Based on multi-layer 10 B-film and fan-shaped architecture grazing incidence high-resolution neutron detector

Abstract

This invention belongs to the field of neutron detection technology, and relates to a method based on multilayer... 10 B-thin and fan-shaped architecture grazing incidence high-resolution neutron detector; containing multiple layers (10 layers or more) of 3μm to 8μm 10 B or 10 B4C thin film, neutron detection efficiency exceeding 40%, 8μm thick 10 The B4C layer forms a natural internal shield; the fan-shaped architecture with multi-wire proportional cells achieves "sub-millimeter resolution + uniformity"; the grazing incidence structure increases the instantaneous count rate to over several hundred kHz / mm²; the readout electronics system adopts a two-level architecture to reduce noise and improve data processing efficiency; this detector is suitable for high-end scientific facilities, can improve the level of neutron detection, and has broad application prospects in many fields.

Description

Technical Field

[0001] This invention relates to the field of neutron detection technology, specifically to a method based on multilayer... 10 B-thin film and fan-shaped architecture grazing incidence high-resolution neutron detector. Background Technology

[0002] Neutrons, as electrically neutral and highly penetrating "nuclear probes," have played a vital role in fields such as nuclear fission, activation analysis, isotope production, semiconductor doping, irradiation processing, tumor therapy, and radiation breeding, bringing significant economic and social benefits to medicine, industry, and agriculture. Complementing X-rays, neutron scattering, with its unique advantages such as isotope identification, deep penetration, and non-destructiveness, has become an indispensable research tool in fields such as condensed matter physics, chemistry, life sciences, and materials science.

[0003] The neutron science facility is being upgraded along two parallel tracks: the "high-flux research reactor" and the "split neutron source," providing an original innovation platform for cutting-edge technologies such as nanotechnology, information, space, and medicine. With the second phase of CSNS, the upgrade of CARR, and the expansion of the capabilities of the Mianyang Research Reactor (CMRR), the demand for neutron scattering applications in China has grown rapidly, creating an urgent need for the independent controllability of key components such as position-sensitive neutron detectors.

[0004] As a core spectrometer for studying thin film structures and interface phenomena, the multifunctional neutron reflectometer requires the detector to achieve sub-millimeter-level position resolution along the normal direction of the sample surface and withstand instantaneous count rates as high as hundreds of kHz / mm²; currently, the mainstream international detectors still rely on 3 He position sensitive tube or ZnS:Ag / 6 LiF scintillation screens are available, but traditional technologies are no longer sufficient to meet the stringent requirements of "0.5mm FWHM + 100kHz / mm²" set by ESS's FREIA, ESTIA, and CSNS Phase II liquid reflectometers under construction.

[0005] Traditional neutron scattering spectrometers mostly use high-pressure gas. 3 He gas detectors, such as multi-position sensitive high-pressure gas detectors 3 He proportional tube array or high pressure 3 He multi-wire proportional chamber; although this type of detector has large area, high detection efficiency, good n / γ suppression ratio, and operational stability, in recent years... 3 Helium gas resources are severely insufficient in supply, and prices have increased more than tenfold, making the construction of large-scale detection systems virtually impossible, thus triggering a wave of "de-emergence" efforts. 3 He's technological wave; 10 B-film MWPC is characterized by its infinitely expandable solid boron layer, lack of high-pressure sealing requirements, and natural boron content. 10With advantages such as the ability to be commercially viable when concentrated to 90%, B has become the most promising alternative route.

[0006] although 10 B-film MWPC inherits 3 While He-cells offer all the advantages of large area, two-dimensional position resolution, high n / γ suppression, radiation resistance, and high count tolerance, how to further improve their detection efficiency, position resolution, and count rate to meet the needs of upgrading next-generation neutron source facilities and cutting-edge scientific research remains a critical issue that urgently needs to be addressed. Summary of the Invention

[0007] To address the aforementioned problems, this invention aims to provide a multi-layer... 10 B-thin and sector-structured grazing incidence high-resolution neutron detectors can be applied in nuclear physics research facilities in fields such as condensed matter physics, chemistry, life sciences, and materials science. They can meet the needs of equipment such as neutron scattering spectrometers for high position resolution, high count rate, and high efficiency neutron detectors, and help upgrade my country's neutron source facilities and advance cutting-edge scientific research.

[0008] The technical solution adopted in this invention is: a multi-layer... 10 B-thin and fan-shaped architecture grazing incidence high-resolution neutron detectors include: Multi-story 10 B. Thin film structure, each layer 10 B film or 10 The B4C thin film is 8 μm thick and is used to convert incident thermal neutrons into detectable secondary particles. A fan-shaped multi-wire proportional chamber is used to collect secondary particles and achieve position resolution; The readout electronics system is used to process and output detector signals.

[0009] The multi-layer 10 The B-thin thin film structure has 10 or more layers, with an overall neutron detection efficiency greater than 40%, and each layer... 10 B film or 10 B4C thin films were prepared by magnetron sputtering.

[0010] The multi-filament proportional chamber of the sector-structured architecture includes: Multiple independent multi-wire proportional chamber units, each unit containing an independent anode wire, readout bar, and boron-coated plate, with each independent unit arranged in a fan-shaped distribution; The incident aluminum plate is designed with a knife-edge shape to reduce dead zone and wall effect; The high-voltage distribution circuit adopts a partitioning scheme to ensure uniform electric field strength of each anode wire.

[0011] The high voltage distribution circuit of the anode wire achieves gradient voltage reduction through a precision resistor chain circuit. Multiple high-resistance precision resistors are connected in series, and the total high voltage is applied to both ends of the resistor chain. Voltage division is drawn from the nodes to achieve gradient voltage reduction. The total current is stabilized at 75μA, and the resistance value is selected in steps according to the voltage difference range of 11.7V.

[0012] The readout electronics system adopts a two-tier architecture of "front-end signal processing - back-end digital readout", including: The front-end signal processing module adopts an ASIC-based readout scheme and is responsible for charge integration amplification and filtering shaping; The back-end digital readout module uses an FPGA as the core processing unit and integrates a high-precision ADC to realize two-dimensional position measurement and high-speed data transmission.

[0013] In the aforementioned front-end signal processing module, a single front-end module integrates two 32-channel ASIC chips, with a charge sensitivity of 1mV / fC, enabling parallel processing of 64 channels.

[0014] In the back-end digital readout module, the FPGA core processing unit integrates four high-precision ADCs. Each ADC can acquire 32 channels of signals, and the data transmission rate reaches 1Gb / s.

[0015] The multi-layer 10 In B thin film structures, monolayer 10 The B4C thin film, with a thickness of 8 μm, was prepared by magnetron sputtering, with the addition of a gradient buffer layer and stress relief groove, and subsequent vacuum annealing to control the warpage to within 10 µm.

[0016] The detector employs a grazing incidence method, increasing the path of neutrons in the conversion layer and improving the interaction between neutrons and... 10 The probability of a B4C reaction is improved by optimizing the incident angle to increase detection efficiency and achieve sub-millimeter-level position resolution. Simultaneously, the neutron and conversion layer... 10 B4C also forms an angle θ, and 10 The path of the B4C conversion layer reaction, starting from the vertically incident s, extends to s / cosθ, where the neutron interacts with the conversion layer. 10 The B4C reaction pathway increases, allowing more neutrons to react with... 10 B4C reacts, thereby improving the detection efficiency of neutrons.

[0017] The detector is suitable for multifunctional neutron reflectometers, enabling sub-millimeter-level position resolution in the normal direction of the sample surface and withstanding instantaneous count rates up to 100 kHz / mm².

[0018] This application proposes a multi-layered... 10The grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, through innovative technical design, achieves significant improvements in detection efficiency, position resolution, and count rate, and has the following beneficial effects: This invention employs multiple layers (10 layers or more). 10 B film or 10 B4C thin-film structures, with each layer ranging from 3 μm to 8 μm in thickness, were fabricated using magnetron sputtering and achieved an overall neutron detection efficiency greater than 40%. The 8 μm thick layer was particularly effective. 10 The B4C layer not only improves conversion efficiency, but also forms a natural internal shield by absorbing unreacted neutrons, reducing the scattering background of the detector material by an order of magnitude.

[0019] This invention features a multi-wire proportional chamber design with a fan-shaped architecture, arranging multiple anode wires in a fan-shaped distribution. The incident aluminum plate is designed with a knife-edge shape, reducing dead zones and mitigating wall effects. Simultaneously, the high-voltage distribution circuit employs a partitioned scheme to ensure uniform electric field intensity across all anode wires, achieving sub-millimeter resolution and uniformity. The grazing incidence method further optimizes position resolution, enabling the detector to easily achieve sub-millimeter accuracy in the direction most important to the reflectometer—perpendicular to the sample surface.

[0020] This invention's grazing incidence structure distributes neutron counting across multiple anode wires, reducing the counting pressure on a single channel and significantly improving the detector's instantaneous count rate. Combined with an optimized readout electronics system, the detector can withstand instantaneous count rates of hundreds of kHz / mm² or even higher, meeting the requirements of next-generation neutron source facilities for the extreme performance specifications of high-brightness neutron sources.

[0021] The readout electronics system of this invention adopts a two-tier architecture of "front-end signal processing - back-end digital readout". The front-end signal processing module uses an ASIC-based readout scheme, responsible for charge integration amplification and filtering shaping; the back-end digital readout module uses an FPGA as the core processing unit, integrating a high-precision ADC to realize two-dimensional position measurement and high-speed data transmission. This design not only reduces system noise, but also improves the efficiency and flexibility of data processing.

[0022] The grazing incidence high-resolution neutron detector proposed in this invention is suitable for high-end scientific facilities such as multifunctional neutron reflectors, and can significantly improve my country's neutron detection technology, promoting the independent controllability and performance leap of high-end boron-coated neutron detectors. At the same time, this detector has broad application prospects in materials science, life sciences, condensed matter physics, and other fields, providing strong technical support for cutting-edge scientific research in my country. Attached Figure Description

[0023] Figure 1 This invention relates to a single layer¹ 0 B thickness, multi-layer¹ 0The diagram illustrating the conversion efficiency of B-type thermal neutrons shows the relationship between single-layer and multi-layer ¹ 0 The relationship between the thermal neutron conversion efficiency of B thin films and the film thickness provides a theoretical basis for the design of multilayer thin film structures. Figure 2 This is a schematic diagram of the detector structure of the present invention, which intuitively shows the overall structure of the detector, including multiple layers. 10 B. The relative positions of the thin-film structure, the fan-shaped architecture of the multi-wire proportional chamber, and the readout electronics system; Figure 3 This is a schematic diagram of the research and technical route of the present invention, illustrating the research process and technical route of the present invention, and providing a guiding framework for the development of detectors; Figure 4 This is a diagram showing the influence of the grazing incidence method on the position in this invention. It analyzes the impact of the incident angle on the position resolution capability of the detector under the grazing incidence method, providing a basis for optimizing the detector design. Figure 5 This is a schematic diagram of the energy loss relationship of secondary particles in the gas in this invention; Figure 6 In this invention 10 A schematic diagram illustrating the simulated relationship between B4C thickness and secondary particle emission angle; Figure 7 The schematic diagrams of single-layer and double-layer nuclear reactions in this invention illustrate the simulation results of the energy loss process of secondary particles in the gas and the emission angle, providing intuitive support for understanding the working principle of the detector. Figure 8 This is a schematic diagram of the multi-wire proportional chamber sector structure in this invention, which shows in detail the sector structure design of the multi-wire proportional chamber, including the arrangement of the anode wires and the characteristics of the electric field distribution. Figure 9 This is a schematic diagram of the knife edge design of the incident surface of the 2mm thick aluminum plate in this invention, showing the details of the knife edge design of the incident surface aluminum plate, including the knife edge shape, size and processing requirements, which aims to reduce the dead zone and reduce the wall effect; Figure 10 This is a framework diagram of the readout electronics system in this invention, showing the overall architecture and signal processing flow of the readout electronics system, including the composition and function of the front-end signal processing module and the back-end digital readout module; Figure 11 This is a schematic diagram of the structure and manufacturing principle of the key component blade in this invention, which introduces the mechanical structure and manufacturing process of the key component blade, including material selection, processing flow and quality control points; Figure 12 The schematic diagram of the detector signal characteristics in this invention shows the results of the characteristic analysis of the detector signal, including the signal waveform, signal-to-noise ratio optimization measures, and effect evaluation. Figure 13The schematic diagram of the position resolution measurement of the small prototype in this invention shows the performance of the small prototype in position resolution testing, including the test method, test results and performance evaluation, and verifies the optimization effect of the grazing incidence scheme on position resolution. Detailed Implementation

[0024] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings: like Figure 1-13 As shown, this invention proposes a method based on multilayer... 10 The grazing incidence high-resolution neutron detector based on a thin film and fan-shaped architecture is designed to meet the urgent need of multifunctional neutron reflectors for high position resolution and high count rate neutron detectors; among which... Figure 1 Showcasing single-layer and multi-layer¹ 0 The relationship between the thermal neutron conversion efficiency of B thin films and the film thickness provides a theoretical basis for the design of multilayer thin film structures. Figure 2 The overall structure of the detector is visually displayed, including multiple layers. 10 B. The relative positions of the thin-film structure, the fan-shaped architecture of the multi-wire proportional chamber, and the readout electronics system; Figure 3 The research process and technical route of this invention are summarized, providing a guiding framework for the development of detectors; Figure 4 The influence of the incident angle on the detector's position resolution under grazing incidence mode was analyzed, providing a basis for optimizing detector design; Figure 5-7 The simulation results show the energy loss process of secondary particles in the gas and the emission angle, providing intuitive support for understanding the working principle of the detector; Figure 8 The fan-shaped structure design of the multi-wire proportional chamber is shown in detail, including the arrangement of the anode wires and the characteristics of the electric field distribution. Figure 9 The details of the blade design on the incident aluminum plate are shown, including the blade shape, size and processing requirements, which aim to reduce dead zone and reduce wall effect; Figure 10 The overall architecture and signal processing flow of the readout electronics system are demonstrated, including the composition and function of the front-end signal processing module and the back-end digital readout module; Figure 11 The mechanical structure and manufacturing process of the key component, the blade, are demonstrated in practice, including material selection, processing flow, and key points of quality control. Figure 12 The results of the characteristic analysis of the detector signal are presented, including signal waveform, signal-to-noise ratio optimization measures and effect evaluation; Figure 13 The performance of the small prototype in position resolution testing was demonstrated, including the testing methods, results, and performance evaluation. The grazing incidence scheme was verified for its optimization effect on position resolution. The specific structure is as follows: P1. Overall structure of the detector The grazing incidence high-resolution neutron detector of the present invention mainly consists of multiple layers 10The system consists of three main parts: a thin-film structure, a fan-shaped multi-wire proportional chamber, and a readout electronics system.

[0025] P2, Multi-layer 10 B. Thin film structure Thin film composition and thickness: multilayer 10 B-film structures consist of ten or fewer layers, each with a thickness of 3 μm to 8 μm. 10 B film or 10 B4C thin films are stacked together, such as Figure 1 As shown. Each thin film is prepared using a magnetron sputtering process to ensure uniformity and consistency. Single layer 10 The optimal thickness of B4C thin films is about 3 μm, but considering the actual process and performance requirements, this invention mainly studies the preparation process of 8 μm thickness.

[0026] Neutron conversion efficiency: 10 B reacts with thermal neutrons across a large cross-section, releasing α-ions after the reaction. 7 Li particles have a short range, and the theoretical conversion efficiency of a single-layer boron film is about 5%. By stacking multiple layers, the overall neutron detection efficiency can be increased to >40%, meeting the requirements of high-brightness neutron sources.

[0027] Fabrication Process: During the fabrication process, parameters such as the boron-to-carbon ratio, substrate temperature, argon pressure, and sputtering power must be strictly controlled to ensure film quality. For 8μm thick films, a gradient buffer layer and stress relief grooves need to be added, along with subsequent vacuum annealing to control warpage to within 10µm.

[0028] P3, multi-filament proportional chamber with fan-shaped structure Anode wire arrangement: The multi-wire proportional chamber's internal anode wires are arranged in a fan-shaped distribution, such as... Figure 8 As shown in the figure. This design helps optimize the electric field distribution and improve the collection efficiency of secondary particles.

[0029] Incident surface aluminum plate design: The incident surface aluminum plate is designed in a knife-edge shape, such as... Figure 9 As shown, the 2mm thick aluminum plate incident surface knife edge design is demonstrated to reduce the dead zone and reduce the wall effect, thereby increasing the effective detection area of ​​the detector.

[0030] High-voltage distribution circuit: The high-voltage distribution circuit adopts a partitioning scheme. The anode wire high-voltage distribution circuit achieves gradient voltage reduction through a precision resistor chain. Multiple high-resistance precision resistors are connected in series, and the total high voltage is applied to both ends of the resistor chain. Voltage division is drawn from the nodes to achieve gradient voltage reduction, ensuring that the electric field strength of each anode wire is uniform. The total current is about 75μA. The resistance value is selected in steps according to the voltage difference range of 11.7V to ensure the stability and uniformity of the electric field.

[0031] P4, Readout Electronics System System Architecture: The readout electronics system adopts a two-tier architecture of "front-end signal processing - back-end digital readout", such as... Figure 10 The diagram shows the logical framework of the readout electronics system, with the front end responsible for the initial processing of signals and the back end responsible for the digitization and transmission of signals.

[0032] Front-end signal processing module: The front-end signal processing module adopts an ASIC-based readout scheme. A single front-end module integrates two 32-channel ASIC chips with a charge sensitivity of 1mV / fC, enabling parallel processing of 64 channels. This module is responsible for charge integration amplification and filtering shaping to improve the signal-to-noise ratio.

[0033] Back-end digital readout module: The back-end digital readout module uses FPGA as the core processing unit and integrates four high-precision ADCs. Each ADC can acquire 32 channels of signals and the data transmission rate reaches 1Gb / s. This module is responsible for two-dimensional position measurement and high-speed data transmission to meet the needs of large data volume processing.

[0034] P5, Detector performance optimization Grazing incidence scheme: The detector adopts a grazing incidence method, which improves detection efficiency and achieves sub-millimeter-level position resolution by optimizing the incident angle, such as... Figure 4 The diagram illustrates the impact of grazing incidence on position. The intrinsic position resolution of multi-wire proportional chambers is typically on the order of millimeters. By employing grazing incidence geometry, adjacent events are significantly separated in the mechanical projection, thereby improving the resolution to the sub-millimeter level. More specifically, the detector uses grazing incidence, increasing the path of neutrons in the conversion layer and improving the interaction between neutrons and... 10 The probability of a B4C reaction is improved by optimizing the incident angle to increase detection efficiency and achieve sub-millimeter-level position resolution. Simultaneously, the neutron and conversion layer... 10 B4C also forms an angle θ, and 10 The path of the B4C conversion layer reaction, starting from the vertically incident s, extends to s / cosθ, where the neutron interacts with the conversion layer. 10 The B4C reaction pathway increases, allowing more neutrons to react with... 10 B4C reacts, thereby improving the detection efficiency of neutrons.

[0035] Signal Characteristic Study: In the experiment, the signal characteristics of the detector were studied in depth. It was found that the overall capacitance of the aluminum substrate readout strip was large, resulting in a weak strip signal and a low signal-to-noise ratio. By improving the voltage-resistant capacitor and introducing a charge-sensitive preamplifier, the anti-interference capability was enhanced. Simultaneously, optimizing the anode wire diameter and tension significantly improved the signal-to-noise ratio of the wire signal. Figure 11 and Figure 12 As shown, where Figure 11 The structure and fabrication of the key component, the blade, were demonstrated. Figure 12The study of detector signal characteristics was presented.

[0036] Example: like Figure 1-13 As shown, this embodiment is based on a multi-layer¹ 0 B-film and fan-shaped architecture grazing incidence high-resolution neutron detectors are suitable for multifunctional neutron reflectometers, enabling sub-millimeter-level position resolution in the normal direction of the sample surface and withstanding instantaneous count rates of up to hundreds of kHz / mm², meeting the needs of cutting-edge scientific research.

[0037] The detector in this embodiment is based on a multi-layer... 10 The implementation principle of the grazing incidence design with B-film and fan-shaped architecture is as follows: Multi-story 10 B. Thin film structure: Each layer 10 B film or 10 B4C thin films with a thickness of 3 μm to 8 μm were prepared by magnetron sputtering. 10 B reacts with thermal neutrons across a large cross-section, releasing α-neutrons in the reaction. 7 Li has a short range, much shorter than the neutron absorption length; by stacking "boron film-cathode-gas amplification" sandwich units, the efficiency saturation point can be approached without significantly increasing the structural complexity; ten units can increase the overall efficiency to >40%.

[0038] The multi-wire proportional chamber with a fan-shaped architecture includes multiple anode wires arranged in a fan-shaped distribution to collect secondary particles and achieve position resolution; the incident aluminum plate is designed in a knife-edge shape to reduce dead zones and wall effects; the high-voltage distribution circuit adopts a partitioning scheme to ensure uniform electric field strength of each anode wire.

[0039] The readout electronics system adopts a two-tier architecture of "front-end signal processing - back-end digital readout". The front-end signal processing module is responsible for charge integration amplification and filtering shaping; the back-end digital readout module is responsible for two-dimensional position measurement and high-speed data transmission.

[0040] The working principle of this embodiment is as follows: Neutron conversion, incident thermal neutrons and 10 Nuclear reactions occur in the B membrane, generating secondary particles (α and β). 7 Li).

[0041] Secondary particle collection involves the secondary particles entering a multi-wire proportional chamber with a fan-shaped structure. They are ionized in the working gas, and the ionized electrons move towards the anode wire under the influence of the field strength, generating an avalanche near the anode wire, which further amplifies the signal.

[0042] Signal amplification and processing: electrons avalanche near the anode wire, the electron signal is collected by the anode wire, and the ion signal is collected by the readout strip; the readout electronics system integrates, amplifies, filters, shapes, and digitally converts the electron / ion signal, and finally outputs the detector's position and energy information.

[0043] Grazing incidence optimization improves detection efficiency and achieves sub-millimeter position resolution by optimizing the incident angle.

[0044] The testing method for this embodiment is as follows: Position resolution test: A small prototype with a single-layer structure and an effective area of ​​100mm×100mm was used to conduct beam testing with a 128-channel commercial electronics system. The position resolution half width at half maximum (FWHM) was measured by scanning the slit with oblique incidence.

[0045] Detection efficiency test: The detector is irradiated with a standard neutron source, and the ratio of the number of neutrons detected per unit time to the number of incident neutrons is measured to calculate the detection efficiency.

[0046] Count rate capability test: Gradually increase the incident neutron beam intensity and measure the detector's performance at different count rates to evaluate its ability to withstand instantaneous count rates.

[0047] The test results and performance evaluation for this embodiment are as follows: Position resolution: The measured half-width at half-maximum (FWHM) of the position resolution are 0.50 mm, 0.74 mm and 0.85 mm, respectively, which meet the requirements for sub-millimeter position resolution.

[0048] Detection efficiency: 10 layers 10 The overall neutron detection efficiency of the B-thin film structure is greater than 40%, reaching the international advanced level.

[0049] Count rate capability: The detector can withstand instantaneous count rates of up to hundreds of kHz / mm², meeting the requirements of a multifunctional neutron reflector.

[0050] Stability and reliability: After long-term continuous testing, the detector performance is stable, with no obvious performance degradation or failure, and has high reliability.

[0051] This embodiment has multiple layers. 10 B. Thin film preparation: Multilayers were fabricated on an aluminum substrate using magnetron sputtering. 10 B or 10 B4C films, with each layer ranging from 3μm to 8μm in thickness, have warpage controlled to within 10µm by adding gradient buffer layers and stress relief grooves, along with subsequent vacuum annealing.

[0052] In this embodiment, the fan-shaped multi-wire proportional chamber assembly arranges multiple anode wires in a fan-shaped distribution and fixes them on the incident aluminum plate. The aluminum plate is designed with a knife-edge shape to reduce dead zones and wall effects. The high-voltage distribution circuit adopts a partitioning scheme and achieves gradient voltage reduction through a precision resistor chain to ensure uniform electric field strength of each anode wire.

[0053] In this embodiment, the readout electronics system configuration employs an ASIC-based readout scheme for the front-end signal processing module. Each front-end module integrates two 32-channel ASIC chips, enabling parallel processing of 64 channels. The back-end digital readout module uses an FPGA as its core processing unit, integrating four high-precision ADCs. Each ADC achieves 32-channel signal acquisition, with a data transmission rate reaching 1Gb / s.

[0054] The system integration and testing implemented in this way will involve multiple layers. 10 The B-thin-film structure, fan-shaped multi-wire proportional chamber, and readout electronics system are integrated together for overall testing and performance evaluation. The detector's performance is further improved by optimizing the incident angle and electronics system parameters.

[0055] The detector in this embodiment has a compact structure and superior performance, which can meet the requirements of multifunctional neutron reflectors for high position resolution and high count rate neutron detectors, and has broad application prospects.

Claims

1. A multi-layer-based 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... include: Multilayer 10 B thin film structure, each layer 10 B thin film or 10 B4C thin film thickness of 8 μm for converting incident thermal neutrons into detectable secondary particles; A fan-shaped multi-wire proportional chamber is used to collect secondary particles and achieve position resolution; The readout electronics system is used to process and output detector signals.

2. The multi-layer based method according to claim 1 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The multilayer 10 The B-thin thin film structure has 10 or more layers, with an overall neutron detection efficiency greater than 40%, and each layer... 10 B film or 10 B4C thin films were prepared by magnetron sputtering.

3. The multi-layer based method according to claim 1 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The multi-filament proportional chamber of the sector-structured architecture includes: Multiple independent multi-wire proportional chamber units, each unit containing an independent anode wire, readout bar, and boron-coated plate, with each independent unit arranged in a fan-shaped distribution; The incident aluminum plate is designed with a knife-edge shape to reduce dead zone and wall effect; The high-voltage distribution circuit adopts a partitioning scheme to ensure uniform electric field strength of each anode wire.

4. The multi-layer based method according to claim 3 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The high voltage distribution circuit of the anode wire achieves gradient voltage reduction through a precision resistor chain circuit. Multiple high-resistance precision resistors are connected in series, and the total high voltage is applied to both ends of the resistor chain. The voltage is divided from the nodes to achieve gradient voltage reduction. The total current is stabilized at 75μA, and the resistance value is selected in steps according to the voltage difference range of 11.7V.

5. The multi-layer based method according to claim 1 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The readout electronics system adopts a two-tier architecture of "front-end signal processing - back-end digital readout", including: The front-end signal processing module adopts an ASIC-based readout scheme and is responsible for charge integration amplification and filtering shaping; The back-end digital readout module uses an FPGA as the core processing unit and integrates a high-precision ADC to realize two-dimensional position measurement and high-speed data transmission.

6. The multi-layer based method according to claim 5 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... In the aforementioned front-end signal processing module, a single front-end module integrates two 32-channel ASIC chips, with a charge sensitivity of 1mV / fC, enabling parallel processing of 64 channels.

7. The multi-layer based method according to claim 5 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... In the back-end digital readout module, the FPGA core processing unit integrates four high-precision ADCs. Each ADC can acquire 32 channels of signals, and the data transmission rate reaches 1Gb / s.

8. The multi-layer based method according to claim 1 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The multilayer 10 In B thin film structures, monolayer 10 The B4C thin film, with a thickness of 8 μm, was prepared by magnetron sputtering, with the addition of a gradient buffer layer and stress relief groove, and subsequent vacuum annealing to control the warpage to within 10 µm.

9. The multi-layer based method according to claim 1 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The detector employs a grazing incidence method, increasing the path of neutrons in the conversion layer and improving the interaction between neutrons and... 10 The probability of a B4C reaction is improved by optimizing the incident angle to increase detection efficiency and achieve sub-millimeter-level position resolution. Simultaneously, the neutron and conversion layer... 10 B4C also forms an angle θ, and 10 The path of the B4C conversion layer reaction, starting from the vertically incident s, extends to s / cosθ, where the neutron interacts with the conversion layer. 10 The B4C reaction pathway increases, allowing more neutrons to react with... 10 B4C reacts, thereby improving the detection efficiency of neutrons.

10. The multilayer-based system according to any one of claims 1 to 9 10 A grazing incidence high-resolution neutron detector with a thin film and fan-shaped architecture, characterized in that... The detector is suitable for multifunctional neutron reflectometers, enabling sub-millimeter-level position resolution in the normal direction of the sample surface and withstanding instantaneous count rates up to 100 kHz / mm².

Images