非制冷红外焦平面列阵进展

叙述了室温下工作的，或在使用温差电制冷条件下近室温工作的长波红外焦平面列阵的最新进展。主要介绍两种类型的器件：一类是利用铁电材料的热释电效应以及介电常数的温度变化制作的探测器，常用材料是钛酸锶钡和钽钪酸铅铁电陶瓷；另一类是利用电阻温度变化的测辐射热器，材料为氧化钒。用这两类室温工作的红外焦平面列阵制作的热像仪的噪声等效温差已达到０．１℃。装有这种热瞄具的步枪已经历过实战考验。热瞄具还可用于夜间车辆     

星载高灵敏度太赫兹遥感接收技术

从工程实现的角度,提出了针对星载太赫兹遥感的热电子测辐射热(HEB)探测技术,给出其实现方式。针对星载杜瓦、超导结材料的选取、宽频带天线的研制和HEB接收机的研制进行了分析,讨论了其关键难点和实现途径,对国外星载应用进行了阐述。总结了HEB探测的特点,从关键技术入手,得到了一种用于星载遥感的超导HEB探测的实现方法。     

Noise measurements on standard RF power meters

The modern radio-frequency power meters used to realize the power primary standards are based on bolometric detectors direct-current biased by means of a self-balancing current loop. We have updated the electronic components of a self balancing circuit originally developed by NIST and evaluated its performance in the terms of Noise Equivalent Power. The performed measurements give NEP = 1.5 × 10⁻¹⁰ W/√Hz for the whole power meter and a NEP_Electronic = 1.2 × 10⁻¹⁰ W/√Hz for the electronic component at a temperature of 296 K.     

Accurate Thermal Conductance and Impedance Measurements of Transition Edge Sensors

Past measurements of the thermal coupling of superconducting transition edge sensor (TES) calorimeters suspended on SiN membranes produced wide-ranging values for the exponent of the thermal coupling through the membranes. We present a measurement technique that is less susceptible to current dependence of the phase transition than the previous measurements. An initial measurement produced the expected exponent for a 2-D phonon gas: thermal conductance is proportional to T ². In doing these measurements, we employ a modification to Lindeman’s equivalent circuit technique for measuring TES complex impedance.      

A Kilopixel Array of TES Bolometers for ACT: Development, Testing, and First Light

The Millimeter Bolometer Array Camera (MBAC) will be installed on the 6-meter Atacama Cosmology Telescope (ACT) in late 2007. For the first season of observations, MBAC will comprise a 145 GHz diffraction-limited, 1024-pixel, focal plane array of Transition Edge Sensor (TES) Bolometers. This will be the largest array of pop-up-detector bolometers ever fielded as well as one of the largest arrays of TES bolometers. We discuss the design specifications for the array and pre-assembly testing procedures for the cryogenic components. We present dark measurements of the TES bolometer properties of numerous 32-pixel columns that have been assembled into the first kilopixel array for ACT, as well as optical measurements made with our 256-pixel prototype array, including first light measurements on ACT.      

非制冷微测辐射热计热成像

文中在指出现代制冷型红外成像技术的不足,论述非制冷红外成像技术的优点之后,介绍了微测辐射热计阵列的非制冷热成像系统.首先与非制冷热电热像仪进行了比较,指出测辐射热计热成像的优势.然后描写了微测辐射热计阵列的设计,分析了桥式结构热绝缘对响应率提高所起的作用,并讨论了探测器噪声等效温差(NETD)的性能.最后概括地描述了微测辐射热计成像仪的设计.     

Automated in situ line of sight calibration of ASDEX Upgrade bolometers

The ITER Bolometer Robot Test Rig (IBOROB) is a robot-based diagnostic tool, which allows the measurement of the lines of sight (LOS) of the ITER bolometer prototypes. Up to now, it was only used as a LOS characterization device for the ITER collimator development. IBOROB was further developed and can now be operated in ASDEX Upgrade during a regular maintenance shutdown. At present, once a diagnostic like the bolometry is mounted inside the vessel, the actual LOS orientations are not measured, they are derived from CAD. The new procedure allows the fully automatic three-dimensional in situ measurement of bolometer LOS. The spatial distribution, the poloidal and toroidal alignment in the experiment coordinate system (CS), can be determined. The absolute accuracy, in reference to the tokamak CS, is provided by an additional calibration performed with a measurement arm by FARO Technologies Inc. Therefore, the amount of misalignment from the theoretical expectations can be quantified. In addition specific camera type dependencies such as internal camera reflections can be identified. Due to the high position accuracy of the robot, the LOS can be resolved with a spatial resolution of up to 0.1°. The method is explained in detail and results from two exemplary bolometer foil cameras obtained in a first set-up in ASDEX Upgrade are presented. The different steps and components needed to apply the measurements in the vessel are described with a focus on the constraints, e.g. geometrical, for an application of this method in a tokamak. Finally the consequences of the results are extrapolated to ITER and evaluated.     

The performance improvement evaluation for SiGe-based IR detectors

During recent years, single crystalline (Sc) SiGe has been recognized as a new low cost thermistor material for IR detection. In this study the effect of Ge content, pixel size and the Ni silicide on the performance of SiGe/Si thermistor material have been presented. The noise level was decreased for more than one order of magnitude when the Ni silicide layer was integrated below the metal contacts. The silicidation slightly improved TCR values for the detectors (+0.22%/K). However, increasing the Ge content had the most significant effect on the TCR. A statistical analysis was applied to evaluate the effect of each parameter. Using the factorial method, it was realized that decreasing the pixel size would enhance the TCR value.     

Thermal conductivity measurements of PTFE and Al2O3 ceramic at sub-Kelvin temperatures

The design of low temperature bolometric detectors for rare event searches necessitates careful selection and characterization of structural materials based on their thermal properties. We measure the thermal conductivities of polytetrafluoroethylene (PTFE) and Al₂O₃ ceramic (alumina) in the temperature ranges of 0.17–0.43 K and 0.1–1.3 K, respectively. For the former, we observe a quadratic temperature dependence across the entire measured range. For the latter, we see a cubic dependence on temperature above 0.3 K, with a linear contribution below that temperature. This paper presents our measurement techniques, results, and theoretical discussions.