高速数字化三维集成式CCD-CMOS图像传感器

为了解决CCD与CMOS工艺兼容性低、互连集成制作难度大,以及芯片间接口匹配和高性能兼备等问题,对CCD器件拓扑结构与像元、CMOS读出电路、三维异质互连集成及高密度引脚封装等技术进行研究,提出了一种1024×256阵列规模的集成式CCD-CMOS图像传感器。该器件实现了CCD信号的高精度数字化处理、高速输出及多芯粒的技术融合,填补了国内CCDCMOS三维集成技术空白。测试结果表明:集成CCD-CMOS器件的光响应和成像功能正常,双边成像效果良好,图像无黑条和坏列,互连连通率(99.9%)满足三维集成要求,实现了集成式探测器件的大满阱高灵敏度成像(满阱电子数达165.28ke^(-)、峰值量子效率达86.1%)、高精度数字化(12bit)和高速输出(行频率达100.85kHz),满足集成化、数字化、小型化的多光谱探测成像系统要求。

Test system of the front-end readout for an application-specific integrated circuit for the water Cherenkov detector array at the large high-altitude air shower observatory

The water Cherenkov detector array(WCDA) is an important part of the large high-altitude air shower observatory(LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit(ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range[1-4000photoelectrons(P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30%root mean square(RMS) at 1 P.E.and 3%RMS at 4000 P.E.,which are beyond the application requirements.

Compact 16-channel integrated charge-sensitive preamplifier module for silicon strip detectors

In this study,a compact 16-channel integrated charge-sensitive preamplifier named the smart preamplifier(SPA)was developed to support the large-scale detector array used in modern nuclear physics experiments.Two types of SPA,namely SPA02 and SPA03(with external field effect transistor),have been manufactured to match silicon detectors with small and large capacitances,respectively.The characteristics of the SPA include fast response of typically less than 6 ns for pulse rising time and low equivalent noise of 1.5 keV at zero input capacitance.The energy sensitivity and pulse decay time can be easily adjusted by changing the feedback capacitance Cfand resistance Rfin various applications.A good energy resolution of 24.4 keV for 5.803-MeV alpha particles from 244 Cm was achieved using a small-sized Si-PIN detector;for the silicon strip detectors in the test with the alpha source,a typical energy resolution of 0.6–0.8%was achieved.The integrated SPA has been employed in several experiments of silicon strip detectors with hundreds of channels,and a good performance has been realized.

A versatile 16-channel front-end integrated circuit for semiconductor radiation detectors

A CMOS front-end integrated circuit consisting of 16 identical analog channels is proposed for semiconductor radiation detectors. Each of the 16 channels has a low noise charge sensitive amplifier, a pulse shaper, a peak detect and hold circuit and a discriminator, while analog voltage and channel address are routed off the chip. It can accommodate both electron and hole collection with selectable gain and peaking time. Sequential and sparse readout, combining with self-trigger and external trigger, makes four readout modes. The circuit is implemented in a 0.35 μm DP4M (double-poly-quad-metal) CMOS technology with an area of 2.5×1.54 mm2 and power dissipation of 60 mW. A single channel chip is tested with Verigy 93000. The gain is adjustable from 13 to 130 mV·fC–1 while the peaking time varies between 0.7 and 1.6 μs. The linearity is more than 99% and the equivalent noise charge is about 600e.

Design of high-performance energy integrator detector for wideband radar

Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance deterioration if the detection window is not selected properly. In this paper, an EI detector for the distributed targets in the Gaussian environment is proposed.First, at the stage of preparatory work, the target models are proposed, then, the problem formulation is introduced. Subsequently,in the aspect of optimizing the method of detection window search and the method of threshold setting, the detailed design stages of the proposed detector are provided. Furthermore, theoretical analyses show that the proposed detector is easy to hardware implementation, and it does not need the prior knowledge about the spatial distribution of the target scattering centers in practical radar detection application. Finally, the performance assessment conducted by Monte Carlo simulations verifies that the proposed detector outperforms the conventional detectors.

The analysis of the integral gated mode single photon detector

This paper critically analyses and simulates the circuit configuration of the integral gated mode single photon detector which is proposed for eliminating the transient spikes problem of conventional gated mode single photon detector. The relationship between the values of the circuit elements and the effect of transient spikes cancellation has been obtained. With particular emphasis, the bias voltage of the avalanche photodiode and the output signal voltage of the integrator have been calculated. The obtained analysis results indicate that the output signal voltage of the integrator only relates to the total quantity of electricity of the avalanche charges by choosing the correct values of the circuit elements and integral time interval. These results can be used to optimize the performance of single photon detectors and provide guides for the design of single photon detectors.

PERFORMANCE COMPARISON OF A LINEARLY COMBINED ORDERED-STATISTIC DETECTORS UNDER POSTDETECTION INTEGRATION AND NONHOMOGENEOUS SITUATIONS

Several Constant False Alarm Rate (CFAR) architectures, where radar systems often employ them to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain an approximately constant rate of false alarm, have been recently proposed to estimate the unknown noise power level. Since the Ordered-Statistics (OS) based algorithm has some advantages over the Cell-Averaging (CA) technique, we are concerned here with this type of CFAR detectors. The Linearly Com- bined Ordered-Statistic (LCOS) processor, which sets threshold by processing a weighted ordered range sam- ples within finite moving window, may actually perform somewhat better than the conventional OS detector. Our objective in this paper is to analyze the LCOS processor along with the conventional OS scheme for the case where the radar receiver incorporates a postdetection integrator amongst its contents and where the oper- ating environments contain a number of secondary interfering targets along with the primary target of concern and the two target types fluctuate in accordance with the Swerling II fluctuation model and to compare their performances under various operating conditions.

GPS Vector Tracking Receivers with Rate Detector for Integrity Monitoring

In this paper,the integrity monitoring algorithm based on a Kalman filter(KF)based rate detector is employed in the vector tracking loop(VTL)of the Global Positioning System(GPS)receiver.In the VTL approach,the extended Kalman filter(EKF)simultaneously tracks the received signals and estimates the receiver’s position,velocity,etc.In contrast to the scalar tracking loop(STL)that uses the independent parallel tracking loop approach,the VTL technique uses the correlation of each satellite signal and user dynamics and thus reduces the risk of loss lock of signals.Although the VTL scheme provides several important advantages,the failure of tracking in one channel may affect the entire system and lead to loss of lock on all satellites.The integrity monitoring algorithm can be adopted for robustness enhancement.In general,the standard integrity monitoring algorithm can timely detect the step type erroneous signals.However,in the presence of ramp type slowly growing erroneous signals,detection of such type of error takes much more time since the error cannot be detected until the cumulative exceeds the specified threshold.The integrity monitoring based on the rate detector possesses good potential for resolving such problem.The test statistic based on the pseudorange residual in association with the EKF is applied for determination of whether the test statistic exceeds the allowable threshold values.The fault detection and exclusion(FDE)mechanism can then be employed to exclude the hazardous erroneous signals for the abnormal satellites to assure normal operation of GPS receivers.Feasibility of the integrity monitoring algorithm based on the EKF based rate detector will be demonstrated.Performance assessment and evaluation will be presented.

安徽省县域城乡融合耦合协调度时空演化及机制研究

县域是城乡融合与乡村振兴的重要载体,耦合协调是透视地区协调发展水平的重要标志。文章首先构建了城乡融合评价指标体系,运用耦合协调度模型、空间自相关和趋势面分析方法,定量测度了安徽省2010—2020年的城乡融合耦合度及耦合协调度的时空演变过程,并使用地理探测器模型来探索影响城乡融合的因素及影响程度。结果表明:首先,2010—2020年,城乡融合的耦合度和耦合协调度呈先下降后波动上升的趋势,但整体波动幅度较小,各县区耦合度的变化出现“聚集—分散—聚集”的“东移南迁”现象,耦合协调度轻度失调的区县呈逐渐减少的趋势,出现了地域低值锁定现象,主要分布在皖北地带。其次,分区域来看,皖北、皖中、皖南的城乡融合耦合协调以2015年为转折点,先小幅上升后又持续升高。其中,皖南和皖北区域协调差异趋于直线式减弱;而皖中区域差异呈现波动发展。整体来看,城乡融合耦合协调呈现出“北低南高—西低东高”的空间格局。随着时间的推移,形成了淮河以北冷点区和长江以南热点区阶梯状新格局。最后,PM2.5浓度、人均GDP、流域、农业机械总动力、农业产值占比、森林覆盖率、农村人均用电量、城镇化率、城乡人均可支配收入比是影响安徽省城乡融合耦合协调发展的主要因素。

基于数值积分法的无源效率刻度方案研究

无源效率刻度技术一直是核分析领域研究的热点,但现行无源效率刻度技术需依据指定探测器进行订制。基于伽马射线指数衰减规律推导了圆柱体探测器周边任意位置点源探测效率的数值积分公式。依据探测器与待测物几何结构的轴对称性和伽马场叠加原理,构建了实验室常用几何结构体源的探测效率计算方案。在笔记本电脑(CPU:i5-8250U@1.60 GHz;RAM:8.0 GB)上应用上述方法计算HPGe圆柱体探测器对马林杯水体和NaI圆柱体探测器对圆柱体土壤内多种能量特征伽马射线的探测效率,发现探测效率计算值与实验值之间相对偏差为-4.9%~3.9%,且计算时长最大为35.78秒,证实本方法能准确、快速地实现圆柱体探测器的无源效率刻度。且本文推荐方法在探测器尺寸变化的情况下仅需修改相应参数,具有很强的通用性。

量子级联技术研究进展:从光源到探测

量子级联技术基于多量子阱或超晶格结构中的子带跃迁和共振隧穿理论,既可以产生光源,又可以探测光信号,是量子级联激光器(QCL)和量子级联探测器(QCD)的理论基石,在检测、遥感、通信、雷达等领域具有广泛的应用前景。经过最近三十年的研究,量子级联技术在基础研究、产品性能以及应用系统研发和场景试验方面都取得了重大进展。本文首先简要介绍了量子级联技术的原理和发展历史,随后阐述了量子级联器件子带能级结构和电子输运动力学计算思路,接着重点综述了量子级联技术的研究进展,包括中远红外高功率QCL、中远红外宽调谐QCL、太赫兹QCL、高性能QCD,以及QCL和QCD的单芯片光子集成方面的内容,最后介绍了QCL和QCD的产品与应用情况。

Spatiotemporal variations of ecosystem services and driving factors in the Tianchi Bogda Peak Natural Reserve of Xinjiang,China

Nature reserves play a significant role in providing ecosystem services and are key sites for biodiversity conservation.The Tianchi Bogda Peak Natural Reserve(TBPNR),located in Xinjiang Uygur Autonomous Region,China,is an important ecological barrier area in the temperate arid zone.The evaluation of its important ecosystem services is of great significance to improve the management level and ecological protection efficiency of the reserve.In the present study,we assessed the spatiotemporal variations of four ecosystem services(including net primary productivity(NPP),water yield,soil conservation,and habitat quality)in the TBPNR from 2000 to 2020 based on the environmental and social data using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.In addition,the coldspot and hotspot areas of ecosystem services were identified by hotspot analysis,and the trade-off and synergistic relationships between ecosystem services were analyzed using factor analysis in a geographic detector.During the study period,NPP and soil conservation values in the reserve increased by 48.20%and 25.56%,respectively;conversely,water yield decreased by 16.56%,and there was no significant change in habitat quality.Spatially,both NPP and habitat quality values were higher in the northern part and lower in the southern part,whereas water yield showed an opposite trend.Correlation analysis revealed that NPP showed a synergistic relationship with habitat quality and soil conservation,and exhibited a trade-off relationship with water yield.Water yield and habitat quality also had a trade-off relationship.NPP and habitat quality were affected by annual average temperature and Normalized Difference Vegetation Index(NDVI),respectively,while water yield and soil conservation were more affected by digital elevation model(DEM).Therefore,attention should be paid to the spatial distribution and dynamics of trade-off and synergistic relationships between ecosystem services in future ecological management.The findings of the present study provide a reference that could facilitate the sustainable utilization of ecosystem services in the typical fragile areas of Northwest China.

Response of ecosystem carbon storage to land use change from 1985 to 2050 in the Ningxia Section of Yellow River Basin,China

Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage(ECS),particularly in ecologically sensitive areas with arid and semi-arid climate.In this study,we calculated the ECS in the Ningxia Section of Yellow River Basin,China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model based on land use data.We further predicted the spatial distribution of ECS in 2050 under four land use scenarios:natural development scenario(NDS),ecological protection scenario(EPS),cultivated land protection scenario(CPS),and urban development scenario(UDS)using the patch-generating land use simulation(PLUS)model,and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector(Geodetector).Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×10^(6) t in 2010,followed by a decreasing trend to 2050.The spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area,and low values in the western and northern parts.Between 1985 and 2020,land use changes occurred mainly through the expansion of cultivated land,woodland,and construction land at the expense of unused land.The total ECS in 2050 under different land use scenarios(ranked as EPS>CPS>NDS>UDS)would be lower than that in 2020.Nighttime light was the largest contributor to the spatial differentiation of ECS,with soil type and annual mean temperature being the major natural driving factors.Findings of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.

用于DSA介入诊疗的辐射精细测量设备研制

DSA介入诊疗需要医生在X射线引导下进行手术,长时间的手术可能造成医生过量照射。有必要研制一款小型的实时辐射测量仪,对医生手术过程中重点关注部位所受的辐照情况进行精准测量,发现辐射屏蔽弱项,制定合理的屏蔽方案。基于芯片技术研制一款小型化、低功耗、实时测量的辐射剂量测量模块,使用MCNP模拟程序,计算在不同补偿片厚度下探测器的能量响应曲线,得出补偿片的最优厚度。并对该测量模块的各项性能指标如重复性、剂量线性、能量响应、耐辐照剂量进行测试验证。结果表明,测量模块的重量小于15 g,体积小于15 mm×10 mm×5 mm,剂量率测量上限可拓展至1 Sv/h,能量响应在10~250 keV范围内好于±30%,耐辐照剂量上限好于100 Gy。本研究解决了实时辐射测量设备小型化的难题,可为DSA诊疗的医生提供辐射测量方法,实现手部X射线照射剂量的实时测量,通过术后数据回溯,进行辐照风险分析,为屏蔽方案优化提供技术和数据参考。

基于加速度传感器的电梯多参数检测仪设计

轿厢运动参数、振动舒适度、制动性能参数、异常振动频率、倾斜角等多个参数的现场检测对确保电梯安全稳定运行具有重要意义。传统模拟量输出型加速度传感器由于体积大、集成度低,较难实现电梯的多功能、多参数检测需求。基于微机电系统三轴加速度传感器和高性能单片机,开发了电梯多参数检测仪。该检测仪包括三轴加速度无线测量模块和智能终端应用程序。现场应用表明,该检测仪可实现电梯速度及加速度测量、轿厢振动舒适度测量、自动扶梯梯级和扶手带振动舒适度测量、电梯制动参数测量、异常振动源追溯等功能,可广泛应用于电梯安装、维保、检验、抽查、事故调查等测试场合。基于微机电系统加速度传感器的仪器设计思路可为类似机电类设备的安全检测提供有效参考。

PERFORMANCE EVALUATION OF THE DOUBLE-THRESHOLD CFAR DETECTOR IN MULTIPLE-TARGET SITUATIONS

In radar systems of automatic detection, an estimate of background clutter power is used to set the detection threshold. An interference saturated environment is frequently encountered in these systems (multiple target situations). Therefore, the detection of signals in such an environment becomes one of the most important problems to be solved. The double-threshold algorithm is one of the more interesting detectors used in these situations. While the first threshold operation ensures that the calculation of the detection (second) threshold is based on a set of samples which is free of strong interferers and is therefore much more representative of the noise level, the second threshold is used to declare the presence or the absence of the radar target. The object of the present paper is to analyze the performance of such type of CFAR schemes when the radar receiver contains a noncoherent integrator amongst its basic elements. It is found that the processor detectabil ity loss is very low and the performance degradation, caused by interferers is quite small even if the number of outlying targets is large, given that the first threshold is properly chosen.

EXACT ANALYSIS OF OS MODIFIED VERSIONS WITH NONCOHERENT INTEGRATION

This paper deals with the exact detection analysis of the Ordered-Statistic(OS) processor along with OS Greatest Of(OSGO) and OS Smallest Of(OSSO) modified versions, for M postdetection integrated pulses when the operating environment is nonhomogeneous. Analytical results are presented in multiple-target case as well as in regions of clutter power transitions. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the SWII target fluctuation model. As the number of noncoherently integrated pulses increases,lower threshold values and consequently better detection performances are obtained in both homogeneous and multiple target background models. However, the false alarm rate performance of OSSO-CFAR(Constant False Alarm Rate) scheme at clutter edges is worsen with increasing the postdetection integrated pulses. As predicted, the OSGO-CFAR detector accommodates the presence of spurious targets in the reference window, given that their number is within its allowable range in each local window, and controls the rate of false alarm when the contents of the reference cells have clutter boundaries.

ANALYSIS OF CELL-AVERAGING BASED DETECTORS FOR χ^2 FLUCTUATING TARGETS IN MULTITARGET ENVIRONMENTS

The χ 2family of signal fluctuation distributions represents the main fluctuation models which most radar targets follow it in their reflections. This family can be categorized as fluctuation distribution with two degrees of freedom and those with four degrees of freedom. The first category represents an important class of fluctuation models which when illuminated by a coherent pulse train, return a train of fully correlated pulses (Swerling I model) or fully decorrelated pulses (Swerling II model). The detection of this type of fluctuating targets is therefore of great importance. This paper is devoted to the analysis of Cell-Averaging (CA) based de-tectors for the case where the radar receiver noncoherently integrates M square-law detected pulses and the sig-nal fluctuation obeys χ 2statistics with two degrees of freedom. These detectors include the Mean-Of (MO), the Greatest-Of (GO) and the Smallest-Of (SO) schemes. In these processors, the estimation of the noise power levels from the leading and the trailing reference windows is based on the CA technique. Exact formulas for the detection probabilities are derived, in the absence as well as in the presence of spurious targets. The pri-mary and the secondary interfering targets are assumed to be fluctuating in accordance with the χ 2fluctuation model with two degrees of freedom (SWI & SWII). The numerical results show that the MO version has the best homogeneous performance, the SO scheme has the best multiple-target performance, while the GO proce-dure does not offer any merits, neither in the absence nor in the presence of outlying targets.

X-ray photon counting detectors for preclinical and clinical applications

Photon counting detectors(PCDs) have attained w ide use in X-ray imaging for various preclinical and clinical applications in the past decade. This paper briefly review s the preclinical and clinical applications of PCDs based X-ray imaging systems.Starting with an introduction of X-ray single photon detection mechanism,the brief review first describes tw o major advantages of utilizing PCDs: photon energy resolving capability and electronic noise elimination. Compared to energy integrating detectors(EIDs),the aforementioned advantages make PCDs more favorable in X-ray imaging with profound benefits such as enhanced tissue contrast,decreased image noise,increased signal to noise ratio,decreased radiation dose to the small animals and patients,and more accurate material decomposition. The utilizations of PCDs in X-ray projection radiography and computed tomography(CT)including micro-CT,dedicated breast CT,K-edge CT,and clinical CT are then review ed for the imaging applications ranging from phantoms to small animals and humans. In addition,optimization methods aiming to improve the imaging performance using PCDs are briefly review ed. PCDs are not flaw less though,and their limitations are also discussed in this review. Nevertheless,PCDs may continuously contribute to the advancement of X-ray imaging techniques in future preclinical and clinical applications.