Development of Low Temperature SQUID Gradiometer Array for Metallic Magnetic Microcalorimeters

We report on the performance of two types of SQUID gradiometers developed for the readout of magnetic calorimeters. Our previously developed low dissipation SQUID gradiometer optimized for low temperature operation has demonstrated the flux noise level of under a magnetic field of 2.5 mT and 150 mK. With a cylindrical Au:Er paramagnetic sensor mounted inside the octagonal pickup washer of the SQUID gradiometer, we succeeded in detecting X-ray signals. However, our achieved energy resolution was 47.2±2.1 eV at 5.9 keV limited by the high operating temperature of 150 mK and by a magnetic field, small for that temperature, due to the limited critical current of the field coils. Based on these results, we fabricated new arrays of SQUID gradiometer by tuning the line width and the number of turns of the field coils and shunt resistance to realize a lower noise level and a larger magnetic field. Furthermore, arrays of SQUID gradiometer with meander patterned pickup washer was fabricated which provides a stronger coupling between the paramagnetic sensor and the pickup washer, and a larger magnetic field at the sensor.      

Current Sensitivity Enhancement of a Quasi-One-Junction SQUID Comparator as an Input Circuit of SFQ Readout Circuit for a Superconducting Detector

We evaluated the current sensitivity of a quasi-one-junction SQUID (QOS) comparator with an input transformer at 4.2 K. A comparator based on a QOS is promising for constructing the single flux quantum (SFQ) readout circuits of an array system of multiple superconducting detectors.The QOS comparator is made of three Nb/AlO \(_x\) /Nb Josephson junctions, senses an output signal of a superconductor detector, and generates the SFQ pulses.There are strong demands for enhancing the current sensitivity of the QOS comparator because an output current from superconducting detector typically remains at the magnitude of a few \(\upmu \) A. We fabricated the QOS comparator with an input transformer using AIST Standard Process 2, where the critical current density of the Josephson junctions is chosen as high as 2.5 kA/cm \(^{2}\) . We designed the input transformer to enhance the current sensitivity under the conditions of 200  \(\upmu \) m  \(\times \)  200  \(\upmu \) m in size and 20:1 in turn ratio. Consequently, we succeeded in reducing a gray zone width of the comparator, and achieved the current sensitivity of 400 nA at 4.2 K in the low frequency range.     

光电感烟火灾探测器的电路设计

详细介绍了光电感烟火探测器电路的各部分工作原理和设计要点，该电路具有用μＡ级电流驱动ｍＡ级器件工作的特点，有抗干扰电路，在很大程度上提高了火灾报警的可靠性，因此，具有一下的理论水平及很大的实用价值。     

X-ray Detection Performance of 100-pixel Superconducting Tunnel Junction Array Detector in the Soft X-ray Region

The overall performance of a 100-pixel superconducting tunnel junction (STJ) array detector in the soft X-ray region was determined by measuring fluorescent X-rays from light elements. The yield of working STJs in the fabricated detector was?90%, and the leakage current for these 90?STJs was 11.6±2.5?nA. The STJs had an intrinsic energy resolution for O-Kα X-rays (524.9?eV) of 10.2±1.7?eV (FWHM). The deviation from energy linearity was ?0.042±0.45%, 0.793±0.91%, and 0.135±1.31% for O-Kα (524.9?eV), N-Kα (392.4?eV) and B-Kα (183.3?eV) X-rays, respectively. Most of the STJs exhibited uniform X-ray detection characteristics. In addition, the detector could discriminate the N-Kα peak in the fluorescent X-ray spectrum from n-type SiC doped with 300?ppm nitrogen.     

高速X射线线阵探测器噪声分析与滤波方法

对高速X射线线阵探测器的噪声进行了分析,将探测器噪声分为本底噪声、随机噪声、孤立噪点三种类型。通过实验,研究了随着探测器扫描速度增加,噪声的变化情况;分析了扫描速度越快噪声对探测器探测结果影响越大的原因。提出了一种适用于高速X射线线阵探测器的滤波方法:采用差值法滤除本底噪声;采用卡尔曼滤波器滤除随机噪声;采用根据噪声特点改进的中值滤波法滤除孤立噪点。实验证明,该方法既可以有效滤除探测器各类噪声,又能很好的保持探测器探测图像的细节。     

太赫兹阵列探测器响应度校准溯源研究

提出了一种太赫兹阵列探测器响应度校准溯源方法。首先,使用阵列探测器的每一像元对太赫兹辐照场中心进行逐一扫描,识别有效像元、死像元和过热像元,并对有效像元响应值进行归一化处理,获得阵列探测器的相对辐照度响应值。其次,使用中心像元对太赫兹辐照场进行扫描测量,扫描总面积大于太赫兹光斑尺寸,保证太赫兹功率被完整测量,获得中心像元与其他有效像元的太赫兹功率响应值。最后,用标准太赫兹功率计标定高莱功率计,扩展太赫兹功率校准量限,实现微瓦级太赫兹辐射功率测量溯源,用高莱功率计测得的太赫兹辐射源总功率对阵列探测器测得的积分响应值进行校准,得到阵列探测器辐照度响应绝对值。对探测器进行测量校准和不确定度分析,测得辐照度响应度的相对扩展不确定度为Urel=20%(k=2),测量结果可溯源至国家太赫兹辐射功率标准。     

新型室温微机械红外探测器原理与设计

利用红外吸收气体直接吸收红外辐射的原理,设计出一种新型室温红外探测器。当密闭腔 内气体吸收红外辐射后,腔内压强增大使弹性薄膜形变,由以弹性薄膜为可动极板的微电容结构的电容变化量,可测得红外辐射的大小。采用微机械技术制作的探测器,对8-14mm红外辐射有灵敏、快速的响应,灵敏度≥2×10-3 pF/mW。     

Null Detector Circuit Design Scheme for Detecting Defective AC-Coupled Capacitors in Differential Signaling

This paper presents a novel method for detecting defective ac-coupling capacitors in high-speed differential signaling connections by designing a circuit with null detectors at the differential receiver. The design parameters of selecting the null ranges in the receiver buffer are proposed to efficiently detect the voltage droop that creates erroneous jitter. The null detectors in the proposed method enable the use of a lower test signal speed than the mission data rate at differential connections to detect defective capacitors. The proposed design method of null detectors combines four design and test factors, namely, regular null, voltage doubling, fail–safe, and defect sensitization, to determine the stretched null used for test purposes. The null-detection scheme has been implemented and verified in the design using a regular current-mode logic (CML) differential buffer in the 0.18- $muhbox{m}$ complementary metal–oxide–semiconductor (CMOS) process. The detection capability of the proposed method to check for traditional defects with the same null detector is also demonstrated through SPICE-based fault simulations. The proposed method is also verified with the board developed for parameter measurements. The parameters proposed in this paper showed excellent agreement among calculated, simulated, and measured values. In particular, measured parameters showed strong closeness up to 99% to its calculated values.      

白炽灯色温测量装置电路设计

介绍利用单片单板机接口电路完成对６Ｖ、３０Ｗ白炽灯光源与其对应的标准白炽灯光源的色温比对标定工作。     

高温超导红外探测器的互连电路设计

对高温超导测热辐射计在红外热成象研究的应用方面作探索性研究，根据高温超导Ｂｏｏｍｅｔｅｒ的探测机理和噪声理论，设计与之相匹配的电路系统，实现对探测信号的不失真的放大，传输和处理，为高温超导红探测器实用化研究提供实验依据，也获得热成象系统初步探索经验。     

解析JJF 1326-2011质量比较仪校准规范

本文以METTLER-TOLED XP56质量比较仪(最大秤量Max:56g,实际分度值d:1ug)的校准为例,详细分析了JJF1326-2011《质量比较仪校准规范》的适用范围、计量特征和校准方法,希望有助于人们正确理解该“校准规范”,正确进行质量比较仪的校准.     

Physical Principles of Low Temperature Detectors: Ultimate Performance Limits and Current Detector Capabilities

The rapid development of low temperature thermal detectors since the early 1980s has resulted in remarkable improvements in the sensitivity and precision of many types of measurements. We will discuss the operating principles of these detectors in the most general possible terms. We will try to show how the physics of some popular thermometer systems introduces performance limits, and how the different figures of merit and optimizations that result affect various applications.      

PID温度控制装置的电路设计

本文介绍了过程温度控制PID电路和可控硅触发电路的设计及其工作原理，作者在设计电路的基础上开发了温度控制装置，并用该套温控装置进行水温控制试验，取得较为满意的效果。     

对小型低温速冻库的设计实例分析

本文通过设计实例对小型速冻冷库的设计思路、方案以及机器设备的选型作一下介绍。     

低温槽车排液自增压汽化器的设计计算

从强度要求、排液流速要求诸方面出发，讨论了低温槽车排液用自增压汽化器的性能参数选择及其设计计算。     

质量比较仪测量结果的不确定度评定与分析

按照JJF1326-2011《质量比较仪校准规范》对质量比较仪进行重复性、偏载和局部示值误差测量.对测量结果的不确定度进行评定与分析,并指出不确定度主要来源.     

小型地磁传感器的低噪声前置放大电路设计

一些小型地磁传感器输出噪声电压水平在10 nV/Hz左右,现有nV级噪声水平的前置放大器体积太大难以满足其信号调理需求.针对这个问题,本文阐述了低噪声放大电路输入级设计原理,利用Multisim对输入级电路等效输入噪声电压等指标进行仿真,研制出一种基于差分输入的小型低噪声前置放大电路.给出了电路关键性能指标的仿真和测试结果,测试结果表明该电路具有良好的噪声特性和共模抑制比,噪声电压水平仅为3.7 nV/(Hz)～(1/2)@3.5 kHz,共模抑制比110 dB,增益为100～1 000连续可调.     

K型热电偶自动补偿式测温电路的设计与校准

介绍一种新型数字式测温仪表的电路设计原理与校准方法。其特点是在测温电桥中,利用硅管PN结的负温度系数去补偿K型热电偶的正温度系数,全部量程实现了自动温度补偿,并能直接测量室温。它具有准确度高,分辨力强等优点。     

基于SQUID的直流电阻电桥指零仪设计

设计了一款基于超导量子干涉仪(SQUID)的直流电阻电桥指零仪电路,该电路可用作高精度电阻电桥中低值电阻(0.1~100Ω)测量的指零仪电路。通过自制SQUID外围电路并优化电路其输入耦合线圈的互感值,实现微弱电桥不平衡电流的精密测量。与传统电阻电桥基于测量不平衡电压的纳伏计指零仪相比,其检测灵敏度在中低值电阻测量范围有数量级的提升。设计的作为指零仪的SQUID磁通锁定环1/f转折频率在2Hz左右,磁通白噪声水平在3.5μΦ₀/左右,并且输入线圈与SQUID互感系数高达10nH,其等效的电流白噪声密度0.7pA/。将其用作电阻电桥指零仪测量100Ω标准电阻(工作电流为10mA)的分辨率可达到10^-11量级。