High precision comparison between SNS and SIS Josephson voltagestandards

Recently, a new Josephson voltage standard based on a 1 V programmable chip provided by the National Institute of Standards and Technology (NIST) was implemented at the Swiss Federal Office of Metrology (OFMET). A comparison with a conventional Josephson voltage standard showed an agreement of (1.4±3.4)×10^-10 at 1 V. This result demonstrates the new system is functioning properly and can be used in various types of measurements. In particular, it will be one of the key components of the Watt balance experiment (1999) at OFMET     

A Method of Calibrating Standard Voltage Dividers up to 1000 V

A method of calibrating a resistive voltage divider for voltage ratios of 1000 V/10 V and 100 V/10 V with an uncertainty at the level of 10⁻⁷ is developed. The method enables a calibration to be carried out at the working voltage of the divider and can be used to calibrate a transportable voltage ratio standard when carrying out CCEM-K8 key comparisons.__________Translated from Izmeritel’naya Tekhnika, No. 4, pp. 52–57, April, 2005.     

Key comparisons of the VNIIM and BIPM voltage standards

The results of key comparisons of the national primary standard of Russia for the unit of electrical voltage, the volt, at the Mendeleev Institute of Metrology (VNIIM) with the Josephson effect voltage standard at the BIPM are reported. For these measurements, VNIIM provided a voltage measure based on the Josephson effect with a nominal output voltage of 10 V. Measurements were made with apparatus from the BIPM voltage standard. The VNIIM voltage measure is planned for use as a transfer standard for comparison with national standards for the volt. The comparisons indicate a high degree of equivalence of the compared VNIIM and BIPM primary standards with a relative combined standard uncertainty of 2·10–10 at 10 V.     

Investigation of the error in transferring the dimensions of the volt using a transportable stabilitron voltage standard

The results of an investigation of the characteristics of transportable voltage standards based on stabilitrons for the purpose of using them as standards of comparison when transferring the dimension of the unit of constant voltage in accordance with the State Standard GOST 8.027-2001 are presented. It is shown that, using the standard investigated, one can transfer the dimensions of the unit of voltage with an overall relative error of 5·10⁻⁸ for a voltage of both 1.018 V and 10 V. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 34–38, January, 2006.     

Comparison of a Multichip 10-V Programmable Josephson Voltage Standard System With a Superconductor–Insulator–Superconductor-Based Conventional System

We developed a 10-V dc programmable Josephson voltage standard (PJVS) using a multichip technique. The PJVS was based on $hbox{NbN/TiN}_{x}/hbox{NbN}$ junctions and operated using a 10-K compact cryocooler. We carried out an indirect comparison with a superconductor–insulator–superconductor-based conventional Josephson voltage standard (JVS) by measuring the voltage of a 10-V zener diode reference standard. The combined standard uncertainty of the comparison was $u_{c} = 0.03 muhbox{V}(k = 1)$, and the relative combined standard uncertainty was $3 times 10^{-9}$.      

High precision measurement of DC voltage ratios from 20 V/10 V to1000 V/10 V

This paper presents a new method of calibrating de voltage ratios from 20 V: 10 V to 1000 V: 10 V. A new battery-powered differential voltage detector has been developed to reduce the uncertainty of the measurement system. An absolute self-calibration process was used and traceability to a voltage ratio standard is not necessary. The uncertainties of dc voltage ratios (20 V to 1000 V): 10 V were less than 2 × 10^-7     

First Direct Comparison of a Cryocooler-Based Josephson Voltage Standard System at 10 V

A commercially available and fully automated 10-V Josephson voltage standard system with a liquid helium free cooling has been developed as a result of the cooperation between the Institute of Photonic Technology and Supracon AG, both in Jena, Germany. The system operates with an array of 19 700 superconductor–insulator–superconductor Josephson tunnel junctions installed in a pulse tube cooler. A stable operation is achieved by the proper integration of the voltage standard circuit to the cold stage of the cryocooler. Different operation setups are discussed. A direct comparison of a cryocooler-based Josephson voltage standard system versus a liquid-helium-based system was performed at a voltage level of 10 V. We obtained a voltage difference of 1.3 nV with a total combined uncertainty of 2 nV. This corresponds to a relative uncertainty of $2 times 10^{-10}$.      

Comparison of the Josephson voltage standards of VNIIM and PTB

Comparisons of the 1 V Josephson array voltage standard (JAVS) of the “D.I. Mendeleyev Institute for Metrology” (VNIIM), Russia, with that of the Physikalisch-Technische Bundesanstalt (PTB), Germany, were carried out in St. Petersburg in June 1999. The results of the direct comparison agree within an overall standard uncertainty of less than 1 nV. The results also show that direct comparisons are useful for detecting voltage offsets of a few parts in 10¹⁰. The reason for a small voltage offset in an SIS array was investigated at zero voltage level     

一种脉宽调制的高稳定连续可调直流电压源

介绍了一种以深埋齐纳电压基准元件LTZ1000A主电路为基础,结合脉宽调制技术实现的在0～10 V范围内连续可调的高稳定直流电压源。选用精密电阻并采用适当的保温与隔离措施,实现了电压基准主电路输出高稳定7 V电压,其短期稳定性达到1.7×10^-8。利用具有相同温度系数和阻值的精密电阻组成比例升压电阻网络,使输出10 V电压的短期稳定性为2.4×10^-8。同时利用脉宽调制并经DC-DC转换电路及滤波电路得到0～10 V的电压输出,短期稳定性可在10^-7量级左右。     

高电压脉冲校准装置研究

为解决高电压脉冲的校准问题,对高电压脉冲的校准方法进行研究,并建立了一套脉冲校准装置。校准装置将高电压脉冲信号进行电压转换,变为脉冲小电压,通过数据采集系统,在频带范围10Hz~1kHz、电压范围1~1600V内,对脉冲电压的关键参数进行测量,得到高电压脉冲的电压幅度、脉冲频率、脉冲宽度、上升时间和下降时间。通过实验室标准仪器设备对高电压脉冲校准装置进行测试,其中脉冲幅度的测量误差为 0.02%~0.4%。     

A Two-Way Josephson Voltage Standard Comparison Between NIST and NRC

A two-way Josephson voltage standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the National Research Council (NRC) has been conducted. The process consists of two comparisons: first, using the NRC JVS with the NRC's measuring system (hardware and software) to measure the 10 V provided by the NIST JVS and then using the NIST JVS measuring system to measure the 10 V provided by the NRC JVS. The results of the two comparisons are in agreement to within 0.7 nV, and their mean indicates that the difference between the two JVSs at 10 V is $-$0.28 nV, with a pooled combined uncertainty of 2.07 nV $(k = 2)$ or a relative uncertainty of 2.1 parts in $10^{10}$.      

交流电压源毫伏级量值准确测量的技术研究

基于电压比例和交直流转换技术,提出了一种对交流电压源的毫伏级量值进行准确测量的方法。采用自行研制的二进制级联结构电压比例装置和792A交直流转换标准,将被测交流电压源的毫伏级量值溯源至交流电压国家基准。实验采用替代测量法,通过选用不同电压比例和不同792A量程的组合,在55Hz~5kHz频率范围内,对1台5720A多功能校准源10~200mV范围的交流电压进行准确测量。结果表明,各毫伏级交流电压示值相对误差的绝对值均不超过±40μV/V,测量结果扩展不确定度优于80μV/V,满足交流电压源毫伏级量值溯源需求。     

A compact comparison standard based on the Josephson effect with an output voltage of 10 V

A compact comparison standard in the form of a voltage measure based on the Josephson effect with an output voltage of 10 V is developed. The purpose of the standard is to carry out international comparisons of stationary standards of the volt based on the Josephson effect and provide traceability of the measurements made using the Russian State Primary Standard of the volt, with the BIPM standard of the volt with a relative uncertainty of less than 2⋅10⁻¹⁰. The comparison standard apparatus is placed in a case which protects it when it is transported.     

A simple accurate bridge-transducer interface with continuousautocalibration

This paper presents a one-chip simple and accurate transducer interface for resistive bridges. A key part of this interface is formed by a novel dynamic voltage divider. In this divider the bridge supply voltage is measured for reference purposes in small parts (piece-wise measurement) which are within the range of the bridge output voltage. The use of an autocalibration technique, the three-signal method, eliminates influeuce of linear parameters and errors. Moreover, the effects of the nonidealities of the applied switches are also eliminated. The circuit has been realized in a 3 μm BiCMOS process and shows an uncertainty of only 10 μV for a bridge supply voltage of 5 V     

A low-noise latching comparator probe for waveform sampling applications

A new latching comparator probe is described. The probe is being developed as part of an effort to augment voltage measurement capability in the 10 Hz to 1 MHz frequency range. The probe offers an input voltage range of /spl plusmn/10 V, input impedance of 1 M/spl Omega/ and root mean square noise referred to the input as low as 55 /spl mu/V. The probe's 3-dB bandwidth is approximately 20 MHz. Total harmonic distortion is as low as -93 dB at 50 kHz. Gain flatness is within /spl plusmn/10 /spl mu/V/V from 100 Hz to 100 kHz. Improved step settling performance is achieved using a technique that minimizes circuit thermal errors. The probe's input range can be extended with a frequency-compensated 1-M/spl Omega/ input impedance attenuator allowing measurement of pulses in the microsecond regime up to 100 V. The attenuator can be compensated further with a digital filtering algorithm to achieve gain accuracy better than 100 /spl mu/V/V.     

Low operating voltage single ZnO nanowire field-effect transistors enabled by self-assembled organic gate nanodielectrics

The development of nanowire transistors enabled by appropriate dielectrics is of great interest for flexible electronic and display applications. In this study, nanowire field-effect transistors (NW-FETs) composed of individual ZnO nanowires are fabricated using a self-assembled superlattice (SAS) as the gate insulator. The 15-nm SAS film used in this study consists of four interlinked layer-by-layer self-assembled organic monolayers and exhibits excellent insulating properties with a large specific capacitance, 180 nF/cm2, and a low leakage current density, 1 x 10(-8) A/cm2. SAS-based ZnO NW-FETs display excellent drain current saturation at Vds = 0.5 V, a threshold voltage (Vth) of -0.4 V, a channel mobility of approximately 196 cm2/V s, an on-off current ratio of approximately 10(4), and a subthreshold slope of 400 mV/dec. For comparison, ZnO NW-FETs are also fabricated using 70-nm SiO2 as the gate insulator. Implementation of the SAS gate dielectric reduces the NW-FET operating voltage dramatically with more than 1 order of magnitude enhancement of the on-current. These results strongly indicate that SAS-based ZnO NW-FETs are promising candidates for future flexible display and logic technologies.     

Direct comparison of two independent Josephson voltage standards at1 V and precision measurements up to 10 V

Two Josephson voltage standards have been compared using a room-temperature electronic nanovoltmeter with a peak-to-peak noise of about 2 nV at the 1-V level corresponding to a RMS uncertainty of 4×10^-10. The excellent stability in maintaining the desired voltage steps makes it possible to obtain recorder traces comparing Nb/Al₂O₃/Nb Josephson standards with Weston cells and Zener reference standards at 1 V and 10 V. At 10 V the best result shows a peak-to-peak noise of 250 nV corresponding to a RMS uncertainty of 5×10^-9 for a Zener reference and 50 nV corresponding to 1×10^-9 for a series connection of nine Weston cells. As an example for the application of the Josephson standard as a potentiometer the deviation in the linearity of a digital voltmeter is confirmed to be on the order of 0.1 p.p.m. in the range from -10 V to +10 V     

Portable Comparison Standard Based on the Josephson Effect

A comparison standard is developed in the form of a small voltage standard based on the Josephson effect whose metrological characteristics make it possible to compare stationary voltage standards with uncertainty less than 10^–9. The standard was used in key comparisons of national voltage standards within the framework of Euromet Project N 723.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 48–51, February, 2005.     

Evaluation of The Performance of Portable New Design High DC Voltage Measuring System up 40 kV

Portable DC high voltage (HV) measuring system up to 40 kV has been designed and built with DC HV probe and AC/DC voltmeter developed at TUBITAK UME (The Scientific and Technological Research Council of Turkey). The structure and construction of the HV probe and DC voltmeter for evaluating their performance are described. The comparison measurements have been done using the reference DC HV system up to 40 kV. The voltmeter described here was developed for using in the measurement or calibration of DC HVs with high input impedance greater than 100 MΩ. The voltage error obtained in comparison measurements is less than 100 μV/V at 40 kV.