Neutron pulse signal acquisition and counting device and method

Abstract

The invention relates to the technical field of signal processing of neutron detectors, in particular to a neutron pulse signal collecting and counting device and method. According to the technical scheme, the neutron detector comprises a front signal source, a low-noise signal amplifier, an analog-to-digital conversion module and a signal collecting and processing unit, and the front signal source adopts a microstructure semiconductor neutron detector and is used for receiving neutron radiation and generating charge pulse signals; and the low-noise signal amplifier is connected with the front signal source and is used for amplifying the charge pulse signal. A set of complete neutron signal acquisition and processing system is constructed by integrating a microstructure semiconductor neutron detector, a three-stage low-noise amplification circuit, a high-speed analog-to-digital conversion module based on double-ADC alternate sampling and a self-adaptive digital processing algorithm, so that high sensitivity, low-noise amplification and high-speed sampling are realized, and the detection accuracy is improved. The method has excellent pulse identification precision and real-time energy spectrum reconstruction capability.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology for neutron detectors, and more particularly to a neutron pulse signal acquisition and counting device and method. Background Technology

[0002] Traditional neutron detection technology mainly relies on 3 He gas detectors and scintillator-based detectors (such as lithium glass, ZnS(Ag) / 6 LiF detector. 3 He gas detectors have long been considered the "gold standard" for neutron detection due to their extremely high response cross-section to thermal neutrons, excellent gamma-ray suppression capability, and good energy resolution. However, 3 The increasing scarcity of He gas resources leads to high costs for these detectors. Furthermore, such detectors typically require high-voltage power supplies, resulting in large size, high power consumption, and limited response speed, making them unsuitable for modern demands for miniaturization, low power consumption, and rapid response. While scintillator detectors are relatively cheaper, they also suffer from issues such as large size, susceptibility to ambient light and gamma-ray interference, and the need for complex photoelectric conversion and signal processing systems. Their overall sensitivity and portability still require improvement.

[0003] In recent years, microstructured semiconductor neutron detectors (MSNDs) based on semiconductor processes have attracted widespread attention as an emerging solid-state detection technology. MSNDs typically involve etching micro-holes on a silicon substrate and filling them with enriched electrons. 10 B or 6 The structure of neutron-sensitive materials such as Li involves a nuclear reaction between neutrons and the sensitive material. The resulting secondary charged particles generate electron-hole pairs within the semiconductor, thus forming a measurable charge pulse signal. This differs from traditional methods. 3 Compared with scintillator detectors, MSND has significant advantages such as small size, extremely low power consumption, fast response speed, easy integration and mass production, providing a new technical path for developing a new generation of portable, high-performance neutron monitoring equipment.

[0004] However, while MSNDs offer structural advantages, they also place more stringent demands on their associated signal acquisition and processing systems. First, the raw charge pulse signals output by MSNDs are extremely weak (typically on the order of fC) and have a low signal-to-noise ratio, making them easily overwhelmed by inherent circuit noise. Therefore, a preamplifier circuit with extremely low noise and high gain is required. Second, neutron pulse signals are random and rapid (pulse widths are typically on the order of nanoseconds to microseconds), requiring subsequent signal acquisition systems to have high sampling rates and high time resolution to accurately capture the pulse waveform and avoid signal accumulation or loss. Furthermore, to achieve accurate energy spectrum analysis (such as for neutron dose monitoring or material identification), the system also needs advanced digital signal processing capabilities to stably extract pulse characteristics (such as amplitude and rise time) from the noise background and perform real-time energy spectrum reconstruction.

[0005] Currently, signal processing solutions for MSND (Mean Neutron Pulse Narrowing) often employ discrete components to build an analog front-end, followed by digitization using a general-purpose data acquisition card or microcontroller. These systems often suffer from low integration, unsatisfactory power consumption and size control, and difficulties in balancing real-time performance and accuracy in sampling rates or processing algorithms. In particular, there is a lack of a complete integrated solution specifically tailored to the weak characteristics of MSND signals, encompassing low-noise analog amplification, high-speed digital acquisition, and adaptive digital processing algorithms. Therefore, this application proposes a neutron pulse signal acquisition and counting device and method. Summary of the Invention

[0006] The purpose of this invention is to address the fact that most current signal processing solutions for MSNDs (neutron pulse signals) use discrete components to build an analog front-end, which is then used in conjunction with a general-purpose data acquisition card or microcontroller to achieve digital processing. However, such systems generally suffer from low integration, poor power consumption and size control. Therefore, this invention proposes a neutron pulse signal acquisition and counting device and method.

[0007] In a first aspect, the present invention provides a neutron pulse signal acquisition and counting device, comprising:

[0008] The pre-signal source employs a microstructure semiconductor neutron detector (MSND) to receive neutron radiation and generate charge pulse signals;

[0009] A low-noise signal amplifier, connected to the preamplifier signal source, is used to amplify the charge pulse signal;

[0010] An analog-to-digital converter module, connected to the low-noise signal amplifier, is used to convert the amplified analog signal into a digital signal;

[0011] The signal acquisition and processing unit is connected to the analog-to-digital conversion module and is used to process the digital signal and to identify and count neutron pulse signals.

[0012] The signal acquisition and processing unit includes a dual ADC module based on an STM32H750VBT6 microcontroller. The dual ADC module uses an alternating sampling mode for signal acquisition and supports a sampling rate of up to 7.5 MSPS.

[0013] Optionally, the low-noise signal amplifier is a three-stage low-noise gain amplifier.

[0014] Optionally, the low-noise signal amplifier employs a dual power supply system, including a positive voltage power supply and a negative voltage power supply generated by a charge pump voltage inverter.

[0015] Optionally, the positive voltage is 2-3V.

[0016] Optionally, the signal acquisition and processing unit is also used to execute an adaptive baseline estimation algorithm and a pulse peak extraction algorithm for neutron signal identification and energy spectrum reconstruction.

[0017] Optionally, the signal acquisition and processing unit performs data acquisition and transmission via DMA.

[0018] Optionally, a signal transmission module may also be included for transmitting the processed signal to an external device.

[0019] In a second aspect, the present invention provides a method for acquiring and counting neutron pulse signals, applied to the neutron pulse signal acquisition and counting device described in the first aspect, comprising the following steps:

[0020] Neutron radiation is received and charge pulse signals are generated by a microstructure semiconductor neutron detector (MSND).

[0021] The charge pulse signal is amplified by a low-noise signal amplifier;

[0022] The amplified signal is converted from analog to digital using a dual ADC module in an alternating sampling mode.

[0023] The converted digital signal is processed to identify neutron pulse signals and perform counting.

[0024] Optionally, the processing steps include executing an adaptive baseline estimation algorithm and a pulse peak extraction algorithm.

[0025] Optionally, the pulse peak extraction algorithm includes extracting pulse amplitude and pulse rise edge width feature values ​​for neutron signal identification and energy spectrum reconstruction.

[0026] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0027] By employing a microstructure semiconductor neutron detector (MSND) as the core sensing unit, the device is fundamentally miniaturized, has low power consumption, and high sensitivity, providing a high-quality raw signal source for subsequent processing.

[0028] By using a three-stage low-noise gain amplifier circuit in conjunction with a stable dual-power supply system, the inherent noise of the circuit is effectively suppressed, achieving high-fidelity amplification and transmission of weak charge pulses on the order of femtocoulombs, thus ensuring the signal-to-noise ratio at the front end of the signal chain.

[0029] The dual-ADC alternating sampling architecture based on a high-performance microcontroller increases the system sampling rate to a maximum of 7.5 MSPS, enabling it to capture nanosecond-level fast pulse waveforms and meeting the stringent requirements of neutron signals for high time resolution.

[0030] This invention integrates an adaptive baseline estimation algorithm and a pulse peak extraction algorithm, enabling the system to dynamically adapt to environmental changes, stably and accurately identify valid neutron events from background noise, and extract key features such as amplitude and rise time, thus laying the algorithmic foundation for high-precision energy spectrum reconstruction.

[0031] This invention, through modular hardware design and low-power power management, endows the device with high flexibility, maintainability, and portability, making it suitable for both fixed monitoring stations and handheld mobile devices. Simultaneously, through efficient data transmission and host computer software, it enables real-time data display, remote monitoring, and in-depth analysis.

[0032] In summary, this invention integrates a microstructure semiconductor neutron detector, a three-stage low-noise amplifier circuit, a high-speed analog-to-digital converter module based on dual ADC alternating sampling, and an adaptive digital processing algorithm to construct a complete neutron signal acquisition and processing system. While achieving high sensitivity, low-noise amplification, and high-speed sampling, it also possesses excellent pulse recognition accuracy and real-time energy spectrum reconstruction capabilities. Attached Figure Description

[0033] Figure 1 This is a front view of the MSND detector with added signal amplification base plate structure in this invention;

[0034] Figure 2 This is a schematic diagram of the back side of the MSND detector with added signal amplification base plate structure in this invention;

[0035] Figure 3 This is a flowchart illustrating the working method of a neutron pulse signal acquisition and counting device according to the present invention.

[0036] Figure labels: 1. Microstructured semiconductor neutron detector; 2. Power supply chip; 3. Signal amplifier. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0038] Example 1

[0039] like Figure 1 As shown, this invention proposes a neutron pulse signal acquisition and counting device. Please refer to [link to relevant documentation]. Figure 1 , Figure 2 and Figure 3 The neutron pulse signal acquisition and counting device provided in this embodiment of the invention mainly comprises the following core hardware components: a microstructure semiconductor neutron detector 1 (MSND) as the signal source, a power supply chip 2 that provides stable power to the system, a signal amplifier 3 (i.e., a low-noise signal amplifier) ​​for signal conditioning, a microcontroller (taking STM32H750VBT6 as an example) as the control and processing core, and a host computer platform for external interaction.

[0040] like Figure 3 The flowchart shown illustrates that the operation of the device of the present invention includes the following steps in sequence according to the signal flow direction:

[0041] Step S1: Neutron signal detection and charge generation. When the device is in a neutron radiation field, the microstructured semiconductor neutron detector (MSND) 1 acts as the sensing unit, and its interior is filled with... 10 B or 6 Neutron-sensitive materials such as Li undergo nuclear reactions with incident neutrons (e.g., 10 B(n, α) 7 Li), producing alpha particles and 7 Secondary charged particles, such as Li ions, deposit energy within the semiconductor sensitive volume of the detector, generating a corresponding number of electron-hole pairs, thus forming a weak charge pulse signal related to neutron energy.

[0042] Step S2: Low-noise signal amplification. The original charge pulse signal output by MSND has an extremely small amplitude (typically on the order of femtocoulombs) and a high source impedance. This signal is first fed into a charge-sensitive preamplifier (forming the first stage of a three-stage amplifier circuit). This amplifier uses a high-input-impedance, low-noise operational amplifier design to convert the charge signal into a voltage signal and provide initial gain.

[0043] The signal then enters a secondary amplifier (forming the second and third stages of a tertiary amplifier circuit) for further voltage amplification and shaping. The entire signal amplifier 3 employs a three-stage low-noise gain design and utilizes a dual-power supply system provided by power chip 2 (e.g., a positive voltage of +2.5V, and a negative voltage generated by a charge pump voltage inverter). This design minimizes the circuit's own thermal noise and flicker noise (1 / f noise), ensuring that the signal-to-noise ratio of the weak neutron pulse signal is effectively maintained and improved during amplification.

[0044] Step S3: High-speed analog-to-digital conversion. The fully amplified and shaped analog voltage signal is fed into the dual ADC module integrated within the microcontroller (STM32H750VBT6). This embodiment fully utilizes the characteristics of this module, configuring the two ADCs in an alternating sampling mode. In this mode, when one ADC completes a conversion and enters an idle period, the other ADC immediately starts sampling, thereby increasing the effective sampling rate of the system to twice that of the single ADC mode, supporting a maximum sampling rate of 7.5 MSPS (millions of samples per second). This high-speed sampling capability ensures that neutron pulse waveforms in the nanosecond to microsecond range can be digitized with high fidelity, meeting the requirements for high time resolution acquisition. The preferred bit depth for the analog-to-digital conversion is 16 bits to provide sufficient dynamic range.

[0045] Step S4: Digital signal processing and feature extraction. The digitized signal sequence is processed in real time by the signal acquisition and processing unit within the microcontroller. The core of the processing includes two key algorithms:

[0046] Adaptive baseline estimation algorithm: This algorithm dynamically analyzes the input signal sequence and estimates and tracks the DC baseline voltage of the signal in real time. Even with changes in ambient temperature or slow circuit drift, the algorithm can adaptively adjust the reference to ensure accurate measurement of pulse amplitude.

[0047] Pulse peak extraction algorithm: Based on a stable baseline, the algorithm identifies valid pulse events by setting amplitude and slope (rising edge) thresholds. For each identified pulse, the algorithm accurately calculates its peak amplitude and pulse rising edge width (such as the time required to rise from 10% to 90% of the peak value), among other characteristic parameters.

[0048] Step S5: Data transmission, counting, and energy spectrum reconstruction. The extracted pulse characteristic data (timestamp, amplitude, rise time, etc.) are directly transferred to memory or communication buffer via the microcontroller's DMA (Direct Memory Access) controller, greatly reducing the CPU load and ensuring system real-time performance. The processed data packets are sent to the host computer platform via a signal transmission module (e.g., USB virtual serial port or Ethernet UDP protocol).

[0049] After receiving the data, the host computer software performs the following functions:

[0050] Counting: Accumulate the effective pulses to obtain the neutron count rate.

[0051] Energy spectrum reconstruction: The amplitude of each pulse (related to neutron deposition energy) is filled into the histogram to form the neutron energy spectrum, which is used for radiation field analysis or dose assessment.

[0052] Visualization: Real-time updates and displays count rate curves, energy spectrum, equipment status, etc.

[0053] It should be noted that in other possible embodiments of the present invention: the gain stages of the low-noise amplifier circuit can be adjusted to two or four stages depending on the sensitivity and noise level of the actual detector. The sampling mode of the dual ADCs can also be dynamically switched according to the pulse frequency, using a single ADC mode at low count rates to reduce power consumption. The adaptive baseline estimation algorithm can be implemented using moving average, digital filtering, or more complex statistical methods. The signal transmission module can also be replaced with wireless methods such as Wi-Fi or Bluetooth to adapt to remote or mobile monitoring scenarios.

[0054] The beneficial effects of the technical solutions provided by the embodiments of the present invention are as follows:

[0055] (1) High sensitivity and high precision signal acquisition: A microstructure semiconductor neutron detector (MSND) is used as the signal source, which has excellent thermal neutron response characteristics. The detector is small in size, low in power consumption and fast in response speed, which can effectively improve the sensitivity of signal acquisition and ensure that weak neutron signals can be accurately captured and processed.

[0056] (2) Low-noise signal amplification: The preamplifier adopts a three-stage low-noise gain design, which can effectively amplify weak signals and suppress noise, ensuring signal quality. Combined with a stable dual power supply system, it ensures efficient signal amplification and transmission, maintaining excellent performance in various working environments.

[0057] (3) High-speed and high-precision signal acquisition and conversion: High-speed signal acquisition is achieved by using the dual ADC modules built into the STM32 microcontroller and adopting an alternating sampling mode. The system supports a sampling rate of up to 7.5 MSPS, which meets the high time resolution requirement of neutron pulse signals and effectively ensures the accurate capture of rapidly changing signals.

[0058] (4) Adaptive Algorithm and Precise Signal Processing: By introducing an adaptive baseline estimation algorithm and a pulse peak extraction algorithm, this invention can dynamically adjust the background voltage to adapt to different signal environments, thereby achieving accurate identification and analysis of neutron signals. This algorithm effectively improves the reliability and accuracy of the system in low signal-to-noise ratio environments.

[0059] (5) Modular design and flexible configuration: This system adopts a modular design, which has high flexibility and can be configured and optimized according to actual needs. The modular design makes the system easy to maintain and upgrade, and can adapt to different application scenarios, such as nuclear radiation monitoring, nuclear facility safety inspection, scientific research experiments and other fields.

[0060] (6) Low power consumption and portability: Due to the adoption of a low power consumption design and a 5V battery power supply system, the present invention achieves the portability of the system. The system is suitable for use in portable and handheld devices and can operate stably for a long time in unattended or space-constrained environments.

[0061] (7) Real-time data display and remote monitoring: The host computer platform can intuitively display key parameters such as the energy spectrum and count rate of the neutron signal through a real-time display interface, which is convenient for users to monitor the working status of the equipment in real time. At the same time, the data is transmitted via USB or UDP protocol, supporting remote monitoring and analysis, which enhances the application convenience of the system.

[0062] In summary, this invention effectively solves the bottlenecks of traditional neutron detection equipment in terms of weak signal processing, real-time performance, and portability through collaborative innovation in hardware architecture and software algorithms. This invention uses a microstructured semiconductor neutron detector (MSND) as the signal source, significantly improving the system's sensitivity and integration. Combined with a three-stage low-noise amplifier circuit specifically designed for weak signals and a stable dual-power supply, it ensures high-fidelity amplification and transmission of the front-end signal. Furthermore, by utilizing the dual ADC modules built into the high-performance microcontroller, it achieves high-speed data acquisition of up to 7.5 MSPS in an alternating sampling mode, thereby accurately capturing neutron pulse waveforms in the nanosecond to microsecond range, meeting the requirements for high time resolution measurements.

[0063] Furthermore, this invention introduces adaptive baseline estimation and pulse peak extraction algorithms, enabling dynamic adaptation to environmental changes and accurate identification and analysis of neutron signals from complex noise backgrounds, achieving high-precision energy spectrum reconstruction and counting. The entire device adopts a modular design, facilitating maintenance and functional expansion, and its optimized low-power architecture makes it suitable for battery-powered scenarios, achieving portability and long-term stable operation. Finally, the collected data is received, analyzed, and visualized in real time via a host computer platform.

[0064] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A neutron pulse signal acquisition and counting device, characterized in that, The application relates to a neutron signal acquisition and processing system. The application comprises: a front signal source adopting a microstructure semiconductor neutron detector, which is used for receiving neutron radiation and generating a charge pulse signal; a low-noise signal amplifier connected with the front signal source, which is used for amplifying the charge pulse signal; an analog-digital conversion module connected with the low-noise signal amplifier, which is used for converting the amplified analog signal into a digital signal; a signal acquisition and processing unit connected with the analog-digital conversion module, which is used for processing the digital signal and identifying and counting a neutron pulse signal.

2. A neutron pulse signal acquisition and counting device according to claim 1, characterized in that The signal acquisition and processing unit comprises a double-ADC module based on a microcontroller.

3. A neutron pulse signal acquisition and counting device according to claim 2, wherein, The low-noise signal amplifier is a three-stage low-noise gain amplifier.

4. A neutron pulse signal acquisition and counting device according to claim 3, wherein, The low-noise signal amplifier adopts a double-power supply system, which comprises a positive voltage power supply and a negative voltage power supply generated by a charge pump voltage inverter.

5. The neutron pulse signal acquisition and counting device of claim 1, wherein, The positive voltage is 2-3 V.

6. The neutron pulse signal acquisition and counting device of claim 1, wherein, The signal acquisition and processing unit is also used for executing an adaptive baseline estimation algorithm and a pulse peak extraction algorithm, which are used for identifying a neutron signal and reconstructing an energy spectrum.

7. The neutron pulse signal acquisition and counting device of claim 1, wherein, The signal acquisition and processing unit collects and transmits data in a DMA mode.

8. A method for neutron pulse signal acquisition and counting, applied to the neutron pulse signal acquisition and counting device according to any one of claims 1-7, characterized in that, The application further comprises a signal transmission module, which is used for transmitting the processed signal to an external device. The application comprises the following steps: receiving neutron radiation by a microstructure semiconductor neutron detector and generating a charge pulse signal; amplifying the charge pulse signal by a low-noise signal amplifier; analog-digital converting the amplified signal by a double-ADC module in an alternating sampling mode; 9. The method of claim 8, wherein, processing the converted digital signal, identifying a neutron pulse signal and counting.

10. The method of claim 9, wherein, The processing step comprises executing an adaptive baseline estimation algorithm and a pulse peak extraction algorithm. The pulse peak extraction algorithm comprises extracting a pulse amplitude and a pulse rising edge width characteristic value, which are used for identifying a neutron signal and reconstructing an energy spectrum.

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