Single-ball neutron spectrometer electronic system

Abstract

The invention discloses a single-ball neutron spectrometer electronic system, and compared with the prior art, the single-ball neutron spectrometer electronic system is provided with a plurality of independent signal processing channels respectively corresponding to a detector 1, a detector 2,..., and a detector n; the method comprises the following steps: converting and amplifying each path of signal through a charge sensitive preamplifier, correcting the waveform through a polar zero cancellation circuit, outputting a standard pulse through a pulse conditioning module, and respectively sending the standard pulse into a counting module channel 1, a counting module channel 2,..., a counting module channel n in an FPGA (Field Programmable Gate Array) for parallel counting, a counting result is written into an n-channel data RAM (Random Access Memory) cache, is stably operated under the guarantee of clock and Flash configuration, and is finally transmitted to an upper computer through an Ethernet module according to TCP / IP (Transmission Control Protocol / Internet Protocol); and meanwhile, the low-ripple power supply module supplies power to each link so as to reduce noise interference, so that the integrity and stability of counting data acquisition of the multiple detectors are ensured from the structure and the data flow path.

Description

Technical Field

[0001] This invention relates to the field of neutron energy spectrum measurement, and more specifically to an electronic system for a single-sphere neutron spectrometer. Background Technology

[0002] Neutrons are widely present in scenarios such as nuclear power, medical radiation protection, accelerator devices, and nuclear facility monitoring. Due to the complex interaction mechanism between neutrons and matter, and the close relationship between neutron dosimetry and neutron energy, accurately obtaining the neutron energy spectrum is a crucial foundation for neutron dose measurement and risk assessment in radiation protection and dose assessment. Existing in-situ neutron dose measurement devices are represented by moderated Rem meters and multi-sphere neutron spectrometers. Moderated Rem meters typically consist of a thermal neutron detector encased in moderting material. While their structure is relatively simple, their energy response is difficult to further improve in design, easily leading to insufficient accuracy in dose results. Multi-sphere neutron spectrometers, on the other hand, inversely solve the energy spectrum by using the different responses of moder spheres of different radii to neutrons of different energies, resulting in relatively better accuracy in energy spectrum measurement. However, significant bottlenecks remain in their application and implementation in engineering.

[0003] Specifically, multi-sphere neutron spectrometers consist of multiple moderator spheres, resulting in a large overall size and inconvenient portability and deployment. Measurements typically require placing multiple neutron spheres one by one at the measurement point to sequentially collect counting data before energy spectrum results can be obtained in subsequent calculations, leading to cumbersome measurement procedures and long measurement cycles. More importantly, the time-sharing measurement method involving multiple moderator sphere replacements makes it difficult to ensure the neutron field remains stable throughout the measurement process. In cases of neutron field fluctuations, non-simultaneous measurements introduce non-negligible systematic errors, affecting the reliability of energy spectrum inversion results. To simplify the operation, single-sphere neutron spectrometer configurations, embedding multiple thermal neutron detectors within a single moderator body, have emerged in recent years. These configurations obtain counting information from multiple detectors simultaneously in a single measurement to support energy spectrum inversion, reducing the need for moderator sphere replacements and improving measurement efficiency. However, the key to the engineering implementation of such single-sphere multi-detector spectrometers lies in whether the electronic system can achieve stable, synchronous, and parallel pulse processing and counting of the output signals from multiple detectors; otherwise, it remains difficult to meet the online measurement goal of "acquiring full data in a single measurement."

[0004] In terms of the electronic implementation of single-sphere multi-detector spectrometers, there are still several unresolved issues in the existing technology.

[0005] First, the electrical signals output by thermal neutron detectors are often extremely weak, belonging to the low charge / low current level, with current amplitude on the order of pA, making them susceptible to noise interference. If there is a lack of low-noise front-end conversion and amplification capabilities for weak charge pulses, it will lead to insufficient effective pulse amplitude and a decrease in signal-to-noise ratio, resulting in unstable counting, increased lost counts, and more false counts.

[0006] Secondly, in scenarios with high neutron flux, the nuclear pulses amplified at the front end are prone to pulse accumulation and baseline rise. Pulse waveform distortion makes it difficult for subsequent discrimination and counting circuits to accurately extract the effective rising edge, resulting in count loss or false triggering. Without a correction mechanism for pulse distortion and undershoot and an effective means of pulse width compression, the throughput and accuracy of the system under high count rate conditions cannot be guaranteed.

[0007] Furthermore, single-sphere neutron spectrometers often need to process multiple signals from multiple detectors simultaneously. If the electronic system still uses channel multiplexing, time-division scanning, or lacks an independent processing structure between channels, it is easy to cause problems such as inconsistent timing between channels, data asynchrony, and insufficient multi-channel data throughput. Ultimately, this will prevent the true realization of "synchronous acquisition of multi-detector counting data within the same measurement time window", thereby weakening the online measurement advantages that single-sphere spectrometers should have.

[0008] Finally, stable power supply and data transmission of the electronic system are also key factors affecting the reliability of online measurement: power supply ripple and noise will be directly superimposed on weak pulse signals, reducing counting reliability; and without a stable clock and configuration management mechanism, multi-channel data buffer and high-speed communication link, it is difficult to achieve orderly temporary storage, real-time uploading and online processing of multi-channel counting data by the host computer.

[0009] In summary, existing neutron energy spectrum measurement techniques still have the following prominent shortcomings in engineering applications: First, it is difficult to stably, synchronously, and in parallel acquire and reliably upload the counting data of multiple detectors in a single measurement, which makes it difficult to fully realize the online measurement advantages of a single-sphere multi-detector spectrometer. Secondly, under high count rate conditions, the counting inaccuracies caused by pulse accumulation, undershoot, and waveform distortion have not been effectively suppressed. Third, the lack of a system-level collaborative design for low-noise power supply, data buffering, and high-speed communication for multi-channel online measurement results in insufficient real-time performance and stability. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a single-sphere neutron spectrometer electronic system that enables synchronous parallel processing and reliable counting of weak pulse signals output by detectors 1, 2 to n with a high count rate.

[0011] To solve the above-mentioned technical problems, the technical method adopted by the present invention is as follows: The present invention discloses a single-sphere neutron spectrometer electronic system, including a detection system, an electronics system and a spectrum interpretation system, characterized in that: the detection system includes a single moderator and multiple thermal neutron detectors embedded in different positions within the moderator, used to convert the neutron radiation of the measured neutron field into a pulse signal recognizable by the electronics system; The electronic system includes multiple front-end signal conversion circuits, multiple pulse conditioning circuits, an FPGA module, a communication interface module, and a low-ripple power supply module. The front-end signal conversion circuit, each corresponding to one of the thermal neutron detectors, includes a charge-sensitive preamplifier and a pole-zero cancellation circuit, used to convert the weak charge signal output by the thermal neutron detector into a voltage signal and perform preliminary amplification, while compensating for and correcting the distortion generated during the detector and preamplification process. The pulse conditioning circuit is connected to the output of the front-end signal conversion circuit and is used to perform waveform shaping and filtering on the calibrated pulse signal to condition the pulse signal into a standard pulse that meets the subsequent counting requirements. Each detector signal corresponds to an independent pulse conditioning circuit to ensure independent parallel processing of multi-channel signals. The FPGA module is connected to the output of all the pulse conditioning circuits and is used to perform parallel counting and data processing of multi-channel pulse signals. The FPGA module integrates multiple pulse counting modules corresponding to each channel, a data storage device for temporarily storing multi-channel counting data, and an energy spectrum acquisition module for acquiring pulse energy spectrum information. It is also equipped with a clock and configuration storage unit, thereby realizing the acquisition and temporary storage of pulse count values ​​of each channel, as well as the synchronous acquisition of pulse energy spectrum data, and ensuring that each functional module of the FPGA operates according to a predetermined logical timing. The communication interface module is connected to the FPGA module, converts the counting data and energy spectrum data processed by the FPGA module into network signals, and transmits them to the host computer via TCP / IP protocol to achieve high-speed remote data transmission and interaction. The low-ripple power supply module provides a stable, low-noise DC power supply to each module of the electronic system, avoiding interference from power supply ripple on signal processing. The spectrum interpretation system is spectrum interpretation software running on a host computer, used to calculate the neutron energy spectrum based on the multi-channel counting data.

[0012] Furthermore, all of the thermal neutron detectors are coated. 6 SiC semiconductor thermal neutron detectors made of LiF material.

[0013] Furthermore, the output signal of each thermal neutron detector is processed sequentially by a corresponding charge-sensitive preamplifier and a pole-zero cancellation circuit. The charge-sensitive preamplifier converts the weak output charge signal into a voltage signal and amplifies it. The pole-zero cancellation circuit compensates for the undershoot distortion generated by the previous stage and shortens the pulse width to reduce the impact of pulse accumulation at high count rates.

[0014] Furthermore, the pulse conditioning circuit performs waveform shaping and filtering on the pulse signal after correction by the pole-zero cancellation circuit, adjusting the amplitude and width of the pulse to a predetermined range to output a standard pulse signal that meets the counting requirements, and ensuring independent parallel processing of signals from each channel.

[0015] Furthermore, the multiple pulse counting modules set within the FPGA module count the pulse signals of each channel and count the number of pulses per unit time to obtain the pulse counting rate of the corresponding channel.

[0016] Furthermore, the data storage is used to temporarily store the counting data output by the multiple pulse counting modules, serving as a data cache unit to coordinate the data transmission and processing rhythm within the system, thereby ensuring the orderly flow of multi-channel counting data within the system and providing temporary storage space for subsequent data transmission or further processing.

[0017] Furthermore, the energy spectrum acquisition module works in parallel with the multiple pulse counting modules to acquire and process energy spectrum-related information of the pulse signal to obtain energy distribution data of the pulse signal, which is used to assist in judging signal characteristics and identifying signal type.

[0018] Furthermore, the electronic system is equipped with a clock circuit and an FPGA configuration memory. The clock circuit provides synchronization timing signals for each functional module inside the FPGA to ensure that it operates stably according to the set timing. The FPGA configuration memory is used to store the FPGA configuration program and loads the configuration program into the FPGA to initialize the logic of each functional module when the system is powered on.

[0019] Furthermore, the communication interface module is an Ethernet communication module. The Ethernet communication module converts the counting data and energy spectrum data processed by the FPGA module into network signals and transmits them to the host computer in accordance with the TCP / IP protocol, thereby realizing high-speed remote data transmission between the device and the host computer.

[0020] Furthermore, the low-ripple power supply module provides a stable, low-noise DC power supply to the charge-sensitive preamplifier, the pole-zero cancellation circuit, the pulse conditioning circuit, and the FPGA module, and can provide power outputs of different voltage specifications according to the needs of different modules, so as to ensure that each module works normally and avoid interference of power supply noise on signal processing.

[0021] Beneficial effects: 1. Compared with existing technologies, this invention achieves synchronous and parallel acquisition and reliable counting of multi-channel signals by setting multiple independent signal processing channels corresponding to "detector 1, detector 2... detector n": each signal is sequentially converted and amplified by a charge-sensitive preamplifier, the waveform is corrected by a pole-zero cancellation circuit, and then a standard pulse is output by a pulse conditioning module, which is sent to "counting module channel 1, counting module channel 2... counting module channel n" in the FPGA for parallel counting. The counting result is written to the "n-channel data RAM" buffer and runs stably under the protection of clock and Flash configuration. Finally, it is transmitted to the host computer via Ethernet module according to TCP / IP. At the same time, a low-ripple power supply module supplies power to each stage to reduce noise interference, ensuring the integrity and stability of multi-detector counting data acquisition from the structure and data flow path.

[0022] 2. This invention possesses stronger pulse throughput and counting accuracy in high count rate scenarios. The key lies in the introduction of a combined processing chain of "pole-zero cancellation + shaping and conditioning" at the front end: The pole-zero cancellation circuit compensates for the undershoot and distortion of the pre-amplified pulse through an RC network and shortens the time constant τ to about 40ns, corresponding to a pulse width of about 160ns, in order to suppress baseline rise caused by pulse accumulation, thereby creating cleaner input conditions for subsequent conditioning and counting; Subsequently, the pulse conditioning circuit shapes and filters the signal and outputs a pulse shape that is easy to count, enabling the FPGA counting module to obtain counting data with a lower error rate under parallel processing, thus improving the overall reliability of the measurement results.

[0023] 3. This invention significantly simplifies the neutron energy spectrum measurement process and reduces measurement deviations caused by neutron field instability. Its technical basis lies in the system of "single moderator with multiple detectors + parallel electronics for one-time measurement and full acquisition": Compared with traditional multi-sphere spectrometers that require replacing different moderator spheres one by one and performing time-division measurements, this invention arranges multiple detectors within a single moderator and completes the counting and acquisition of all channels at once. The data is then uploaded to the host computer in real time for spectrum interpretation, thereby reducing handling and replacement operations, shortening measurement time, and reducing inconsistency errors introduced by multiple measurements. Combined with the fast calculation capabilities of the spectrum interpretation software, it can achieve online near real-time acquisition of energy spectrum results, further improving the efficiency and usability of on-site neutron energy spectrum measurement. Attached Figure Description

[0024] Figure 1 This is a diagram showing the overall architecture of the electronic system in this invention; Figure 2 This is a diagram of the internal program logic architecture of the FPGA module in this invention. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Example 1 This embodiment is used to illustrate the basic structure and working principle of the present invention, aiming to clearly reveal the core technical solution of the present invention and ensure its feasibility.

[0027] This embodiment provides an electronic system for a single-sphere neutron spectrometer, including a detection system electronics system and a spectrum interpretation system.

[0028] The detection system includes a moderator and multiple thermal neutron detectors embedded at different positions within the moderator. These thermal neutron detectors convert the neutron radiation from the measured neutron field into pulse signals recognizable by the electronic system. For ease of explanation, the multiple thermal neutron detectors are referred to sequentially as detector 1, detector 2, through detector n.

[0029] The electronic system includes multiple front-end signal conversion circuits, multiple pulse conditioning circuits, an FPGA module, a communication interface module, and a low-ripple power supply module. Each front-end signal conversion circuit corresponds to a thermal neutron detector and includes a charge-sensitive preamplifier and a pole-zero cancellation circuit. The charge-sensitive preamplifier converts the weak charge signal output from the corresponding thermal neutron detector into a voltage signal and performs preliminary amplification. The pole-zero cancellation circuit is connected to the output of the charge-sensitive preamplifier and is used to compensate for and correct the distortion generated during the pre-processing stage, making the output pulse closer to the ideal decay exponential pulse and providing a stable input for subsequent conditioning.

[0030] Each pulse conditioning circuit is connected to the output of the corresponding pole-zero cancellation circuit to shape and filter the calibrated pulse signal and output a square wave signal for counting. Each square wave signal is sent as a multi-channel input to the FPGA module, thereby ensuring that the multi-channel signals from detector 1, detector 2 to detector n are processed independently and in parallel.

[0031] The FPGA module connects to the outputs of all pulse conditioning circuits and is used for parallel counting and data processing of multi-channel square wave signals. The FPGA module integrates counting module channel 1, counting module channel 2, up to counting module channel n, each receiving and counting the square wave signal from its corresponding channel. The FPGA module also includes an n-channel data RAM for temporarily storing the counting data from each counting module, and an energy spectrum acquisition module for acquiring and processing energy spectrum-related data from the pulse signals. Finally, the FPGA module includes a data communication module that reads the counting data from the n-channel data RAM and receives the energy spectrum data output from the energy spectrum acquisition module, organizing and encapsulating the counting and energy spectrum data to form data for transmission.

[0032] The communication interface module connects to the FPGA module, converting the data output from the FPGA module into network signals and sending them to the host computer. The host computer is a computer. The communication interface module uses an Ethernet communication module, interacting with the host computer via the TCP / IP protocol, enabling real-time uploading and processing of counting and energy spectrum data. The low-ripple power supply module provides a stable, low-noise DC power supply for the charge-sensitive preamplifier, the zero-pole cancellation circuit, the pulse conditioning circuit, the FPGA module, and the Ethernet communication module, reducing the impact of power supply noise on weak pulse signals and improving the overall stability of the system.

[0033] The structure and signal flow described in this embodiment can be restored accordingly. Figure 1 The overall architecture of the electronic system shown is as follows: detectors 1, 2 to n are sequentially connected to a charge-sensitive preamplifier pole-zero cancellation circuit pulse conditioning module and output a square wave signal into the FPGA module. Within the FPGA module, counting modules 1, 2 to n count in parallel. The count data enters the n-channel data RAM. At the same time, the energy spectrum acquisition module acquires energy spectrum data. The count data and energy spectrum data are transmitted to the computer via the Ethernet communication module using the TCP / IP protocol. The low-ripple power supply module supplies power to each module.

[0034] Preferably, all thermal neutron detectors are coated. 6 LiF material is used in SiC semiconductor thermal neutron detectors. This configuration facilitates the stable supply of the detection system output signal to the corresponding charge-sensitive preamplifier, and enables synchronous measurements of detectors 1, 2, and n in conjunction with a multi-channel parallel processing architecture. Furthermore, due to... 6 The LiF-coated SiC semiconductor thermal neutron detector is an active detector that enables online measurements, acquiring neutron counts and energy spectra in real time.

[0035] Example 2 Based on Example 1, this example further optimizes the operation of the front-end signal conversion circuit and the pulse conditioning circuit to enhance the counting accuracy and pulse throughput under high count rate conditions.

[0036] The charge-sensitive preamplifier is used to read the weak charge signal output from the thermal neutron detector and perform charge-to-voltage conversion and preliminary amplification, thereby providing a voltage pulse with sufficient amplitude for subsequent circuit processing. The pole-zero cancellation circuit compensates for potential undershoot and distortion in the preamplified pulse and, by setting a corresponding time constant, shortens the pulse width, thus suppressing pulse accumulation and baseline rise under high-throughput conditions, making the pulse waveform input to the pulse conditioning circuit more stable.

[0037] The pulse conditioning circuit performs shaping filtering and threshold discrimination on the pulse after it has been processed by the pole-zero cancellation circuit, so that the output pulse is converted into a square wave signal for counting. The circuit ensures that the square wave signal meets the counting input requirements of the FPGA module in terms of amplitude and width, thereby improving the effective counting rate and reducing the false counting rate.

[0038] Example 3 Based on Examples 1 and 2, this example further optimizes the internal program logic architecture of the FPGA module.

[0039] The FVBPGA module operates in parallel, from counting module channel 1 to counting module channel n, driven by a high-speed clock. Each counting module receives a square wave signal output from its corresponding pulse conditioning circuit and identifies and counts the effective rising edge of the square wave, accumulating the count value for the corresponding channel within a predetermined measurement time. The count data output by the counting module is temporarily stored in the n-channel data RAM. The data communication module is bidirectionally connected to the n-channel data RAM, reading the count data from the n-channel data RAM, encapsulating it, and then outputting it to the communication interface module. The high-speed clock provides a unified timing reference for the counting module, the n-channel data RAM, and the data communication module, enabling stable operation of multi-channel counting and buffer read / write within the same timing framework, thereby achieving... Figure 2 The connection relationship and data flow logic between the counting module group, the n-channel data RAM, and the data communication module are shown.

[0040] Meanwhile, the energy spectrum acquisition module works in parallel with the multi-channel counter within the FPGA module. The energy spectrum data output by the energy spectrum acquisition module enters the data communication module, is encapsulated together with the counting data read from the n-channel data RAM, and is then transmitted to the host computer through the communication interface module.

[0041] Example 4 Based on any of the embodiments 1 to 3, this embodiment further optimizes the clock circuit FPGA configuration memory communication interface module and the low ripple power supply module to ensure long-term stable operation of the system and meet online measurement requirements.

[0042] The clock circuit provides synchronization signals to the various functional modules within the FPGA module, forming a high-speed clock to ensure that counting module channel 1, counting module channel 2, and so on up to counting module channel n, along with the n-channel data RAM and data communication module, operate stably according to the set timing. The FPGA configuration memory stores the FPGA configuration program. Upon system power-on, the FPGA configuration memory loads the configuration program into the FPGA module to initialize the logical relationships and parameter settings of each functional module. The FPGA configuration memory can be implemented using Flash memory.

[0043] The communication interface module is an Ethernet communication module, connected to the data communication module. It converts the data output from the data communication module into network signals and transmits them to the host computer via TCP / IP protocol, enabling real-time remote transmission and interaction of counting and energy spectrum data. The low-ripple power supply module provides a stable, low-noise DC power supply for the charge-sensitive preamplifier, zero-pole cancellation circuit, pulse conditioning circuit, FPGA module, Ethernet communication module, clock circuit, FPGA configuration memory, and can provide different voltage outputs according to the needs of each module, such as ±12V, 5V, 3.3V, 1.8V, and 1.2V, thereby reducing the impact of power supply noise on weak pulse signals and improving the system's measurement stability.

[0044] Example 5 In this embodiment, the single-sphere neutron spectrometer electronic system of the present invention uses n=16 detectors and the measurement time window is set to 1 second, that is, every 1 second, a frame of measurement results containing all 16 channel count data and corresponding neutron energy spectrum data is output.

[0045] All 16 detectors are connected to the signal acquisition and processing unit of the electronics system through front-end circuits; the output pulse signal of each detector is sequentially processed by the preamplifier, main amplifier, filtering and shaping circuit of the corresponding channel and then input into the counting module.

[0046] The electronic system base is equipped with an input power interface and a signal output interface; an external +12V DC power supply is provided and converted by a voltage regulator module to produce the ±5V and ±12V low-voltage power supplies required for each stage and the high-voltage bias power supply for the detector (1000V in this embodiment).

[0047] The high-voltage power supplies for the 16 detectors are connected in parallel and uniformly provided by an internal high-voltage module to ensure consistent bias across all channels. Communication is via a wired high-speed serial interface (preferably Ethernet or USB), transmitting data per second to a host computer for storage and display through the signal output interface.

[0048] In this embodiment, the host computer is mainly used to receive and record real-time data, and can also perform online analysis and presentation of the energy spectrum. The connection between the detector and the front-end circuit uses a low-noise coaxial cable, which has a short connection distance and good shielding to reduce signal transmission loss and interference.

[0049] During the test, the intensity of the neutron source was changed to simulate low, medium, and high count rate conditions, and the system was kept running stably for performance evaluation.

[0050] The detector generates a charge signal upon receiving neutron radiation, which is amplified and shaped by the front-end to present a steep, narrow pulse waveform. The analog signal pulse width corresponding to each neutron event is approximately 1µs, primarily determined by the time constant setting of the front-end amplifier. The shaped pulse amplitude is related to the neutron event energy; when the pulse amplitude exceeds the discrimination threshold, it indicates a valid neutron detection event. The discrimination circuit converts each valid pulse into a fixed-width digital square wave signal output for counting and time stamping.

[0051] In this embodiment, the digital pulse width is set to 1–2µs (square wave duration), which is slightly larger than the analog pulse width, to ensure that only one digital pulse is generated during the entire duration of an event, thereby avoiding the same event being counted repeatedly.

[0052] The rising edge of the digital pulse corresponds to the moment when the detector pulse signal passes the threshold for discrimination. Because the rising edge of the pulse after front-end shaping is very steep and has low noise, the rising edge timing jitter is minimal—the measured standard deviation of the digital pulse rising edge jitter relative to the actual event occurrence time is approximately 20 ns. This high time resolution ensures accurate pulse timing for each channel during simultaneous multi-channel counting, with negligible event time synchronization errors between different channels. These waveforms and timing parameters demonstrate that the front-end electronics of this system can respond quickly and accurately to neutron pulses, laying the foundation for stable measurements at high count rates.

[0053] This embodiment comprehensively tests the parallel counting capability of the electronic system, including the evaluation of the counting consistency and count loss rate of each channel at low, medium and high count rates.

[0054] First, tests were conducted under low count rate conditions: the system was placed in a weak neutron field environment, with an average count rate of approximately 50 cps for each channel. After more than 24 hours of continuous measurement, the measured data showed that the count readings of each channel increased uniformly and steadily. No count omissions were found in the system under low count rates, and the count loss rate was approximately 0, meaning that every neutron pulse event was reliably recorded.

[0055] Secondly, tests were conducted under moderate count rates: Analog signals were input, achieving a count rate of 100 cps per channel. At this count level, the count results across all channels maintained good consistency. The distribution of counts per second across the 16 channels showed that each channel deviated from the overall average by less than 5%, with no single channel exhibiting significant deviation, indicating that the electronic system maintained balanced performance even when processing higher counts in parallel. Simultaneously, comparing the count input with the recorded output revealed almost no lost count events at this count rate, with a statistically low lost count rate of less than 0.1%, and the counting was essentially linear without saturation. In other words, approximately a thousand pulses per second were accurately counted into the corresponding channel's data frame.

[0056] Secondly, tests were conducted under moderate count rates: using analog input signals, the count rate per channel was approximately 1 × 10^3 cps (total count rate approximately 1.6 × 10^4 cps). At this count level, the count results across channels maintained good consistency. The distribution of count values ​​per second across the 16 channels showed that the deviation of each channel from the overall average was within 5%, with no single channel exhibiting significant deviation, indicating that the electronic system maintained balanced performance even when processing higher counts in parallel. Simultaneously, comparing the count input with the recorded output revealed that the system experienced almost no lost count events at this count rate, with a statistically low lost count rate of less than 0.1%, and the counting was essentially linear without saturation. In other words, approximately one thousand pulses per second were accurately counted into the corresponding channel's data frame.

[0057] Finally, the system's extreme parallel counting capability was tested under high count rate conditions. By inputting an analog signal, when the signal generation rate reached 10^6 cps, the count rate of each channel approached 1×10^6 cps, and the total count rate of 16 channels was approximately 1.6×10^7 cps. Under such a high counting load, the count readings of each channel remained essentially consistent.

[0058] Actual measurements show that the count values ​​per second for each channel remained largely unbalanced, with deviations below 10%, and no severe lag was observed in any single channel. This indicates that the system's multi-channel parallel architecture allows each channel to process events independently and simultaneously without interference, even at high count rates.

[0059] When the count rate is slightly below this peak, the system still achieves zero count misses. Overall, the count rate per channel ranges from a few cps to 10 within the design range. 4 The counting response of this electronic system maintains a basically linear growth, with no significant dead-time effect causing saturation.

[0060] The test results above demonstrate that the multi-channel parallel counting design adopted in this invention is effective. Each channel exhibits a highly consistent counting response and an extremely low event omission rate at different count rates, ensuring reliable measurement of the spectrometer over a wide dynamic range.

[0061] This embodiment of the system generates one frame of counting and energy spectrum data per second, which needs to be uploaded to the host computer in real time. Therefore, the stability and timeliness of data transmission were tested and evaluated. The system's data upload cycle is a fixed 1.000s: the internal high-precision clock controls the frame rate, ensuring that the time interval between two data output frames is stable at approximately 1 second. After continuous operation for a period of time, the variation in the time interval between adjacent frames is within the millisecond range, and the standard deviation of the period deviation between frames is less than 1ms, indicating that the data frame cycle is very stable. Each frame of data contains the count values ​​of 16 channels and the energy spectrum distribution calculated and recorded within the corresponding time period. In actual implementation, the length of each frame of data in this embodiment is approximately 100-200 bytes. Transmitting this amount of data through high-speed interfaces such as Ethernet or USB is very easy: at a frame rate of 1Hz, the average data flow rate is less than 0.2kB per second, occupying extremely low bandwidth.

[0062] Therefore, data upload will not cause interface congestion or accumulated latency. Testing showed that the total latency from the completion of each frame measurement to the successful transmission and reception of data to the host computer is approximately 10ms, mainly including the time required for the microcontroller / FPGA to process the entire frame of data and for interface transmission. This latency is far less than the measurement cycle (only on the order of 1%), and therefore will not affect the system's real-time requirements.

[0063] To assess transmission reliability, the system was run continuously for several hours under full load counting conditions, and the sequence of uploaded data frames was recorded. The results showed that all frames arrived on time, with no frame loss or order errors, and the data transmission process was stable and reliable. Under wired connection conditions, it exhibited good anti-interference performance with no data packet errors; even in a typical laboratory electromagnetic environment (with other equipment operating), frame data was not lost or corrupted.

[0064] Preferably, the system can also improve its anti-interference margin by adding a simple check and retransmission mechanism to the communication protocol. Overall, the data upload capability of this electronic system fully meets the real-time transmission requirement of one frame of data per second, with low latency, high stability, and no data loss, providing a guarantee for the subsequent accurate reconstruction of the neutron energy spectrum by the host computer.

[0065] To ensure accurate and reliable counting, this embodiment tested and evaluated the ripple noise of the system power supply and the resulting false counts. The electronic system employs a multi-stage power supply filtering and regulation design: the front-end analog circuit of the detector is powered by a low-noise linear regulated power supply, and decoupling capacitors are added to each channel's power supply branch to smooth the voltage. Oscilloscope measurements showed that under full load operation of 16 channels, the output ripple of the analog power supply (±5V, ±12V, etc.) was less than 10mV peak-to-peak, indicating a very small ripple voltage. The high-voltage bias power supply uses a dedicated high-voltage module and is regulated by a filtering network; at approximately 1000V bias, its ripple is approximately 0.5V peak-to-peak (relative ripple less than 0.05%). Such low power supply ripple ensures stable operating voltage for the detector and front-end amplifier, preventing significant baseline drift or noise spikes. The signal baseline output by the front-end amplifier is very flat in steady state, and the noise level (RMS value) of each channel is measured to be only a few percentage points or even lower than the threshold amplitude. Therefore, power supply noise does not interfere with the detector's threshold discrimination and will not trigger false counts. To further verify this, we conducted a long-term monitoring experiment under neutron-free radiation input conditions: the detector was placed in the ambient background. The system was powered on and maintained at all operating voltages for continuous monitoring for 1 hour. The results showed that no counting pulse events were recorded in any of the 16 channels, and the count readings remained zero throughout, with no false counts caused by electronic noise or power supply ripple. In a normal experimental environment (without shielding), the extremely low count rates occasionally recorded by each channel were entirely attributable to natural background neutron radiation (e.g., less than a few times per hour). These counts were consistent with the theoretically expected background level and were not caused by electronic system noise. Therefore, it can be determined that the power supply quality and anti-interference design of the electronic system of this invention are sufficient, ensuring extremely low front-end baseline noise while avoiding false counts caused by power supply ripple or external electromagnetic interference.

[0066] The above experimental data fully demonstrates the authenticity and feasibility of this embodiment: those skilled in the art can fully realize the 16-channel single-sphere neutron spectrometer electronics system and obtain the performance indicators as described above.

[0067] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electronic system for a single-sphere neutron spectrometer, comprising a detection system, an electronics system, and a spectral interpretation system, characterized in that: The detection system includes a single moderator and multiple thermal neutron detectors embedded at different positions within the moderator, used to convert the neutron radiation of the measured neutron field into pulse signals recognizable by the electronic system. The electronic system includes multiple front-end signal conversion circuits, multiple pulse conditioning circuits, an FPGA module, a communication interface module, and a low-ripple power supply module. The front-end signal conversion circuit, each corresponding to one of the thermal neutron detectors, includes a charge-sensitive preamplifier and a pole-zero cancellation circuit, used to convert the weak charge signal output by the thermal neutron detector into a voltage signal and perform preliminary amplification, while compensating for and correcting the distortion generated during the detector and preamplification process. The pulse conditioning circuit is connected to the output of the front-end signal conversion circuit and is used to perform waveform shaping and filtering on the calibrated pulse signal to condition the pulse signal into a standard pulse that meets the subsequent counting requirements. Each detector signal corresponds to an independent pulse conditioning circuit to ensure independent parallel processing of multi-channel signals. The FPGA module is connected to the output of all the pulse conditioning circuits and is used to perform parallel counting and data processing of multi-channel pulse signals. The FPGA module integrates multiple pulse counting modules corresponding to each channel, a data storage device for temporarily storing multi-channel counting data, and an energy spectrum acquisition module for acquiring pulse energy spectrum information. It is also equipped with a clock and configuration storage unit, thereby realizing the acquisition and temporary storage of pulse count values ​​of each channel, as well as the synchronous acquisition of pulse energy spectrum data, and ensuring that each functional module of the FPGA operates according to a predetermined logical timing. The communication interface module is connected to the FPGA module, converts the counting data and energy spectrum data processed by the FPGA module into network signals, and transmits them to the host computer via TCP / IP protocol to achieve high-speed remote data transmission and interaction. The low-ripple power supply module provides a stable, low-noise DC power supply to each module of the electronic system, avoiding interference from power supply ripple on signal processing. The spectrum interpretation system is spectrum interpretation software running on a host computer, used to calculate the neutron energy spectrum based on the multi-channel counting data.

2. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The thermal neutron detectors are all coated. 6 SiC semiconductor thermal neutron detectors made of LiF material.

3. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The output signal of each thermal neutron detector is processed sequentially by a corresponding charge-sensitive preamplifier and a pole-zero cancellation circuit. The charge-sensitive preamplifier converts the weak output charge signal into a voltage signal and amplifies it. The pole-zero cancellation circuit compensates for the undershoot distortion generated by the previous stage and shortens the pulse width to reduce the impact of pulse accumulation at high count rates.

4. The single-sphere neutron spectrometer electronic system according to claim 3, characterized in that, The pulse conditioning circuit performs waveform shaping and filtering on the pulse signal after it has been corrected by the pole-zero cancellation circuit, adjusting the amplitude and width of the pulse to a predetermined range to output a standard pulse signal that meets the counting requirements, and ensuring independent parallel processing of signals from each channel.

5. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The multiple pulse counting modules set within the FPGA module count the pulse signals of each channel and calculate the number of pulses per unit time to obtain the pulse count rate of the corresponding channel.

6. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The data storage device is used to temporarily store the counting data output by the multiple pulse counting modules. As a data cache unit, it coordinates the data transmission and processing rhythm within the system to ensure the orderly flow of multi-channel counting data within the system and provides temporary storage space for subsequent data transmission or further processing.

7. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The energy spectrum acquisition module works in parallel with the multiple pulse counting modules to acquire and process energy spectrum-related information of the pulse signal to obtain energy distribution data of the pulse signal, which is used to assist in judging signal characteristics and identifying signal type.

8. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The electronic system is equipped with a clock circuit and an FPGA configuration memory. The clock circuit provides synchronization timing signals for each functional module inside the FPGA to ensure that it works stably according to the set timing. The FPGA configuration memory is used to store the FPGA configuration program and loads the configuration program into the FPGA to initialize the logic of each functional module when the system is powered on.

9. The single-sphere neutron spectrometer electronic system according to claim 1, characterized in that, The communication interface module is an Ethernet communication module. The Ethernet communication module converts the counting data and energy spectrum data processed by the FPGA module into network signals and transmits them to the host computer in accordance with the TCP / IP protocol, thereby realizing high-speed remote data transmission between the device and the host computer.

10. The single-sphere neutron spectrometer electronic system according to any one of claims 1-9, characterized in that, The low-ripple power supply module provides a stable, low-noise DC power supply to the charge-sensitive preamplifier, pole-zero cancellation circuit, pulse conditioning circuit, and FPGA module, and can provide power outputs of different voltage specifications according to the needs of different modules to ensure that each module works normally and avoid interference from power supply noise to signal processing.

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