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The problems of transfer Quantum Hall resistance to 1 Omega resistance standard with direct current comparator bridge (DCC) are introduced. Some effective technique ways are suggested by analyzing the possible causations of the measurement results' fluctuation. The comparing experiments between DCC and cryogenic current comparator bridge (CCC) have been performed with analyzing the uncertainty of...
We construct a frequency stabilized extended-cavity diode laser (ECDL) at 822.5 nm wavelength that could be a reliable frequency reference. The laser frequency is locked to the Cs 6S1/2rarr8S1/2 two-photon-transition (TPT) with the Allan deviation of 4.4times10-13 (60 s). The possible systematic error is evaluated as 2 kHz.
In this paper, a Zeeman slower suitable for Sr optical clock was designed and constructed through optimizing the winding number. The root mean squared deviations of the experimental data from theoretical data and computed data from theoretical data are both less than 0.5%.
The ISO GUM provides a framework for uncertainty evaluation using the law of propagation of uncertainty (GUF). The output quantity is characterized by a Gaussian or student-t distribution. Supplement one to the GUM deals with the propagation of probability distributions of the input quantities of a mathematical model of measurement for the evaluation of uncertainty by a Monte Carlo method. This paper...
By employing an array of 620 high-Tc Josephson junctions, we have achieved a maximum quantum output voltage with approximate value of 0.1 V at a temperature of 79.2 K and a frequency of 77.465 GHz. We also demonstrate that steps on the current-voltage characteristic of an array of bicrystal junctions at voltages of 70 mV were flat over the current range of 150 muA with a relative uncertainty of 0...
The paper presents an international comparison of ac-dc current transfer measurements at 10 mA and frequencies up to 1 MHz. The standards of NMIA, PTB and BEV have already been compared. The comparison is currently being extended to involve SP. The results will be presented at the conference.
This paper describes the design and verification of current shunts for AC-DC transfer measurements in the range 20 A to 100 A. The measured AC-DC current transfer difference of the 100 A shunt is -36 muA/A at 100 kHz with an uncertainty of 200 muA/A.
This paper describes an experiment which shows that the integer quantum Hall effect implemented in GaAs/AIGaAs Hall bars mounted as a Wheatstone bridge is reproducible with a relative uncertainty of less than 4 parts in 1011.
A precision measurement of the fractional quantized Hall resistance in a high mobility two-dimensional electron system was carried out as a test of the universality of the quantum Hall effect. Our results indicate that the Hall resistance at filling factor nu=1/3 does not deviate from the theoretical value 3ldrh/e2 within a relative uncertainty of plusmn3.3 parts in 108 (k=2).
A new type of coaxial shunts, with nominal current from 20 mA to 20 A have been designed at I.N.RI.M.. Different approaches have been used to built them, depending on their nominal current. In the currents between 100 mA and 20 A they are made as a disk structure, using either SMD resistors or manganin foils. In order to reduce stray effects, their structures have ideally no common magnetic interaction...
This paper describes the method used at BEV to determine the frequency dependence of thermal current converters at 10 mA in the frequency range 10 Hz to 1 MHz.
A four-terminal co-axial pair Maxwell-Wein bridge has been developed at NRC. The bridge is suitable for the determination of self-inductance in terms of resistance and capacitance in the frequency range of 800 Hz to 5 kHz. The bridge is primarily designed to measure the four-terminal definition of the impedance of a self-inductor but may be easily modified to measure one-terminal pair impedance using...
Accurate volume measurements for silicon spheres by optical interferometers play an important role in the determination of the Avogadro constant by the X-ray crystal density method. To reduce the uncertainty in the volume determination, a new vacuum chamber with a radiation shield has been developed. A new sphere temperature measurement system has been also introduced. Details of the improvements...
Flickermeter calibrations currently rely on the predicted response of a standard flickermeter to basic waveforms. A description is given of an interpretation and implementation of the IEC standard flickermeter, developed at NPL, in order to assess the response of commercial flickermeters to more complex waveforms, which are representative of signals that occur in practice. A description of the incorporation...
A new dual-heater thermal voltage converter (DH- TVC) with improved low-frequency performance has been developed at the AIST. Frequency characteristic of the DH-TVC was evaluated using a dual-output programmable Josephson voltage standard(DO-PJVS), and was confirmed to have low-frequency flatness better than 10-6 down to 1 Hz.
A description of the interference immunity testing of electrical products is given and the need for traceable calibration of the associated testing generators is described. A brief presentation of three analysis algorithms to calibrate testing generators is given.
High frequency power standard is quite everywhere implemented using the microcalorimeter technique. At INRiM a twin type coaxial microcalorimeter is used to measure the effective efficiency of thermoelectric detectors from direct current up to 40 GHz. However, below 10 MHz there is a lack of sensitivity that reduces the power standard accuracy. To work around the problem, we propose to calibrate the...
Published RF and microwave data on dielectric reference liquids [NPL Report CETM33] are reassessed to allow quoted measurement uncertainties to be reduced. The aim is to make the data maximally useful to users. The modelling approach followed should have application beyond dielectric metrology.
Dispersive Fourier transform spectroscopy (DFTS) provides us with a very effective technique for the measurement of absorption and refractive index spectra of environmentally hazardous gases. This paper presents the rotational transition lines and refractive index spectra of Nitrous Oxide gas as a function of varying pressure using DFTS for the very first time. The relationship between the variation...
In this paper, the consequence of a difference between effective and programmed aperture time of the HP3458 is evaluated. The frequency response and the compensation is strongly frequency dependant, and is a function of aperture time. We show that deviation in aperture time leads to error in the compensation. We present a way to obtain the effective aperture time experimentally.
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