新型高温超导红外探测器速度快灵敏度高

美国劳伦斯伯克利实验窒的研究人员,最近研制成功高温超导红外探测器。这种用高温超导材料制成的红外探测器,可探测微弱的红外光,它是将光信号转换成热信号来进行探测的。劳伦斯伯克利实验室研制的这种高温超导红外探测器的性能大大优于其他单位研制的高温超导红外探测器。它最适     

高T_C超导红外探测器的现状与前景

本文介绍了国内外高温(高于77K)超导红外探测器的进展情况,叙述了各种类型高温超导红外探测器的机理和结构形式,评述了今后的发展趋势及应用前景。     

高温超导红外探测器综述

概述了高温超导红外探测器的优势,介绍了其探测机理及目前国内外探测器的发展方向,并简术字我们的研究近况。     

8元线列高温超导薄膜红外探测器及其热成象系统的研制

本文综述了超导红外探测器与传统的半导体红外探测器相比所具有的潜在优势，介绍了国内外在超导红外探测器研究方面的进展，报道了８无线列ＹＢＣＯ高温超导薄膜红外探测器的制备工艺与研究结果，以及采用该探测器研制出的超导红外热成象系统，从而证实了采用超导红外热成象技术的应用前景及存在的问题。     

高Tc超导红外探测器的发展

较全面地阐述了国内外高T_C(>77K)超导红外探测器的发展水平,它包括红外探测机理,探测器的结构和工艺以及今后的发展趋势,特别评估了高温超导红外焦平面的潜在应用价值。     

高温超导红外探测器对1—1000μm波段的光谱响应

采用ＹＢａＣｕＯ高温超导薄膜，制成芯片为蛇形的Ｔｃ超导Ｂｏｌｏｍｅｔｅｒ，对１￣１０００μｍ波段的光谱响应进行了测量，本文报道了实际测量结果，表明高温超导红外探测器在红外－毫米波段有应用前景。     

77K超导红外探测器在北京国际高温超导会议上参展

昆明物理研究所1989年8月用本所研制的Y-Ba-Cu-O高温超导薄膜试制的两支在77K使用的超导红外探测器,在1989年9月5日—8日的北京国际高温超导会议上展出。自1987年高温超导材料出现以来,在我国,77K超导红外探测器是继77K Squid之后出现的又一个初期开发应用器件。器件的核心元件——微桥或蛇形芯片安装在带KRS-5窗口     

高温超导晶界结型红外探测器工作原理

提出了高温超导晶界结型红外探测器在液氮温区可能同时存在测辐射热和光致非平衡两种效应的工作原理,给出了两种效应的响应率计算式,并在实验上研制了性能指标较高的YBa_2Cu_3O_(7-x)红外探测器。     

高温超导晶界结型经外探测器工作原理

提出了高温超导晶界结型红外探测器在液氮温区可能同时存在测辐射热和光致非平衡两种效应的工作原理，给出了两种效应的响应率计算式，并在实验上研制了性能指标较高的YBa2Cu3O7-x红外探测器。     

线列混合型石英微透镜/红外探测器阵列的研究

阐述了利用离子束刻蚀技术制作线列长方状拱面石英微透镜阵列的工艺方法，对所制微光学元件的光学性能进行了测试和讨论，所制成的石英微透镜阵列器件在线列ＹＢａ２Ｃｕ３Ｏ７－δ高Ｔｃ超导薄膜红外探测器上得到了应用。实验结果表明，混合型的石英微透镜／红外探测器结构显著改善了线列ＹＢＣＯ高温超导薄膜红外探测器的光响应特性。     

The measurement of frequency dependance of surface resistance in high Tc superconductor

We have measured the penetration depth and conductivity of high Tc superconductor at liquid nitrogen temperature by using microwave transmission method. After that we obtain the frequency dependance of surface resistance in high Tc superconductor. Experimental results show that the surface resistance of high Tc superconductor is proportional to the square of frequency as theoretical prediction. The advantage of microwave transmission method is broadband and easy to use.     

The measurement of penetration depth and surface resistance of bulk YBCO superconductor by using microstrip resonator method

We have measured the resonance curves of a high Tc superconducting microstrip resonator at both room temperature and liquid nitrogen temperature, and done same thing to a copper microstrip resonator with the same width and length as high Tc superconducting microstrip resonator. These four curves have been compared with each other. After that we obtained the penetration depth and surface resistance of high Tc superconductor at liquid nitrogen temperature. The microstrip resonator method has the advantage of simple. The results agree with theoretical prediction and other papers quite well.     

Fast SPECT simulation including object shape dependent scatter

A fast simulator of SPECT projection data taking into account attenuation, distance dependent detector response, and scatter has been developed, based on an analytical point spread function model. The parameters of the scatter response are obtained from a single line source measurement with a triangular phantom. The simulator is able to include effects of object curvature on the scatter response to a high accuracy. The simulator has been evaluated for homogeneous media by measurements of (99m)Tc point sources placed at different locations in a water-filled cylinder at energy windows of 15% and 20%. The asymmetrical shapes of measured projections of point sources are In excellent agreement with simulations for both energy windows. Scatter-to-primary ratio (SPR) calculations of point sources at different positions in a cylindrical phantom differ not more than a few percent from measurements. The simulator uses just a few megabytes of memory for storing the tables representing the forward model; furthermore, simulation of 60 SPECT projections from a three-dimensional digital brain phantom with 6-mm cubic voxels takes only ten minutes on a standard workstation. Therefore, the simulator could serve as a projector in iterative true 3-D SPECT reconstruction.     

高温超导引线的传输特性

从电磁学理论入手,给出了引线的基本理论。对高温超导引线的传输特性进行了分析,并对金属引线和导引线的性能进行了比较。得到以下结论：（１）在超导能隙频率下,金属引线的衰减系数比高温超导引线大几个数量级;（２）金属引线的相速与信号频率无关,易出现信号发散,而超导引线在低于能隙率的情况下,相速与频率无关,信号不发散;（３）金属引线对脉冲信号的延迟时间比超导引线高。     

高温超导材料研究近况

近两年高温超导又取得了巨大的进展，特别是在：（１）新的更高温度超导体系的探索，这包括进一步提高Ｔｃ值和合成新结构、新类型的超导材料；（２）材料的应用基础研究，主要指超导块材、线材、带材、膜材料的制备和改进，包括ＳＱＵＩＤ、Ｊｏｓｅｐｈｓｏｎ结和微波无源器件；（３）对高温超导现象的解释和机理的研究方面尤为显著。本文重点介绍过去一年高温超导在材料研究方面的主要进展。     

单光子探测器研究现状与发展

单光子探测器的研制是量子光学和量子信息领域的一个重要研究课题。单光子探测器突破了传统探测器只针对振幅进行采样的局限,同时对光波或者光子的偏振、波矢、位相等特性进行探测,具有可保持测量信号完整性、理论量子效率高、工作电压低、探测灵敏度高等优点,同时具有室温单光子探测的潜力。为了深入了解单光子探测器的研究现状和发展前景,本文介绍了单光子探测器的工作机理,总结对比了光电倍增管、雪崩光电二极管等传统单光子探测器以及基于新型二维材料的雪崩光电二极管、超导纳米线单光子探测器等新型单光子光电探测器的优势与不足,并对其发展前景进行了展望。此外还介绍了单光子探测器在量子通信、激光测距和成像等领域的应用。     

SPRINT II: a second generation single photon ring tomograph

SPRINT II is a stationary detector ring tomograph designed for brain imaging. Eleven two-dimensional sodium iodide camera modules that use maximum-likelihood position logic are arranged in a 50-cm-diameter ring with a scintillator packing fraction of 96%. A 34-cm-diameter rotating lead aperture ring containing either 10 or 12 slits is used for in-plane collimation, while the z-axis collimator is constructed of parallel lead foil rings. The field of view is 22 cm in diameter by 12 cm long. Sensitivity is 10 count/s/muCi for an on-axis (99m)Tc point source and 8500 count/s/muCi/cm(3) for 19.8-cm-diameter by 6.2-cm-long cylindrical source. Longitudinal resolution is 10 mm FWHM, and in-plane resolution varies from 8 mm FWHM on-axis to 5 mm FWHM at a radius of 9 cm. Performance results are presented.     

Analysis of anisotropy of high Tc superconducting oxides using multi-CuO2-layer structure model

The anisotropy of high Tc superconducting oxides such as Bi₂Sr₂Ca₁Cu₂O₈ is analized by use of the multi-CuO₂-layer structure model. It is found that the anisotropy decreases when Tc increases. Under high pressure, the anisotropy also decreases.     

高Tc超导薄膜的实用化问题

本文叙述了高Te超导薄膜的主要进展,并讨论了它的实用化问题     

Design Considerations for Positron Emission Tomography

The surge of interest in medical research with positron-emitting nuclides has been accompanied by improvements in the design of positron emission tomographs (scanners). Bismuth germanate has emerged as the scintillation material of choice for high resolution scanners, as its detection efficiency with small crystals is higher than that of NaI. Other detector materials, such as CsF, may be useful when timing accuracy is of great importance, as in high count rate studies or time-of-flight measurements. Circular detector arrays are now generally preferred because they provide the best sensitivity and uniformity of coverage. Multiple rings are used to increase the axial coverage. Other design parameters, such as detector and collimator dimensions, are surveyed and their effect on scanner performance is discussed.