Multiplication acquisition device for weak analog signal of low-energy ion detector

Abstract

The invention belongs to the technical field of low-energy ion detection, and relates to a multiplication acquisition device for weak analog signals of a low-energy ion detector, which is used for carrying out square or cubic operation on current signals acquired by the low-energy ion detector and comprises a current-voltage conversion circuit, an analog-to-digital conversion circuit and an analog-to-digital conversion circuit which are sequentially connected in series, the current-voltage conversion circuit is used for converting a micro current signal acquired by the low-energy ion detector into a voltage signal; the subtraction proportion operation circuit is used for subtracting the scanning reference voltage applied to the ion detector; the square root operation circuit is used for carrying out nonlinear conversion according to the intensity of an output analog signal of the subtraction proportion operation circuit and enhancing a weak signal with a high gain and enhancing a strong signal with a relatively low gain so as to realize a square root function, and the cubic root operation circuit is used for carrying out nonlinear conversion according to the intensity of an output signal of the subtraction proportion operation circuit and enhancing a strong signal with a relatively low gain so as to realize a square root function. And the cube opening function is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of low-energy ion detection, and in particular relates to a multiplication acquisition device for weak analog signals of a low-energy ion detector. Background Art

[0002] In today's low-energy particle physics research and applications, accurate detection of low-energy ions plays a vital role. Especially in the fields of plasma physics, astrophysics, and space physics, low-energy ion detectors are widely used to obtain particle parameters and study plasma environment characteristics. However, the signal intensity of low-energy ions is usually weak, especially in a vacuum environment or space plasma. The magnitude of the current signal is often in the microampere or even picoampere level, and it usually shows a variation range of more than 40dB in the same acquisition. The stable and accurate acquisition of such weak signals is one of the key challenges to ensure the performance of the detector.

[0003] The difficulties in collecting weak current signals are mainly reflected in the low intensity of the signal, the fast change speed, and the susceptibility to external interference, which requires the acquisition device to have extremely high sensitivity and signal-to-noise ratio. In addition, the stable acquisition of microcurrent signals requires not only a high-precision amplification device, but also a large dynamic range to cope with complex and changeable experimental environments and application requirements. When facing extremely low currents, traditional signal acquisition systems often have problems such as excessive noise, insufficient sensitivity, and limited dynamic range, resulting in data acquisition accuracy and reliability that cannot meet the requirements of high-precision detection. With the development of science and technology, analog multiplier technology has been widely used in the field of microcurrent signal enhancement and processing due to its high gain and low noise characteristics. This provides an effective solution for the acquisition of microcurrent signals in low-energy ion detectors.

[0004] Therefore, there is an urgent need to develop a micro-current acquisition device combined with an analog multiplier and related methods, which can not only greatly improve the sensitivity of the low-energy ion detector, but also expand its dynamic range and achieve stable and high-precision acquisition of weak current signals. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and propose a multiplication acquisition device for weak analog signals of low-energy ion detectors.

[0006] In order to achieve the above-mentioned object, the present invention proposes a multiplication acquisition device for weak analog signals of low-energy ion detectors, which is used to perform square root operation on the current signal collected by the low-energy ion detector. The device comprises: a current-voltage conversion circuit, a subtraction proportional operation circuit and a square root operation circuit connected in series in sequence, wherein:

[0007] The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal;

[0008] The subtraction proportional operation circuit is used to subtract the scanning reference voltage applied to the ion detector;

[0009] The square root operation circuit is used to perform nonlinear conversion according to the output analog signal strength of the subtraction proportional operation circuit, enhance weak signals with high gain and enhance strong signals with lower gain, so as to realize the square root function.

[0010] Preferably, the current-to-voltage conversion circuit includes an operational amplifier and a jumper resistor, the reverse input end of the operational amplifier is connected to the low-energy ion detector and the jumper resistor, the tiny signal collected by the ion detector is converted into a voltage signal through the jumper resistor, and the positive input end is connected to the reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback capacitor is connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

[0011] Preferably, the subtraction proportional operation circuit includes an operational amplifier, the reverse input terminal of the operational amplifier is connected to the output terminal of the current-voltage conversion circuit through a series resistor, and the forward input terminal is divided into two paths, one path is connected to the ground after passing through the series resistor, and the other path is connected to the reference voltage V after passing through the series resistor. REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

[0012] Preferably, the square root operation circuit includes an operational amplifier and an analog multiplier, wherein:

[0013] The reverse input terminal of the operational amplifier is divided into two paths, one of which is connected to the output terminal of the subtraction proportional operation circuit through a series resistor, and the other is connected to the output terminal of the analog multiplier through a series resistor. The forward input terminal of the operational amplifier is grounded after passing through a series resistor, and the output terminal of the operational amplifier is connected to the two input terminals of the analog multiplier after passing through a parallel diode and a capacitor.

[0014] On the other hand, the present invention also proposes a multiplication acquisition device for weak analog signals of low-energy ion detectors, which is used to perform cube root operation on the current signal collected by the low-energy ion detector. The device comprises: a current-voltage conversion circuit, a subtraction proportional operation circuit and a cube root operation circuit connected in series in sequence, wherein:

[0015] The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal;

[0016] The subtraction proportional operation circuit is used to subtract the scanning reference voltage applied to the ion detector;

[0017] The cube root operation circuit is used to perform nonlinear conversion according to the output signal strength of the subtraction proportional operation circuit to realize the cube root function.

[0018] Preferably, the current-voltage conversion circuit includes an operational amplifier, the reverse input terminal of the operational amplifier is connected to the low-energy ion detector for inputting a small current signal, and the forward input terminal is connected to the reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback resistor and capacitor are connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

[0019] Preferably, the subtraction proportional operation circuit includes an operational amplifier, the reverse input terminal of the operational amplifier is connected to the output terminal of the current-voltage conversion circuit through a series resistor, and the forward input terminal is divided into two paths, one path is connected to the ground after passing through the series resistor, and the other path is connected to the reference voltage V after passing through the series resistor. REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

[0020] Preferably, the cube root operation circuit includes an operational amplifier and an analog multiplier, wherein:

[0021] The reverse input end of the operational amplifier is divided into two paths, one of which is connected to the output end of the subtraction proportional operation circuit through a series resistor, and the other is connected to the output end of the first analog multiplier through a series resistor. The positive input end of the operational amplifier is grounded after passing through a series resistor. The output end of the operational amplifier is connected to the two input ends of the second analog multiplier and one input end of the first analog multiplier through a parallel diode and a capacitor. The other input end of the first analog multiplier is connected to the output end of the second analog multiplier.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] The present invention proposes an analog multiplication acquisition device suitable for weak signals of low-energy ion detectors, which can achieve high-precision enhancement and stable acquisition of tiny current signals. By introducing an analog multiplier, the dynamic range of signal acquisition is effectively expanded, and the signal is enhanced and processed to ensure the stability and accuracy of signal acquisition quality, thereby meeting the needs of high-precision measurement of weak signals and improving the reliability and anti-interference ability of the system.

[0024] It is widely used in the fields of plasma physics, space exploration, materials science, etc. It will greatly improve the measurement accuracy and data reliability of low-energy ion detectors in complex environments, and provide important support for technological progress in related fields such as plasma physics research and space low-energy ion detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a general analog multiplier circuit;

[0026] Figure 2 It is a series circuit of two analog multipliers;

[0027] Figure 3 This is the schematic diagram of the square root operation circuit;

[0028] Figure 4 It is the overall square root signal processing circuit diagram;

[0029] Figure 5 It is the circuit diagram of cube root operation;

[0030] Figure 6 It is the overall cubic root signal processing circuit diagram;

[0031] Figure 7 This is the simulation diagram of the overall square root signal processing circuit;

[0032] Figure 8 This is the simulation diagram of the overall cubic root signal processing circuit;

[0033] Fig. 9 This is a comparison chart of signals collected by linear, square root and cube root circuits. DETAILED DESCRIPTION

[0034] The present invention relates to an analog multiplication acquisition device suitable for weak signals of low-energy ion detectors, and in particular, combined with an analog multiplier, square root or cube root operation can be realized in analog signal processing, so that stable and high-precision acquisition of weak signals can be achieved, and a large dynamic range can be achieved. This device is used in a low-energy particle detection environment to accurately measure the weak current signal generated by the detector, and enhance and process the signal to ensure the stability and accuracy of the signal acquisition quality.

[0035] 1 Principle design

[0036] In order to achieve accurate acquisition and amplification and enhancement of current signals with a large dynamic range, it is difficult for general linear amplifier circuits to complete the task. Taking into account the characteristics of various signal processing circuits and the characteristics of low-energy ion parameters, a weak signal acquisition system combined with analog multipliers has been developed. In view of the two characteristics of low-energy ion detectors, that the current collected is very weak and the dynamic range varies with the low-energy ion density, an amplifier circuit based on square or cubic operations combined with analog multipliers is designed to perform pre-processing before analog-to-digital conversion of the current. Its core is the combination operation of analog multipliers. General analog multipliers such as Figure 1 shown.

[0037] Different from the volt-ampere characteristic of resistors, the voltage output at both ends of the analog multiplier changes with the input. The square or cube operation has the effect of significantly compressing the dynamic range and is sensitive to small current changes. Therefore, the use of square or cube amplification circuits is conducive to compressing the dynamic range of the collected current and improving the sensitivity of the system to small current collection. The relationship between the output and input of the analog multiplier is shown in formula (1).

[0038] U o =kU x U y (1)

[0039] Where U o is the output voltage of the analog multiplier, U x , U y is the input voltage of the analog multiplier, k is a constant. x =U y When , the above formula can be changed into:

[0040]

[0041] When two analog multipliers are Figure 2 When connected in series, the relationship between the output and input is:

[0042]

[0043] As shown in formula (2) and formula (3), there is a square or cube relationship between the output and input of the analog multiplier. Therefore, the analog multiplier can be used to form a square or cube operation circuit.

[0044] 1) Square root signal processing circuit

[0045] like Figure 3As shown, the analog multiplier is the core of the square root operation circuit, which can multiply two input signals and output the product signal. In the square root operation circuit, the characteristics of the multiplier are used to construct the square relationship between the output signal and the input signal. The operational amplifier is used as a feedback and control element in the square root circuit to ensure that the circuit can work stably. The purpose of connecting a diode in series and a capacitor in parallel at the output end of the operational amplifier is to prevent the occurrence of latch-up phenomenon and reduce noise and interference in the signal, which plays a role in signal smoothing. The operational amplifier adjusts the signal in the circuit through the feedback mechanism to ensure that the output signal and the input signal meet the square relationship. The operational amplifier using negative feedback is combined with the analog multiplier to form a closed-loop system to realize the square root function. Specifically, the square root circuit ensures that the output signal satisfies the following through feedback adjustment:

[0046]

[0047] Among them, u i is the input signal, which must satisfy u i >0.u o is the output signal. k is a constant.

[0048] The complete square root signal processing circuit is as follows Figure 4 The specific circuit structure is divided into the following three parts: current-voltage conversion circuit, subtraction proportional operation circuit and square root operation circuit.

[0049] The main function of the current-voltage conversion circuit is to convert the tiny current signal collected by the low-energy ion detector into a voltage signal. The reverse input terminal of the operational amplifier is connected to the low-energy ion detector for the input of the micro-current signal. The positive input terminal is connected to the reference voltage V REF The circuit is connected to ensure that it works in a stable state and can collect the tiny current on the low-energy ion detector. The feedback resistor and capacitor ensure the stability and linearity of the output signal, and the resistor is connected to the subsequent subtraction proportional operation circuit to further process the signal.

[0050] The function of the subtraction proportional operation circuit is to convert the scanning reference voltage V applied to the ion detector into REF Subtract; make the final current signal more accurate. The operational amplifier stabilizes the output through feedback resistors and capacitors, and compares it with the reference voltage V REF connections for precise signal processing.

[0051] The square root operation circuit is used to perform nonlinear conversion on the output signal of the subtraction proportional operation circuit. Due to the characteristics of the square root operation, the positive and negative values ​​of the input voltage need to be controlled to ensure that ku iis a positive value. Otherwise, the circuit will not work properly. The square root operation circuit performs nonlinear amplification according to the signal strength. When the signal is small, the amplification factor is large, thereby improving the signal-to-noise ratio of the small signal; when the signal is large, the amplification factor is reduced, ensuring that the signal acquisition end has a large dynamic range.

[0052] The output of the circuit is connected to a filter circuit and an analog-to-digital conversion circuit for subsequent processing.

[0053] 2) Cube root signal processing circuit

[0054] like Figure 5 As shown in the figure, the negative feedback branch of the operational amplifier of the cube root operation circuit uses two analog multipliers in series to ensure that the output signal satisfies:

[0055]

[0056] Among them, u i is the input signal, u o is the output signal, k is a constant.

[0057] The complete cube root signal processing circuit is as follows Figure 6 The specific circuit structure is also divided into the following three parts: current-voltage conversion circuit, subtraction proportional operation circuit and cube root operation circuit.

[0058] Due to the characteristics of the cube root operation, this circuit does not need to control the positive and negative values ​​of the input voltage, and has a larger dynamic range. Compared with the square root operation circuit, the cube root signal processing circuit has fewer restrictions, a wider range of applications, and more applicable conditions.

[0059] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0060] Example 1

[0061] In order to verify the actual effect of the square root and cube root operation circuit in the present invention, we used simulation software to build and simulate the circuit. The purpose of the experiment is to verify the effectiveness of the circuit design of the present invention through the processing of analog signals, especially the high-precision amplification and stable acquisition capabilities of micro-current signals. The following is the specific experimental verification process and result analysis.

[0062] like Figure 7 As shown, according to the invention principle, a square root operation circuit based on an analog multiplier and an operational amplifier is built in the simulation software. Specifically, it includes: a current-voltage conversion circuit, a subtraction ratio operation circuit and a square root operation circuit connected in series in sequence, wherein:

[0063] The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal; it includes an operational amplifier and a jumper resistor, the reverse input end of the operational amplifier is connected to the low-energy ion detector and the jumper resistor, the tiny signal collected by the ion detector is converted into a voltage signal through the jumper resistor, and the positive input end is connected to the reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback capacitor is connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

[0064] The subtraction proportional operation circuit is used to subtract the scanning reference voltage applied to the ion detector; it includes an operational amplifier, the reverse input end of the operational amplifier is connected to the output end of the current-voltage conversion circuit through a series resistor, and the positive input end is divided into two paths, one is connected to the ground after passing through the series resistor, and the other is connected to the reference voltage V after passing through the series resistor. REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

[0065] The square root operation circuit is used to perform nonlinear conversion according to the output analog signal strength of the subtraction proportional operation circuit, enhance weak signals with high gain, and enhance strong signals with lower gain, so as to realize the square root function. It includes an operational amplifier and an analog multiplier, wherein:

[0066] The reverse input terminal of the operational amplifier is divided into two paths, one of which is connected to the output terminal of the subtraction proportional operation circuit through a series resistor, and the other is connected to the output terminal of the analog multiplier through a series resistor. The positive input terminal of the operational amplifier is grounded after passing through a series resistor, and the output terminal of the operational amplifier is connected to the two input terminals of the analog multiplier after passing through a parallel diode and a capacitor.

[0067] The circuit inputs a small current signal, passes through the current-voltage conversion circuit, the subtraction proportional operation circuit, and finally performs nonlinear amplification processing by the square root operation circuit. Through the negative feedback mechanism, it ensures that the output voltage signal and the input current signal meet the square relationship.

[0068] The experimental results show that the output signal of the square root signal processing circuit is in good agreement with the square of the input signal. For input signals of different amplitudes, the output voltage can stably and accurately reflect the signal changes, and exhibits a high signal-to-noise ratio under small signal conditions. The experiment verifies the effectiveness of the circuit in micro-current signal processing, especially in dynamic range expansion and signal amplification.

[0069] Example 2

[0070] like Figure 8As shown, the simulation software is also used to build a cube root signal processing circuit. The operational amplifier realizes the cube root operation through two analog multipliers connected in series. It includes: a current-voltage conversion circuit, a subtraction ratio operation circuit and a cube root operation circuit connected in series in sequence, wherein:

[0071] The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal; it includes an operational amplifier, the reverse input end of the operational amplifier is connected to the low-energy ion detector for inputting the tiny current signal, and the positive input end is connected to the reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback resistor and capacitor are connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

[0072] The subtraction proportional operation circuit is used to convert the scanning reference voltage V applied to the ion detector REF Subtract; including an operational amplifier, the inverting input terminal of the operational amplifier is connected to the output terminal of the current-voltage conversion circuit through a series resistor, and the positive input terminal is divided into two paths, one path is connected to the ground through a series resistor, and the other path is connected to the reference voltage V through a series resistor REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

[0073] The cube root operation circuit is used for performing nonlinear conversion according to the output signal strength of the subtraction ratio operation circuit to realize the cube root function. It includes an operational amplifier and an analog multiplier, wherein the reverse input end of the operational amplifier is divided into two paths, one path is connected to the output end of the subtraction ratio operation circuit through a series resistor, and the other path is connected to the output end of the first analog multiplier through a series resistor, the positive input end of the operational amplifier is grounded after passing through the series resistor, the output end of the operational amplifier is connected to both input ends of the second analog multiplier and one input end of the first analog multiplier through a parallel diode and a capacitor, and the other input end of the first analog multiplier is connected to the output end of the second analog multiplier.

[0074] The circuit does not need to control the positive and negative values ​​of the input signal, and realizes cubic operational amplification of tiny current signals through the circuit structure. This design is used to verify the processing capability of signals with a larger range of variation.

[0075] The cube root signal processing circuit also achieved the expected effect, and the cubic relationship between the output signal and the input current was in line with theoretical expectations. The simulation results showed that the circuit performed well under a larger dynamic range, adapted to signal inputs of different intensities, and maintained high accuracy and stability under high input signal conditions.

[0076] In addition, in order to verify the effectiveness and performance of the present invention, we also used the AD633 analog multiplier and the OPA2196 operational amplifier to build an overall square root and cube root signal processing circuit according to the design scheme, and ensured the correctness of the circuit connection and the stability of the components. The circuit has been repeatedly adjusted and calibrated to ensure the stable operation of the operational circuit, and a standard current source is used as the input signal to set different current values. The input range covers from picoamperes to microamperes to simulate weak current signals in a low-energy ion detection environment. The output voltage of the circuit is measured by a high-precision multimeter to record the output voltage values ​​under different input current conditions, and ensure that the measurement environment is stable to avoid the influence of external noise and temperature changes on the measurement results. According to the relationship between the output voltage and the input current, the model of the overall square root and cube root signal processing circuit is used to perform data calculations to verify whether the output voltage meets theoretical expectations. The experimental results are as follows Fig. 9 By analyzing the experimental data under different current input conditions, the experimental results verify that the relationship between the output voltage and input current of the circuit meets the theoretical expectations of the overall square root and cube root signal processing circuit, and verify the effectiveness of the circuit design. The experimental results also show that the device has high accuracy in the acquisition and processing of tiny current signals, and the dynamic range of the acquisition meets expectations.

[0077] Conclusion

[0078] The present invention proposes a weak signal acquisition device and method combined with an analog multiplier suitable for low-energy ion detectors, which successfully solves the technical problem that weak signals in low-energy particle detection are difficult to acquire stably and accurately. By introducing an analog multiplier to realize the square or cubic operation of the analog signal, the device not only improves the amplification accuracy of the microcurrent signal, but also effectively expands the dynamic range of acquisition, enhances the system's anti-interference ability and the stability of data acquisition. Experimental results show that the present invention has broad application prospects in multiple fields such as plasma physics, space low-energy ion detection, and material science, and will provide reliable technical support for related technical research and industrial applications. In short, the present invention has opened up a new solution path for the microcurrent acquisition technology of low-energy ion detectors, which has important practical application value and theoretical significance.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A multiplication acquisition device for weak analog signals of low-energy ion detectors, used for performing square root operation on current signals collected by low-energy ion detectors, characterized in that: The device comprises: a current-voltage conversion circuit, a subtraction proportional operation circuit and a square root operation circuit connected in series in sequence, wherein: The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal; The subtraction proportional operation circuit is used to subtract the scanning reference voltage applied to the ion detector; The square root operation circuit is used to perform nonlinear conversion according to the output analog signal strength of the subtraction proportional operation circuit, enhance weak signals with high gain and enhance strong signals with lower gain, so as to realize the square root function.

2. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 1, characterized in that: The current-voltage conversion circuit includes an operational amplifier and a jumper resistor. The reverse input end of the operational amplifier is connected to the low-energy ion detector and the jumper resistor. The tiny signal collected by the ion detector is converted into a voltage signal through the jumper resistor. The positive input end is connected to the reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback capacitor is connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

3. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 2, characterized in that: The subtraction proportional operation circuit includes an operational amplifier, the reverse input end of the operational amplifier is connected to the output end of the current-voltage conversion circuit through a series resistor, and the forward input end is divided into two paths, one path is connected to the ground after passing through the series resistor, and the other path is connected to the reference voltage V after passing through the series resistor. REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

4. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 3, characterized in that: The square root operation circuit includes an operational amplifier and an analog multiplier, wherein: The reverse input terminal of the operational amplifier is divided into two paths, one of which is connected to the output terminal of the subtraction proportional operation circuit through a series resistor, and the other is connected to the output terminal of the analog multiplier through a series resistor. The forward input terminal of the operational amplifier is grounded after passing through a series resistor, and the output terminal of the operational amplifier is connected to the two input terminals of the analog multiplier after passing through a parallel diode and a capacitor.

5. A multiplication acquisition device for weak analog signals of low-energy ion detectors, used for performing cube root operation on current signals collected by low-energy ion detectors, characterized in that: The device comprises: a current-voltage conversion circuit, a subtraction ratio operation circuit and a cube root operation circuit connected in series in sequence, wherein: The current-voltage conversion circuit is used to convert the tiny current signal collected by the low-energy ion detector into a voltage signal; The subtraction proportional operation circuit is used to subtract the scanning reference voltage applied to the ion detector; The cube root operation circuit is used to perform nonlinear conversion according to the output signal strength of the subtraction proportional operation circuit to realize the cube root function.

6. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 5, characterized in that: The current-voltage conversion circuit includes an operational amplifier, the reverse input terminal of the operational amplifier is connected to the low-energy ion detector for inputting a small current signal, and the forward input terminal is connected to a reference voltage V REF The operational amplifier is connected to ensure that the circuit works in a stable state; the feedback resistor and capacitor are connected in parallel between the reverse input terminal and the output terminal of the operational amplifier to ensure the stability and linearity of the output signal at the output terminal of the operational amplifier.

7. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 6, characterized in that: The subtraction proportional operation circuit includes an operational amplifier, the reverse input end of the operational amplifier is connected to the output end of the current-voltage conversion circuit through a series resistor, and the forward input end is divided into two paths, one path is connected to the ground after passing through the series resistor, and the other path is connected to the reference voltage V after passing through the series resistor. REF Connected, a feedback resistor and capacitor are connected in parallel between the inverting input and output of the operational amplifier.

8. The multiplication acquisition device for weak analog signals of low-energy ion detectors according to claim 7, characterized in that: The cube root operation circuit includes an operational amplifier and an analog multiplier, wherein: The reverse input end of the operational amplifier is divided into two paths, one of which is connected to the output end of the subtraction proportional operation circuit through a series resistor, and the other is connected to the output end of the first analog multiplier through a series resistor. The positive input end of the operational amplifier is grounded after passing through a series resistor. The output end of the operational amplifier is connected to the two input ends of the second analog multiplier and one input end of the first analog multiplier through a parallel diode and a capacitor. The other input end of the first analog multiplier is connected to the output end of the second analog multiplier.

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