分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-06-12
摘要： While traditional gamma-gamma density (GGD) logging technology is widely utilized, its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density (NGD) logging technology. However, NGD measurements are influenced by both neutron and gamma radiation. In the logging environment, variations in formation composition indicate different elemental compositions, which affect neutron-gamma reaction cross-sections and gamma generation. Compared to traditional gamma sources such as Cs-137, these changes can significantly impact the generation and transport of neutron-induced inelastic gamma rays, posing challenges for accurate measurements. To address this, a novel method is proposed, the method incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation and therefore can achieve more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energy and spatial distributions in varied logging environments. The method avoids the complex correction of the neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents. showing thatthe absolute density errors are less than 0.02 g/cm3 in clean formations and demonstrating good accuracy. The research not only clarifies the NGD mechanism but also provides theoretical guidance for the application of NGD logging methods. Further research will be conducted regarding extreme environmental conditions and tool calibration.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-04-30
摘要： 钍基熔盐堆在运行过程中会排放85Kr和133Xe等放射性惰性气体（特征核素），准确监测尾气出口处各特征核素活度浓度对了解核反应堆与尾气处理系统的运行状况具有重要意义。β-γ符合法可显著降低本底且提高测量精度，能满足监测需求，因此设计了由PIPS和HPGe组成的符合监测装置。基于熔盐堆尾气中的核素活度浓度理论值，使用MCNP (Monte Carlo N Particle Transport Code) 设计了采样腔最佳尺寸，研究了探测器对β和γ探测效率的影响，并分析了监测装置的能谱及最小可探测活度浓度(Minimum Detectable Concentration，MDC)。结果表明：圆柱体型的采样腔最佳尺寸为高5.3cm，半径4.25cm，该监测装置具备核素识别能力且特征核素的MDC为10^3 -10^5 mBq/m3，达到设计需求。本文结果可为后续监测装置的加工与测试提供理论依据。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-04-16
摘要： 应用于超级陶璨装置（SuperTau-CharmFacility,STCF)的大型探测谱仪将为粒子物理前沿研究提供独特平台。其中，位于中心的圆柱阻性微井型内径迹探测器（InnerTracKer,ITK)由于具备低物质量、高计数率和高空间分辨能力，是低动量粒子径迹重建的关键组件之一。本文针对阻性微井型探测器的物理需求，开展高电荷分辨精度读出电子学的关键技术研究，并研制了一套1024路高集成度、高性能的读出电子学原理样机。该系统包含ASIC读出单元、前端电子学板和数据汇总板等电路，结构合理，易于扩展，并且经实验室仿真和板级测试，结果表明，系统功能符合预期，电荷分辨精度、积分非线性等指标满足需求，为下一步工程化提供了良好的技术支持。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-04-06
摘要： In-situ exploration of deep-sea seabed resources is a valuable research direction. Neutron activation-based in-situ exploration methods for seabed polymetallic nodules or crust resources are theoretically feasible because of the high content and high neutron capture cross-section of manganese in these nodules or crusts. However, to date, only a few relevant studies have been conducted. In this study, a prototype Deep-sea In-situ Neutron Activation Spectrometer (DINAS) was designed for resource exploration. Through an analysis of the principles of the spectrometer combined with Monte Carlo simulations of the physical principles and finite element simulations of deep-sea pressure, the structure and fundamental components of the spectrometer were determined. The inner core of the spectrometer comprised three components: a compact neutron generator for neutron production, gamma-ray detectors, and an electronics system. The gamma-ray detector array of the spectrometer consisted of LaBr3 and BGO scintillation crystals coupled with silicon photomultiplier (SiPM) arrays. The electronics system was divided into two modules to implement the SiPM readout and digital signal analysis along the modular design lines. The experimental activation of neutron beamlines at the China Spallation Neutron Source demonstrated the capability of the spectrometer detectors to detect activated gamma rays and showed that the spectrometer achieved an energy resolution of 2.8 % at 847 keV for the LaBr3 detector and 6.7 % at 2.113 MeV for the BGO detector. The laboratory model experiment tested the functionality of the spectrometer prototype, whereas the Geant4 simulation verified the reliability of the Monte Carlo method. The method and prototype proposed in this study proved feasible for the in-situ detection of polymetallic nodules or crusts in deep-sea environments
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-03-28
摘要： 电感耦合等离子体质谱（Inductively coupled plasma mass spectrometer, ICP-MS）是元素及同位素比分析的重要技术手段。其中飞行时间质谱（Time-of-flight Mass Spectrometer, TOF-MS)以其原理简单、灵敏度高、检测质量范围宽，并能一次获取全范围质量信息等特点在有机分子和生物医药检测领域获得广泛应用。本文针对钍基熔盐堆服役过程中铀及超铀元素的质量分析需求，实现了ICP离子源与TOF-MS相结合的物理设计并进行了仿真模拟。对离子通路的差分锥、偏转透镜、碰撞池、直流四极杆、单透镜、单反射飞行时间质量分析器等的电源参数进行优化，结合离子运动轨迹模拟验证了物理设计整体结构系统可行性。模拟结果显示：最优引导锥电压为-30 V；所设计偏转透镜系统最优偏转电压组合为-56 V与-530 V；碰撞池最优碰撞压强为1.6 Pa；直流四极杆与单透镜系统联用能将离子以4 eV左右的初动能接近水平状态引入TOF加速场；脉冲场电压为±200 V、加速电压为-1600 V、一级反射电压为48 V、二级反射电压为680 V时TOF-MS的质量分辨率M/ΔM大于4000。研究结果为后续的加工制造和搭建调试提供了重要的理论参考依据。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-02-25
Yin, Ziang
Zhang, Yaru
Kang, Zhe
Zhang, Xianggang
Liu, Jinbo
Liu, Kejin
Sun, Zhengyi
Jie, Wangqi
Zhao, Qinhua
Wang, Tao
摘要： Cadmium telluride (CdTe), which has a high average atomic number and a unique band structure, is a leadingmaterial for room-temperature X/γ-ray detectors. Resistivity and mobility are the two most importantproperties of detector-grade CdTe single crystals. However, despite decades of research, the fabrication ofhigh-resistivity and high-mobility CdTe single crystals faces persistent challenges, primarily because the stoichiometriccomposition cannot be well controlled owing to the high volatility of Cd under high-temperatureconditions. This volatility introduces Te inclusions and cadmium vacancies (VCd) into the as-grown CdTe ingot,which significantly degrades the device performance. In this study, we successfully obtained detector-gradeCdTe single crystals by simultaneously employing a Cd reservoir and chlorine (Cl) dopants via a vertical gradientfreeze (VGF) method. By installing a Cd reservoir, we can maintain the Cd pressure under the crystalgrowth conditions, thereby preventing the accumulation of Te in the CdTe ingot. Additionally, the existenceof the Cl dopant helps improve the CdTe resistivity by minimizing VCd density through the formation of anacceptor complex (ClTe-VCd)−1. The crystalline quality of the obtained CdTe(Cl) was evidenced by a reductionin large Te inclusions, high optical transmission (60%), and a sharp absorption edge (1.456 eV). Thepresence of substitutional Cl dopants, known as Cl+ Te, simultaneously supports the record high resistivity of1.5 × 1010 Ω · c meter and remarkable electron mobility of 1075±88 cm2 V−1 s−1 simultaneously, has beenconfirmed by photoluminescence spectroscopy. Moreover, using our crystals, we fabricated a planar detectorwith μτe of (1.11 ± 0.04) × 10−4 cm2/V, which performed with a decent radiation-detection feature. Thisstudy demonstrates that the vapor-pressure-controlled VGF method is a viable technical route for fabricatingdetector-grade CdTe crystals.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-02-10
摘要： 7 over multiple past decades,leading to a deeper understanding8of theintrinsicinteractions constituting thefieldsofParticle9 and Astroparticle Physics.Although important results have10 been acquired by indirect (ground-based) experiments over11theyears,there is an imminentneed toexplore highly ener-12 getic CR particles from GeV up to PeV and gamma-rays via13 direct observations, carried out by space-borne instruments.14The High Energy cosmic Radiation Detector (HERD）is15 a prominent space-borne instrument to be installed on-board16 the Chinese Space Station (CSS) around 2027 [3,4].The17 main scientific objectives of HERD include the search for sig-18 nals of dark matter annihilation products, precise cosmic ray19 spectrum and composition measurements up to the knee en-20 ergy, and high energy gamma-ray monitoring and survey [5-217].ThedatagatheredfromtheHERDdetectorscanprovide22valuableinformationfor developingradiation shielding tech-23nologies andmitigating therisksposedbycosmicradiation24 during long-duration space missions.The HERD project also25holds significantimplications for fundamentalphysicsre26search.Bystudyingthepropertiesofcosmicrays,researchers27 can probe the boundaries of particle physics.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-02-03
摘要： Neutron capture event imaging, as a novel imaging technique, has the potential to substantially enhance theresolution of the existing imaging system. This study provides a measurement method for neutron capture eventdistribution and multiple reconstruction methods for super-resolution imaging. This technology can reduce thepoint spread function of the imaging system through single neutron detection and event reconstruction, therebysignificantly improving the imaging resolution. In the experiment, a single neutron detection experiment wasconducted using the highly practical and efficient 6LiF – ZnS scintillation screen, relying on the cold neutronimaging device on the research reactor. In milliseconds of exposure time, a large number of weak light clustersand their distribution inside the scintillation screen were recorded frame by frame, completing single neutrondetection. In the calculation, several reconstruction algorithms were proposed. The location of the neutron cap#2;ture event was calculated by the several processing methods such as noise removal, filtering, spot segmentation,contour analysis, and local positioning. The proposed algorithm achieves higher imaging resolution and fasterreconstruction speed. Combining single neutron detection experiments and reconstruction calculations, singleneutron super-resolution imaging was finally achieved. The results show that the resolution of the 100 µm thick6LiF – ZnS scintillation screen can be improved from 125 microns to 40 microns. It indicates that the proposedsingle-neutron detection and calculation method is an effective technical route, which can significantly improvethe imaging resolution.
分类： 核科学技术 >> 核探测技术与核电子学 分类： 物理学 >> 核物理学 提交时间： 2024-12-17
Zhi-Xuan He
Pan-Jiao Shen
Jing-Yan Wang
Wen-Juan Bu
Zhou-Bo He
Zhi-Jie Li
Yuan-Sheng Yang
Xiao-Lei Chen
Chen-Gui Lu
Peng Ma
He-Run Yang
Li-Min Duan
Bi-Tao Hu
Xiang-Lun Wei
Yi Zhang
摘要： The semi-cylindrical Time Projection Chamber (scTPC) is designed to measure the angular distribution of the cross section of the intermediate-energy (3He,t) charge exchange reaction in inverse kinematics. The scTPC prototype has been constructed, consisting of a cathode, a field cage, a drift region, an amplification structure based on multi-layer thick gas electron multiplier (THGEM), and a readout plane with 886 zigzag-shaped pads. The gain uniformity of the THGEM and the drift velocity of electrons were calibrated. Then the track recognition based on the Hough transform was developed to reconstruct cosmic ray tracks and extract their position resolution. The position resolution of the secondary particle tracks from collisions between the heavy-ion beam and 3He target was also reported, with an x-resolution of 0.71 mm and a z-resolution of 0.73 mm. The scTPC is able to achieve sufficient energy resolution and spatial resolution to support the charge exchange reaction experiments in inverse kinematics.
分类： 核科学技术 >> 核探测技术与核电子学 分类： 物理学 >> 核物理学 提交时间： 2024-09-30
摘要： Nucleus is essentially composed of protons and neutrons, known commonly as nucleons. Interestingly, some of the nucleons may group together to show the collective behavior inside a nucleus. Such clustering effect has been known at the early stage of nuclear physics because of the observation and de
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-23
摘要： 普通放射性气溶胶监测仪不便携且难以快速部署，无法满足核应急响应的需求。本文的目的是开发一款坚固耐用、紧凑的便携式放射性气溶胶监测仪。该监测仪使用3D打印技术设计了独特的机壳气路结构，采用反符合探测器，选用雅特力超高效能微控制器利用双道能量甄别法进行信号采集，并基于Intel HD Graphics处理器使用α/β比值法、snip去本低法、二阶导数寻峰法对信号进行分析和处理，实现准确测量以及核素识别与分析。监测仪能够在手机客户端进行控制，可安装在无人巡检机器人和无人机上。测试结果表明，该监测仪α和β的探测下限为0.72Bq/m³和1.71 Bq/m³，稳定性能好，在装有准直部件的情况下保持较好的探测效率，在实时监测和应急响应方面具有显著优势，能够满足不同场景下的放射性气溶胶监测需求。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-21
摘要： 页岩是页岩气形成的物质基础，页岩岩性复杂、矿物成分变化大，依靠常规测井资料进行储层评价具有挑战性。FLex测井技术测量快中子与地层元素作用产生的γ射线能谱，通过解谱分析后获得地层的元素含量与矿物成分，从岩石化学成分角度为非常规储层的岩性评价开辟了一条新的道路。利用FLex元素测井岩石矿物解释模型对页岩岩相进行识别和划分，对页岩储层的脆性进行定量评价。研究表明，龙马溪组以硅质页岩为主，具有脆性矿物发育，黏土含量较低的特点，龙马溪组页岩可压性中等，具有一定的储层改造潜力，元素测井技术在页岩储层品质和可压性评价应用前景广泛。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-19
摘要： 摘要 目的 探讨剪波刀弹性成像（shear wave elastography，SWE）技术在评估肝硬化病情严重程度方面的应用价值。方法 选取2019年3月至2022年6月期间我院收治的130例肝硬化患者，采用Child-Pugh分级系统对病情进行评定，并利用SWE技术测量肝脏硬度和杨式模量值。同时，通过实验室检测患者的肝功能指标和血清纤维化指标。使用Pearson相关分析及其他统计学方法对收集到的数据进行分析，以确定SWE参数与肝硬化严重程度之间的相关性。结果 研究发现，不同Child-Pugh分级的患者肝脏硬度和杨式模量值存在显著差异（P<0.05），并且随着Child-Pugh分级的增加，这些指标呈现递增趋势。此外，肝脏硬度和SWE参数与肝硬化的程度、肝功能及肝纤维化程度均显示出较高的相关性，表明SWE技术在肝硬化病情评估中具有重要的参考价值。结论 剪波刀弹性成像参数与肝硬化的严重程度密切相关，为肝硬化的无创评估提供了一种有效的工具。本文的小样本研究结果提示SWE技术在肝硬化病情严重程度评估中具有潜在的临床应用价值。未来的研究将扩大样本量，并探索SWE技术在不同肝硬化病因中的诊断效能。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-12
摘要： 在核辐射探测中针对输出微电流的探测器，普遍采用美国ADI公司设计生产的ADA4530芯片搭建跨阻放大电路来进行微电流信号的测量。目前国内暂无ADA4530的国产替代，为解决该芯片的卡脖子问题，基于分离的场效应管和常规运算放大芯片搭建I-V跨阻转换电路，实现纯国产器件的弱电流放大电路设计。该电路的输出电压范围在0到10V之间，经过测试，当反馈电阻为100GΩ，输入电流为0.1~100pA时，其线性拟合优度为0.99998，相对偏差为0.235%，噪声峰峰值为0.057pA。当反馈电阻为10GΩ，输入电流为1pA时，在-10℃~80℃的温度变化范围内，其温漂小于0.042pA/℃。当反馈电阻为10GΩ，输入端悬空时，在室温6小时的稳定性测试中，输出漂移小于0.2662pA。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-09
摘要： 在核辐射探测中针对输出微电流的探测器，普遍采用美国ADI公司设计生产的ADA4530芯片搭建跨阻放大电路来进行微电流信号的测量。目前国内暂无ADA4530的国产替代，为解决该芯片的卡脖子问题，基于分离的场效应管和常规运算放大芯片搭建I-V跨阻转换电路，实现纯国产器件的弱电流放大电路设计。该电路的输出电压范围在0到10V之间，经过测试，当反馈电阻为100GΩ，输入电流为0.1~100pA时，其线性拟合优度为0.99998，相对偏差为0.235%，噪声峰峰值为0.057pA。当反馈电阻为10GΩ，输入电流为1pA时，在-10℃~80℃的温度变化范围内，其温漂小于0.042pA/℃。当反馈电阻为10GΩ，输入端悬空时，在室温6小时的稳定性测试中，输出漂移小于0.2662pA。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-04
摘要： 放射性物质的准确定位对于寻找“孤儿源”、核设施去污和退役、辐射防护最优化等至关重要。硅光电倍增器（Silicon Photomultiplier，SiPM）已经广泛应用于闪烁体探测系统。为实现低成本大视野高分辨探测系统，设计验证了将电阻网络、前置放大电路和ASIC模块相结合的混合模式读出电路。为了提高定位的鲁棒性，先用单根硅酸钇镥闪烁晶体（LYSO）标定了定位阈值，进一步更换掺铈钆铝镓石榴石晶体（Cerium-doped Gadolinium Aluminum Gallium Garnet, GAGG(Ce)）阵列，用241Am点源检验标定实验的结果，测试结果显示：读出电路RMS噪声约为3mV，很好地保留了信号的能量和位置信息，平均能量分辨率约为12.13%。设计的混合模式读出电路将64路SiPM信号简化为4路，探测器输出信号通道数减少16倍，单个ASIC模块能同时读出1024个SiPM单元，能大大降低大面积SiPM阵列读出的成本。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-07-04
摘要： Cosmic-ray muons are highly penetrating background-radiation particles found in natural environments. In this study, we develop and test a plastic scintillator muon detector based on machine-learning algorithms. The detector underwent muon position-resolution tests at the Institute of Modern Physics in Lanzhou using a mul tiwire drift chamber (MWDC) experimental platform. In the simulation, the same structural and performance parameters were maintained to ensure the reliability of the simulation results. The Gaussian process regression (GPR) algorithm was used as the position-reconstruction algorithm owing to its optimal performance. The re sults of the Time Difference of Arrival algorithm were incorporated as one of the features of the GPR model to reconstruct the muon hit positions. The accuracy of the position reconstruction was evaluated by comparing the experimental results with Geant4 simulation results. In the simulation, large-area plastic scintillator detectors achieved a position resolution better than 20 mm. In the experimental-platform tests, the position resolutions of the test detectors were 27.9 mm. We also analyzed factors affecting the position resolution, including the crit ical angle of the total internal reflection of the photomultiplier tubes and distribution of muons in the MWDC. Simulations were performed to image both large objects and objects with different atomic numbers. The results showed that the system could image high- and low-Z materials in the constructed model and distinguish objects with significant density differences. This study demonstrates the feasibility of the proposed system, thereby providing a new detector system for muon-imaging applications.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-06-28
摘要： 放射性测量广泛存在于核技术应用的各个领域，测量不确定度、置信区间、探测限等是放射性测量的重要参数，其计算结果直接影响相关决策。利用偏导数方法和蒙特卡洛方法研究α粒子活度浓度测量中的重要参数：首先对测量结果不确定度来源进行分析，再利用偏导数和MC（Monte Carlo）方法计算α粒子活度浓度不确定度、置信区间、判定阈和探测限等。结果表明：当输入量不确定度高于10%时，两种计算方法所得置信区间与不确定度结果相对偏差大于15%；输入量相对不确定度较小时，探测限约判定阈的2倍。偏导数方法应用较广，但未考虑输入量的概率分布形式，不适用于复杂和特殊输入量的模型，据此可借助蒙特卡罗方法得到更加可靠的计算结果，这两种方法可以互补应用。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-06-28
摘要： 使用传统的蒙特卡罗方法计算CdZnTe探测器探测效率时存在效率损失。为了将无源效率刻度技术应用于CdZnTe探测器，提出了基于理想模型（仅考虑光子与探测器晶体和结构材料相互作用过程）的CdZnTe探测效率计算方法。使用152Eu标准源样品验证了计算方法的可靠性，结果表明，计算结果与参考值的偏差不大于5%。该方法不需要考虑CdZnTe晶体内载流子不完全收集的复杂过程就可以得到可靠的效率计算结果，可操作性强。
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2024-06-25
摘要： X-ray detectors show potential applications in medical imaging, materials science, and nuclear energy. To achieve high detection efficiency and spatial resolution, many conventional semiconductor materials, such as amorphous selenium, cadmium telluride zinc, and perovskites have been utilized in direct conversion X-ray detectors. However, these semiconductor materials are susceptible to temperature-induced performance degradation, crystallization, delamination, uneven lattice growth, radiation damage, and high dark current. This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor (CMOS) pixel array, specifically the Topmetal $ textrm{ uppercase expandafter{ romannumeral2}}^{-}$ chip, to fabricate a direct conversion X-ray detector. The fluorinated liquid FC40 (molecular formula: $ ce{C^{21}F^{48}N^2}$) is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity. It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption. This addresses the limitations inherent in conventional semiconductor-based detectors. In this study, simple X-ray detector imaging tests were conducted, demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector. A spatial resolution of SI{4.0}{lp/mm} was measured using a striped line par card, and a relatively clear image of a cockroach was displayed in the digital radiography imaging results. Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips. Owing to the absence of issues related to chip-material coupling, a high spatial resolution could be achieved by reducing the chip pixel size. This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.
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