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For the quantitative surface characterization of a monocrystalline silicon sphere PTB has constructed and taken into operation an analytical instrumentation, which combines X-ray fluorescence and X-ray photoelectron spectroscopy techniques. The main objective of this novel instrumentation is the characterization of the oxide layer and unintentional contaminations, e.g. from hydrocarbons. It is equipped...
This paper describes a technique for digitally calibrating an ac signal against another one taken as reference, which is not obligatorily of the same frequency as the first. The requirements of this technique are: knowledge of the spectrum of the ac reference signal, coherent generation of the signals with respect to a single time-base, a well-known bandwidth characteristic of a digitizer over frequency,...
A method has been proposed to calibrate the linearity errors of wideband digitizer at frequencies up to 100 kHz. The method is based on the use of self-calibrated inductive voltage divider with ratio of 2n:1. The linearity errors in phase angle and amplitude of two channels of the digitizer have been calibrated against 1 V. The measurement has been done at the input voltage ranges from 1 V down to...
The paper presents the development of a 35 kV fully-insulated two-stage voltage transformer(TSVT), and its applications by connecting in series with another 35 kV semi-insulated TSVT to determine the voltage dependence(VD) of a 110 kV TSVT. The result showed the VD of the 110 kV TSVT is around −1.6×10−6 and +1.6 μrad in magnitude and phase, respectively.
This work describes a measuring set-up which allows the comparison between measurements of electromagnetic fields inside a suitable phantom and the same quantities computed numerically. The aim is to quantify the overall reliability and accuracy of dosimetry approaches at frequencies in use in Magnetic Resonance Imaging. Numerical results were obtained through four common techniques used for electromagnetic...
This paper describes a resistance transfer system based on resistance transfer devices. Authors developed a single path resistance transfer system and tested it in the Central Office of Measures in Poland. Although the system was useful it had some disadvantages, such as the lack of temperature stabilization of secondary standards, voltage influence, resistance unit transfer from the primary standard...
In research and industry, the determination of material parameters plays an important role. One of these parameters is the electrical conductivity σ. In metallic materials, it allows the purity of the raw metal and the correct composition of alloys to be checked. Due to increasing demand, PTB has decided to establish calibration facilities for semiconducting material. The measurement set-up and the...
This paper describes the characterization of high resolution analog-to-digital converters using a programmable Josephson voltage standard at frequencies well above the kilohertz. The basic idea is to use an equivalent time sampling algorithm to overcome the limited sampling frequencies of the analog-to-digital converter under test.
A two-channel digital sampling system for estimating harmonic parameters at low frequencies, which utilizes two integrating digital sampling voltmeters in a master-slave configuration, was developed at Centro Nacional de Metrología de Panamá (CENAMEP AIP). A bilateral study was then conducted between Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro) and CENAMEP AIP to compare the...
This paper describes the signal processing algorithms that can be used for the PMUs operating in a dynamic environment. Dynamic response and rejection to noise, harmonics and interharmonics are discussed and some solutions for improving them, emerging from the technical literature and from some additional tests, are proposed. For example dynamic response can be improved by evaluating the Taylor series...
In this paper, a proposal to reduce the influence of stray capacitances and non-linear effects on resistors used for voltage dividers up to 1000 V and 100 kHz is presented. A novel type of shield is proposed which avoids the use of guarding arms.
This paper is oriented towards comparison of measurement methods for iodine absorption cells quality evaluation. Traditionally used method of laser induced fluorescence with evaluation of Stern-Volmer coefficients and method of measurement of absolute frequency shifts of hyperfine spectras have several limitations and sensitivity limits. Due to this reason an alternative technique of hyperfine spectra...
NICT has commenced development of an accurate and stable frequency standard for THz frequency band. We succeeded in phase-locking a single-mode 3THz quantum cascade laser (THz-QCL) to a THz reference. Using the phase-locked THz-QCL and a hot electron bolometer mixer, a THz wave generated by photomixing was evaluated. The result showed that the phase-locked THz-QCL and the optically generated THz wave...
Precision measurement of photon pressure by various methods has been ongoing for over a century, but without a metrological comparison between optical power and mass or force standards. The work summarized herein describes metrological methods for use of radiation pressure forces to interconvert between mass, force and laser power. These experiments have the potential to allow the accurate measurement...
It has been proved that quantum coherence effects in highly-excited Rydberg atoms could provide a revolutionary solution for RF field measurement. A two-photon transition due to interaction of RF electric field with cesium Rydberg atoms will be discussed. RF E-field whose carrier frequency satisfies a two-photon transition can induce an Autler-Townes splitting within electromagnetically induced transparency...
This paper describes the carrier-phase two-way satellite time and frequency transfer experiment performed between the metrology institutes PTB (Braunschweig) and LNE-SYRTE/OP (Paris) using ground stations equipped with dedicated modem equipment developed by NICT. The frequency instability of the PTB-OP link reached 4×10−16 at 1 day, a performance of about one order of magnitude better than that obtained...
We have developed a new low pressure sensor which is based on the measurement of (nitrogen) gas refractivity inside a Fabry-Perot (FP) cavity. We compare pressure determinations via this laser refractometer to that of well-established ultrasonic manometers throughout the range 100Pa to 100000Pa. The refractometer demonstrates 10−6 precision for p > 50 kPa; — as good or better than the manometer...
We have characterized AC performance of a high-stability AC source using AC-programmable Josephson voltage standard system (AC-PJVS) with a maximum root-mean squared (rms) output of 10 V. A differential sampling method is used for characterizing the performance of the AC source. Our AC voltage measurement shows that the stability of the AC source over a day is less than 1 μV/V, and the deviation from...
In this paper two multiport calibration schemes for vector network analyzer (VNA) characterization, including port-to-port and full multiport procedures, are compared with regard to underlying error models and measurement results. Test measurements have been performed, using a 4-port VNA. As device under test (DUT), a 3-port power splitter was employed, with the remaining VNA test-port being short-circuited...
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