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1.
《IEEE transactions on instrumentation and measurement》1974,23(4):264-267
The design and operation of a cryogenic voltage comparator system for precision 2e/h measurements is described. Major improvements embodied in the new 2e/h system include the use of 1) a single microstripline-coupled Josephson tunnel junction to obtain usable step voltages up to 10 mV at 10.0 GHz, 2) a cryogenic voltage divider comprised of two resistors whose ratio is calibrated with a low-temperature dc current comparator, 3) a superconducting quantum interference device (SQUID) null detector, and 4) superconducting switching. The accuracy of the present 196:1 divider system is estimated to be about 2 parts in 108 on the basis of preliminary tests and is limited by resistor self-heating during calibration. 相似文献
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基于虚拟仪器的PCBA多通道视觉检测系统 总被引:1,自引:1,他引:0
在检测误判率足够低的前提下,检测速度通常是制约视觉检测系统在线应用的关键因素.鉴于PCB图像具有大面积绿色阻焊膜且目标组件的位置相对固定的特点,本文提出了一种以区域分割思想为基础的多通道检测技术,用以提高PCBA视觉检测系统的检测速度.首先以单个组件的区域为基本单元,将PCB图像划分为多个独立小区域;然后将系统设置成多个同步检测的通道,并将分割好的小区域图像按照预先设定的顺序分别同时送入不同的通道内进行同步检测;最后基于虚拟仪器开发平台L abV IEW及其视觉开发工具IM AQ V is ion开发出了PCBA 10通道视觉检测系统.通过实验证实,折算之后,10通道系统的单片元件最大检测时间是12.5 m s,内存消耗量是205.0 KB;100通道系统的单片元件最大检测时间是1.25 m s,内存消耗量是2 050 KB. 相似文献
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T. Wada H. Nagata H. Ikeda Y. Arai M. Ohno K. Nagase 《Journal of Low Temperature Physics》2012,167(5-6):602-608
We are developing low power cryogenic readout integrated circuits (ROICs) for large format far-infrared image sensors using fully-depleted-silicon-on-insulator (FD-SOI) CMOS technology. We have evaluated the characteristics of MOS FETs fabricated by the FD-SOI CMOS technology and have found that both p-ch and n-ch FETs show good static performance below the liquid helium temperature, where n-ch FETs fabricated by conventional bulk-CMOS technology usually suffer from anomalous behaviors such as kink and hysteresis. We have also designed and fabricated an operational amplifier (OP-AMP) and have successfully demonstrated that the OP-AMP works at the liquid helium temperature with an open loop gain of 7000 and a power consumption of 1.3 μW. The noise is dominated by mainly 1/f and has a value of at?1?Hz. 相似文献
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C. Arnaboldi A. Giachero C. Gotti M. Maino G. Pessina 《Journal of Low Temperature Physics》2012,167(5-6):620-625
The complete readout and biasing system for the MARE experiment in Milan is presented. The experiment aims at a direct measurement of the neutrino mass, and is based on an array of microcalorimeters coupled to semiconductor thermistors. The readout is based on JFETs operated inside the cryostat at cold (130?K), to buffer the voltage signal from the thermistors. The sources of the JFETs are fed into second stage amplifiers with very low noise (less than $0.5~\mathrm{nV}/\sqrt{\mathrm{Hz}}$ white noise) and programmable high gain. The outputs are then processed by Bessel filters and acquired with a commercial DAQ system. Every 20 channels, an additional group of 4 is used to amplify the ground reference from inside the cryostat; this common ground signal is then subtracted from each channel. This approach allows to recover a fully differential readout with a smaller number of cables with respect to the standard differential configuration. The detector bias is programmable in voltage and sign with 8-bit resolution. A test signal can be superimposed on the bias voltage, in order to test each channel individually. All the readout system is remotely programmable from a PC, coupled through optical fibers. 相似文献
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本文阐述了优化 CCD 摄象光学系统的设计思想。从满足 CCD 摄象系统的测量精度出发,采用优化设计的方法,探索了 CCD 摄象光学系统结构型式及各种性能参数设计的新途径。实践证明,这是设计 CCD 摄象光学系统的一种经济、有效的方法。 相似文献
7.
《低温学》1987,27(2):73-76
A brushless d.c. torque motor for application under vacuum in the temperature range 4–300 K is described. As well as being used as a motor this system can also be used as a positioner offering high angular resolution and positioning accuracy and an unlimited angular excursion or as a 15° stepper motor. The motor was specially developed for application in space telescopes, i.e. for highly accurate positioning of components in cold optical instruments. It has been considered for use in CRISTA and in the ISOCAM experiment. In addition to its application as a torquer and positioner this system can also be used as an efficient power generator or power transformer. Its high electromechanical efficiency, its safety of operation and its long lifetime are features which make it well suited for space application. 相似文献
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C. Macculi L. Colasanti S. Lotti L. Natalucci L. Piro D. Bagliani M. Biasotti F. Gatti G. Torrioli M. Barbera G. La Rosa T. Mineo E. Perinati 《Journal of Low Temperature Physics》2012,167(5-6):783-794
The TES cryogenic detectors, due to their high spectral resolution and imaging capability in the soft X-ray domain, are the reference devices for the next proposed space missions whose aims are to characterize the spectra of faint or diffuse sources. ATHENA is the re-scoped IXO mission, and one of its focal plane instrument is the X-ray Microcalorimeter Spectrometer (XMS) working in the energy range 0.3–10?keV. XMS will be able to achieve the proposed scientific goals if a background lower than 0.02?cts/cm2/s/keV is guaranteed. The studies performed by GEANT4 simulations depict a scenario where it is mandatory to use an active Anti-Coincidence (AC) to reduce the expected background in the L2 orbit down to the required level. This is possible using a cryogenic AC detector able to provide a rejection efficiency of about 99%. We are developing for this purpose a TES-based detector made by Silicon absorbers (total assembled area about 1?cm2 and 300?μm thick) and sensed by a Ir:Au TES. All the work done for IXO is applicable to ATHENA, with more margins due to the smaller area required for the detector. Here we present the results obtained from different samples, as a step towards the final detector design. 相似文献
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J. van?der Kuur J. Beyer M. Bruijn J. R. Gao R. den Hartog R. Heijmering H. Hoevers B. Jackson B. J. van Leeuwen M. Lindeman M. Kiviranta P. de Korte P. Mauskopf P. de Korte H. van Weers S. Withington 《Journal of Low Temperature Physics》2012,167(5-6):561-567
SAFARI is an imaging Fourier Transform Spectrometer for 35–200 μm under development for flight on the Japanese IR-satellite SPICA (2018). The 3.25?m diameter actively cooled telescope (<6K) will provide a sky background limited signal, which implies that detectors will need to have an NEP of $3.5 \cdot10^{-19}\ \mbox{W/}\sqrt{\mathrm{Hz}}$ in order not to be limiting the sensitivity. The instrument will utilize three TES-based detector arrays, covering the 2×2 arcmin field-of-view in three octaves of wave length. This contribution will present an overview of the detector sub-system, i.e.: the detector arrays and radiation coupling, the focal plane assembly, the amplification chain and the frequency-domain- multiplexed electronics. The focus will be on the implications on the system design of the readout under the stringent power dissipation, heat load, and weight limitations. 相似文献
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A. Nucciotti F. Alessandria M. Ameri C. Bucci A. Bersani L. Canonica R. Cereseto G. Ceruti O. Cremonesi A. Dally V. Datskov S. Dossena L. Ejzak M. Faverzani E. Ferri A. Franceschi G. Gregerson K. Heeger C. Ligi T. Napolitano D. Orlandi M. Sisti L. Taffarello L. Tatananni T. Wise A. Woodcraft 《Journal of Low Temperature Physics》2012,167(3-4):528-534
The CUORE detector will be made of 988 TeO2 crystals and will need a base temperature lower than 10 mK in order to meet the performance specifications. To cool the CUORE detector a large cryogen-free cryostat with five pulse tubes and one specially designed high-power dilution refrigerator has been designed. The detector assembly has a total mass of about 1.5 ton and uses a vibration decoupling suspension system. Because of the stringent requirements regarding radioactivity, about 12 tons of lead shielding need to be cooled to 4?K and below, and only a limited number of construction materials are acceptable. The eight retractable radioactive sources for detector calibration and about 2600 signal wires add further complexity to the system. The many stringent and contrasting requirements together with the overall large size made the design of the CUORE cryogenic system a real mechanical and cryogenic engineering challenge. The cryogenic system is expected to be fully operational in the Gran Sasso Laboratory in July 2013. We report here about the current status of the cryogenic system construction, which has started about one year. 相似文献
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针对目前国内实验室校准温湿度变送器时,都需要用多台仪表及直流稳压电源进行组合测量的缺点,设计了一体化温湿度变送器自动测量装置。该装置电路系统基于STM32F103微控制器和ADS1256ADC芯片为核心研究设计多路信号采样测量控制系统;上位机应用程序采用LABVIEW开发平台与数据库技术设计实现。可以同时测量34路变送器,实现变送器自动供电、信号类型自动识别、自动数据处理与显示存储、无线数据传输、自动生成测量报告以及仪器自动校准等功能。该装置的电流、电压采样精度高达0.05%,具有测量效率高、成本低、智能化程度高等特点。 相似文献
17.
R. Yamamoto K. Sakai Y. Takei N. Y. Yamasaki K. Mitsuda 《Journal of Low Temperature Physics》2014,176(3-4):453-458
Frequency division multiplexing (FDM) is a promising approach to read out a large format transition-edge sensor (TES) array for future astrophysical missions. We constructed a four channel FDM readout system using baseband feedback in the MHz band. We demonstrated the principle of our FDM method with an actual TES array, a multiplexing SQUID and LC band-pass filters under 100 mK. The resonant frequencies of LC filters were consistent with the design value with an accuracy of better than 3 %. We successfully obtained X-ray pulses from two TESs simultaneously but the energy resolution was degraded to about 100 eV at 5.9 keV and crosstalk effects were observed. The origin of the crosstalk effects is investigated by modified setups. Based on comparative experiments and numerical calculations, we conclude that the non-linearity of the SQUID is the cause of some of the crosstalk effects. Unlike the regular crosstalk effect from the adjoining channels, the crosstalk effect due to non-linearity observed in this paper occurs in all channels. Solving these problems will help us to obtain FDM readout with sufficient energy resolution. 相似文献
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M. Kenyon P. K. Day C. M. Bradford J. J. Bock H. G. Leduc 《Journal of Low Temperature Physics》2008,151(1-2):112-118
We built and measured the electrical properties of membrane-isolation transition-edge sensing bolometers (TESs) suitable for
background-limited far-IR/submillimeter direct-detection spectroscopy. Each TES consists of a Mo/Au bilayer patterned onto
a suspended, thermally isolated absorber that is connected to the substrate through four Si
x
N
y
beams deposited by low pressure chemical vapor deposition (LPCVD). We fabricated TESs with straight and meander support beams.
The dimensions of the meander (straight) support beams are 700 μm (700 μm) long by 0.25 μm (0.5 μm) thick by 0.35 μm (0.5 μm)
wide. We measured I–V characteristics for these TESs and determined that the thermal conductance G equals 72 fW/K (straight) and 19 fW/K (meander) for our best devices. The thermal conductance exhibits a T
1/2 dependence with temperature which is evidence of effective elastic scattering of the acoustic phonon modes. The transition
temperatures T
c
for the same TESs are T
c
=137 mK (straight) and T
c
=71 mK (meander). If we assume the TESs are temperature-fluctuation noise limited, then the derived noise equivalent power
(NEP) equals 1.9×10−19 W/Hz1/2 (straight) and 6.1×10−20 W/Hz1/2 (meander), using our measured values for G and T
c
. The meander-beam TES has a derived NEP that is close to two orders of magnitude lower than the state-of-the-art. Finally,
we measured an effective time constant τ of about 300 ms (straight) and 400 ms (meander) using electrical and optical pulses. These values for the NEP and τ for the meander-beam TES meet the requirements for the Background-Limited far-IR/Submillimeter Spectrograph (BLISS), a proposed
NASA instrument.
相似文献
19.
M. Kenyon A. D. Beyer B. Bumble P. M. Echternach W. A. Holmes C. M. Bradford 《Journal of Low Temperature Physics》2014,176(3-4):376-382
We have built and tested 32-element linear arrays of absorber-coupled transition-edge sensors (TESs) read out with a time-division SQUID multiplexer. This detector/readout architecture is designed for the background-limited far-IR/submm spectrograph (BLISS) which is a broadband (35–433 \(\upmu \) m), grating spectrometer consisting of six wavebands each with a modest resolution of R \(\sim \) 700. Since BLISS requires the effective noise equivalent power (NEP) of the TESs to equal 1 \(\times \) 10 \(^{-19}\) W/Hz \(^{1/2}\) , our detectors consist of very long (1–2 mm), narrow (0.4 \(\upmu \) m), and thin (0.25 \(\upmu \) m) Si \(_{x}\) N \(_{y}\) support beams that reduce the thermal conductance G between the substrate and the optical absorber. The thermistors of our lowest noise TESs consist of iridium with \(T_{c}=130\) mK. We have measured the electrical properties of arrays of these Ir TESs with various meander and straight support beams and absorber shapes and found that G is \(\sim \) 30 fW/K (meander) and \(\sim \) 110 fW/K (straight), the electrical NEP is 2–3 \(\times \) 10 \(^{-19}\) W/Hz \(^{1/2}\) (meander and straight), and the response time \(\tau \) is 10–30 ms (meander) and 2–5 ms (straight). To reduce spurious or “dark” power from heating the arrays, we mounted the arrays into light-tight niobium boxes and added custom L/R and L/C low-pass chip filters into these boxes to intercept dark power from the bias and readout circuit. We found the average dark power equals 1.3 and 4.6 fW for the boxes with L/R and L/C chip filters, respectively. We have built arrays with \(T_{c}= 70\) mK using molybdenum/copper bilayers and are working to lower the dark power by an order of magnitude so we can demonstrate NEP \(~=~1~\times \) 10 \(^{-19}\) W/Hz \(^{1/2}\) with these arrays. PACS numbers: 85.25.Pb; 95.85.Gn; 95.85.Fm; 63.22. \(+\) m 相似文献