

[0005] (1) Switch components are added to the nuclear detection spectrometer, and each time the switch components are switched, a certain electronic balance time is required, resulting in low switching efficiency.

[0006] (2) The switch components will cause a large amount of noise in the nuclear detection spectrometer at the moment of switching, and there will still be a problem that the noise characteristics are inconsistent with those before switching after stabilization, which requires readjusting the filtering parameters in subsequent signal processing to adapt to the new noise characteristics.

[0007] (3) When using the two manual modes, users may fail to select the signal polarity correctly or forget to select the signal polarity due to operational errors, and then fail to obtain correct test data; sometimes users may suspect that the nuclear detection spectrometer has a malfunction, which seriously affects the user experience. Similarly, since the manual setting mode cannot adapt to the signal, it directly affects the intelligent development of the nuclear detection spectrometer. Utility Model Content

[0008] The purpose of the utility model is to solve the technical problems that the existing nuclear detection spectrometer needs to be manually set to adapt to different polarities or different types of preamplifier output signals, has low switching efficiency, inconsistent noise before and after switching, easy operating errors and cannot be intelligent, and to provide a nuclear detection preamplifier signal adaptive preprocessing circuit structure.

[0009] In order to achieve the above purpose, the technical solutions provided by the utility model are as follows:

[0010] A nuclear detection preamplifier signal adaptive preprocessing circuit structure is used to preprocess the preamplifier signal of ADC in a nuclear detection spectrometer, and its special features are:

[0011] It includes a driver, a rectifier, a differentiator, a stopper and a baseline shifter which are sequentially connected along a signal transmission path; the output end of the baseline shifter is connected to the input end of the ADC;

[0012] The input end of the driver is used to receive the preamplifier signal, and the driver amplifies the power of the preamplifier signal and outputs it to the rectifier;

[0013] The rectifier converts the driven preamplifier signal into a positive signal with constant absolute amplitude and outputs it to the differentiator;

[0014] The differentiator differentiates the obtained positive signal and outputs it to the limiter;

[0015] The limiter adjusts the voltage of the differential positive signal and outputs it to the baseline deflector. The limit range is N to +10V, where N is the negative limit voltage and N<0V.

[0016] The baseline shifter adjusts the baseline of the positive signal after limiting so that it matches the input range of the ADC and outputs it to the ADC, thereby realizing adaptive preprocessing of the preamplifier signal.

[0017] Furthermore, the negative limit voltage N ranges from (-0.2*M)V to (-0.05*M)V, where M is a reference voltage of the ADC.

[0018] Furthermore, the negative limit voltage N=(-0.1*M)V.

[0019] Further, the rectifier includes four unidirectional conduction units. The input ends of the first unidirectional conduction unit and the third unidirectional conduction unit are connected to the input end of the differentiator, and the output ends of the first unidirectional conduction unit and the third unidirectional conduction unit are connected to the output end of the driver. The output end of the first unidirectional conduction unit is connected to the input end of the second unidirectional conduction unit, and the output end of the third unidirectional conduction unit is connected to the input end of the fourth unidirectional conduction unit. The output ends of the second unidirectional conduction unit and the fourth unidirectional conduction unit are connected to the input end of the differentiator.

[0020] Further, the limiter includes a positive clamping circuit and a negative clamping circuit connected in sequence along the signal transmission path;

[0021] The positive clamping circuit is used to limit the positive signal after differentiation below +10V, and the negative clamping circuit limits the positive signal after differentiation above the negative limit voltage N.

[0022] Further, the distortion-free input voltage ranges of the driver, rectifier, differentiator, limiter, and baseline shifter are all -10V to +10V.

[0023] Advantages of the present utility model compared with the prior art:

[0024] 1. For the adaptive preprocessing circuit structure of the nuclear detection preamplifier signal of the present utility model, through the design of the rectifier and the limiter, all preamplifier signals are converted into positive signals with an unchanged absolute value of amplitude and limited within a specified range, realizing the unified preprocessing operation of positive and negative signals. For users, they only need to directly connect the signal line during use without caring about the positive and negative polarities of the signals, which is convenient and intelligent.

[0025] 2. For the adaptive preprocessing circuit structure of the nuclear detection preamplifier signal of the present utility model, a unified preprocessing operation is performed on the preamplifier signal, realizing the unified preprocessing operation of the output signals of different types of preamplifiers, that is, the nuclear detection spectrometer can automatically adapt to signals of different polarities or different types. For users, they only need to directly connect the signal line during use without caring about the types of preamplifiers, which is convenient and intelligent.

[0026] 3. For the adaptive preprocessing circuit structure of the nuclear detection preamplifier signal of the present utility model, there is no need to set a signal polarity selection item, nor do users need to worry about the signal polarity identification problem when running the software. The software development process is more concise and efficient, avoiding the problems existing in manual switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of an embodiment of the adaptive preprocessing circuit structure of the nuclear detection preamplifier signal of the present utility model;

[0028] Figure 2It is a schematic structural diagram of a rectifier in an embodiment of the present utility model;

[0029] Figure 3 It is a schematic structural diagram of a limiter in an embodiment of the present utility model. Specific embodiments

[0030] Next, in combination with the accompanying drawings, the specific technical solutions in the embodiments of the present utility model will be further described. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present utility model.

[0031] The present utility model provides a nuclear detection preamplifier signal adaptive preprocessing circuit structure, aiming to adapt to different types of preamplifier signals and their positive and negative polarities, so as to solve the technical problem that the current spectrometer can only rely on operators to manually select the signal type, thus restricting the intelligent development of the instrument.

[0032] See Figures 1 - 3 , a nuclear detection preamplifier signal adaptive preprocessing circuit structure, used to preprocess the preamplifier signal input to the ADC in a nuclear detection spectrometer, including a driver, a rectifier, a differentiator, a limiter, and a baseline shifter connected in sequence along the signal transmission path; the output end of the baseline shifter is connected to the input end of the ADC; the ADC is connected to a reference voltage.

[0033] The preamplifier signal is driven by the driver and enters the rectifier to complete the rectification conversion of the signal. As a result, all signals are converted into positive signals with an unchanged absolute value of amplitude; then, the signal is differentiated by the differentiator, and then the signal is limited within a specified range by the limiter. Finally, the baseline of the signal is adjusted by the baseline shifter so that the processed signal matches the input range of the ADC and becomes a signal that can be digitized by the ADC, thereby realizing the adaptive preprocessing of the preamplifier signal. Specifically:

[0034] The driver amplifies the power of the preamplifier signal and outputs it to the rectifier.

[0035] The rectifier converts the driven preamplifier signal into a positive signal with an unchanged absolute value of amplitude and outputs it to the differentiator; the rectifier includes four unidirectional conduction units, where the input ends of the first unidirectional conduction unit and the third unidirectional conduction unit are connected to the input end of the differentiator, and the output ends of the first unidirectional conduction unit and the third unidirectional conduction unit are connected to the output end of the driver; the output end of the first unidirectional conduction unit is connected to the input end of the second unidirectional conduction unit, and the output end of the third unidirectional conduction unit is connected to the input end of the fourth unidirectional conduction unit; the output ends of the second unidirectional conduction unit and the fourth unidirectional conduction unit are connected to the input end of the differentiator.

[0036] The differentiator differentiates the obtained positive signal and outputs it to the limiter.

[0037] The limiter adjusts the voltage of the differentiated positive signal and outputs it to the baseline shifter. The limiting range is N to +10V, where N is the negative limiting voltage and N = (-0.1 * M)V, and M is the reference voltage of the ADC. The limiter includes a positive clamping circuit and a negative clamping circuit connected in sequence along the signal transmission path. The positive clamping circuit is used to limit the differentiated positive signal below +10V, and the negative clamping circuit limits the differentiated positive signal above the negative limiting voltage N. The limiter prevents the signal from having excessive negative pulses after passing through the differentiator, which may affect the amplitude value of the subsequent signal.

[0038] The baseline shifter adjusts the baseline of the limited positive signal to match the input range of the ADC and outputs it to the ADC. The baseline of the positive signal is the DC component of the signal, which is used for the negative offset amount to match the ADC input range, enabling the signal to make full use of the effective resolution bits of the ADC during analog-to-digital conversion.

[0039] In the embodiment of the present utility model, the distortion-free input voltage ranges of the driver, rectifier, differentiator, limiter, and baseline shifter are all -10V to +10V.

[0040] The construction method of the embodiment of the present utility model is as follows:

[0041] (0) Prepare the following electronic components: a driver, a rectifier, a differentiator, a limiter, a baseline shifter, a reference voltage, and an ADC;

[0042] (1) Connect the driver, rectifier, differentiator, limiter, baseline shifter, and ADC in sequence according to the order of "the signal enters from the driver and exits from the baseline shifter", and the output of the reference voltage is directly connected to the ADC;

[0043] (2) Set the output voltage limiting range of the limiter to (-0.1 × reference voltage)V to +10V.

[0044] The working principle of the embodiment of the present utility model is as follows:

[0045] The pre-amplified signal enters the rectifier after being driven by the driver to complete signal conversion, and the result is to convert the signal into a positive signal with an unchanged absolute amplitude. Then, it passes through the differentiator to complete signal differentiation and decompose the accumulated signals. After that, the limiter limits the signal within a specified range to prevent serious negative overload of the signal caused by differentiation, which may affect the amplitude value of the subsequent signal. Finally, the baseline shifter adjusts the baseline of the signal to make the processed signal match the input range of the ADC, thus completing the adaptive preprocessing process of the pre-amplified signal.

[0046] The above are only embodiments of the present utility model, and are not limitations on the protection scope of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, is included in the patent protection scope of the present utility model. For those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model, and the scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A nuclear detection preamplifier signal adaptive preprocessing circuit structure, used for preprocessing the preamplifier signal input to ADC in a nuclear detection spectrometer, characterized in that: It includes a driver, a rectifier, a differentiator, a stopper and a baseline shifter which are sequentially connected along a signal transmission path; the output end of the baseline shifter is connected to the input end of the ADC; The input end of the driver is used to receive the preamplifier signal, and the driver amplifies the power of the preamplifier signal and outputs it to the rectifier; The rectifier converts the driven preamplifier signal into a positive signal with a constant absolute amplitude value, and outputs it to the differentiator; The differentiator differentiates the obtained positive signal and outputs it to the limiter; The limiter adjusts the voltage of the differentiated positive signal and outputs it to the baseline deflector, with a limit range of N to +10V, where N is a negative limit voltage and N<0V; The baseline shifter adjusts the baseline of the positive signal after limiting so that it matches the input range of the ADC and outputs it to the ADC, thereby realizing adaptive preprocessing of the preamplifier signal.

2. The nuclear detection preamplifier signal adaptive preprocessing circuit structure according to claim 1 is characterized in that: The negative limit voltage N ranges from (-0.2*M)V to (-0.05*M)V, where M is the reference voltage of ADC.

3. The nuclear detection preamplifier signal adaptive preprocessing circuit structure according to claim 2 is characterized in that: The negative limit voltage N=(-0.1*M)V.

4. The nuclear detection preamplifier signal adaptive preprocessing circuit structure according to any one of claims 1 to 3, characterized in that: The rectifier comprises four unidirectional conductive units, wherein the input ends of the first unidirectional conductive unit and the third unidirectional conductive unit are connected to the input end of the differentiator, and the output ends of the first unidirectional conductive unit and the third unidirectional conductive unit are connected to the output end of the driver; The output end of the first unidirectional conductive unit is connected to the input end of the second unidirectional conductive unit, and the output end of the third unidirectional conductive unit is connected to the input end of the fourth unidirectional conductive unit; The output ends of the second unidirectional conductive unit and the fourth unidirectional conductive unit are connected to the input end of the differentiator.

5. The nuclear detection preamplifier signal adaptive preprocessing circuit structure according to claim 4 is characterized in that: The limiter comprises a positive clamping circuit and a negative clamping circuit connected in sequence along the signal transmission path; The positive clamp circuit is used to limit the positive signal after differentiation to below +10V, and the negative clamp circuit is used to limit the positive signal after differentiation to above the negative limit voltage N.

6. The nuclear detection preamplifier signal adaptive preprocessing circuit structure according to claim 5 is characterized in that: The undistorted input voltage range of the driver, rectifier, differentiator, stopper and baseline deflector is -10V to +10V.

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