The Temperature Laboratory at TUBITAK UME initiated a study which focused on the construction of freezing point cells of ITS-90 as primary temperature standards. The first cell constructed within the ...scope of this study was an open tin freezing point cell and the results were in good agreement with the reference tin fixed point cell of UME. The second set of cells constructed was two open zinc freezing point cells. The design of these cells is similar to the tin freezing point cell. After construction, all the home-made cells were evaluated by analyzing their melting and freezing curves. Finally comparison measurements were performed between the current laboratory reference zinc cell and all newly constructed cells.
First, concepts to state compliance with specifications are presented when taking into account the uncertainty of measurement. Then, the methods used by accredited calibration laboratories, ...especially within the Deutscher Kalibrierdienst (DKD), are introduced and compared with these methods and concepts. Compliance can only be stated with some probability (risk), which can be calculated by integration, if the measurement results and its probability density functions are known. A scheme for the calculation of the risks by the Monte Carlo method leads to zones of correct and false acceptance, and correct and false rejection. The user of the device under test or calibration has to decide which risk is acceptable. A statement of compliance should only be made if the measurement capability index is not smaller than about 2. The correspondence of probabilities of compliance and guard bands is shown. The rules of ISO 14253-1 and DKD-5 are equivalent to the usage of a guard band of special width. Finally, the performance criteria for comparisons in calibration are treated briefly. Their use has some similarity to the decisions made on compliance.
The lightning impulse voltage calibrators, developed at National Measurement Laboratory (NML) and MIKES-HUT, and a recently developed commercial digitizer were compared. With this three-way ...comparison, not only the accuracies of the devices were compared, but also the linearity of measurement of both peak voltage and time parameters was investigated. The results demonstrated that the linearity of the calibrators is superior to that of the digitizer.
Comparison measurements on reference standards are reported in which 13 partners with different instruments took part. A set of prototype standards which had been produced and calibrated within a ...European project were used for the measurements. Here, results of measurements on a 240
nm step height standard and a two-dimensional lateral standard with a nominal pitch of 1
μm are reported.
Accurate measurement of individual short-lived radon progeny concentrations is very important for dose evaluation and related researches taking radon progeny as radioactive tracers. Different methods ...have been developed, but higher methodological sensitivity is needed for field measurement under the limitation of size, weight and power consumption of the instrument. For the purpose of developing new measurement method with higher sensitivity, an optimized method based on alpha spectrometry following the Wicke method (Wicke, 1979) is demonstrated, which shortens the measurement cycle to 60 min and make it more suitable for field measurement. For comparison, a series of verification experiments were carried out, and the methodological sensitivity and uncertainty were analyzed in detail in this paper. Results show that the optimized Wicke method can give accurate individual radon progeny concentrations and equilibrium equivalent concentration (EEC) in different environments. The deviation between EEC measured by the optimized Wicke method and the original Wicke method is less than ±2.9%, and the deviation between the optimized Wicke method and the Kerr method is less than ±3.9% in different environment. The methodological sensitivity of the optimized Wicke method is nearly the same as the original method with a much shorter measurement cycle, and 4.3 times higher than that of the Kerr method, which lowers the measurement uncertainty especially in the actual environment.
●An optimized method for hourly individual radon progeny measurement●High methodological sensitivity and low measurement uncertainty●Performance of comparison experiments in different radon progeny concentration levels
A calibration scheme for making oceanographic thermometers traceable to the International Temperature Scale of 1990 (ITS-90) in the range from 1 °C to 32.5 °C was established. The calibration scheme ...involves two phases: a first phase, in which a working reference thermometer is calibrated by comparison against an ITS-90 traceable standard platinum resistance thermometer (SPRT) in a commercial water bath, and a second phase, in which up to 24 oceanographic thermometers are simultaneously calibrated against the calibrated working reference thermometer in an ad hoc previously developed water bath. Finally, an uncertainty budget was made for both calibration phases and resulted in 1.5 mK and 3.5 mK for the first and the second phases, respectively, which satisfy the requirements of the oceanographic community for the accurate monitoring of ocean temperature.
This paper considers the unknown electrical resistance (measurand) as the numerical result of the measurement that was carried out by means of the well-known direct comparison measurement method ...using an appropriate standard resistor and voltmeter. In the literature, this measurement method is also referred to as a series comparison method. This method of measurement is one of the indirect methods and is suitable for measuring low resistance. This paper presents two approaches for evaluating the unknown electrical resistance and its associated combined standard uncertainty. The entire process of evaluating the combined standard uncertainty that is associated with the measurand and the standard uncertainties that are associated with the analyzed input quantities has been entirely performed in accordance with the applicable international recommendations and guidelines for the uncertainty of measurement. The analyzed approaches for evaluating the combined standard uncertainty are designed to be universal and valid both for the mutually non-correlated input quantities and for the mutually correlated input quantities, which can be obtained from a single observation, or repeated observations or by other means. This paper can substantially contribute to the measurements in electrical engineering and education.
PDF
