In the context of international standards like the ISO 9000 series or ISO 17025 the traceability of measurement instruments of physical units in industrial processes gained more importance in the last two decades, so to say also for vacuum measurement. Traceable calibrations of vacuum gauges ensure agreement with the SI units. For this purpose vacuum primary standards are needed. The international system of metrology ensures that the vacuum primary standards registered in the system are equivalent and fulfil their specifications. Secondary and reference standards are used to disseminate the...
The kilogram is unique among the base SI units in being the only one defined by an artefact rather than with relation to naturally occurring physical constants. A major problem with maintaining the traceability of the mass scale is the inherent instability of the kilogram artefacts. National standard kilograms accrete surface contamination over time which leads to an increase in their mass values. Without reference to the international prototype kilogram it is difficult to assess the magnitude of this mass gain and the traceability of measurements is compromised to some extent. This...
We describe a new approach to directly link air and vacuum mass measurements. This approach uses magnetic levitation along with vacuum and balance technology to realize vacuum mass measurements. It provides direct traceability to the International Prototype Kilogram through the U.S. national prototypes without the intermediary use of vacuum artifacts. This approach will provide a direct link between the national standard of mass currently defined in air and the vacuum-based realizations founded on fundamental constants. We describe the proof-of-concept experiment, basic operation principles...
Our work concerns the mass determination of 1 kg silicon spheres in the framework of the international Avogadro project with a view to an improved definition of the kilogram. It has been shown that the original method developed by the BIPM will attain reach the uncertainty target requested by the Avogadro group. New investigations have been initiated at the BIPM using a well adapted mass comparator and more appropriate sorption transfer masses. Preliminary measurements carried out on several 1 kg silicon spheres having a natural-oxide surface are presented.
In view of the future redefinition of the kilogram, the BIPM has recently started work on a watt balance to link the kilogram with the Planck constant. This paper presents an overview of the existing experimental set-up as well as the essential ideas of the BIPM watt balance and reports the progress to date.
This paper presents the strategy followed to restore Jamaica’s Mass laboratory’s development aiming towards the expansion of its Calibration and Measurement Capabilities (CMCs). The work will present a set of key steps taken to improve the current status of the Bureau of Standards Jamaica (BSJ) Mass laboratory in order to bring the laboratory closer to a level of a recognized National Metrology Institution (NMI). The factors considered for the improvement strategy of the laboratory were: i) the laboratory’s quality system, ii) expertise and exposure of the staff, iii) work with peers NMIs,...
Manual mass comparison encumbers essentially a measurement or calibration with frequent interventions. Recently, an a5 automatic comparator (for the range of 1 mg ~ 5 g) from Mettler-Teledo (MT) has been introduced to Korea Research Institute of Standards and Science (KRISS) to ensure concretely the traceability of national standard. The stabilization time, the integration time and the number of measurements are selected as optimization parameters. The repeatability is obtained in more than 350 measurements. In the viewpoint of uncertainty, no preference condition is found from the result....
It has been proved that, under certain experimental conditions in life sciences, the mass differences in the range of units of &g can be determined by a high-sensitive measurement of radioactivity with a comparable precision as by the use of analytical balances. The advantage of determinations by radioactivity of measurements represents a further use of the obtained values in evaluation of the biological experiment.
Our aim is to establish a measurement system that enables highly accurate measuring mass and length of moving products with a relatively high speed on a conveyor belt. In this paper, effectiveness of the proposed measurement system is demonstrated by an analysis of a digital image taken by a digital camera. The advantage of using a handy digital camera is less expensiveness and convenience for processing. We gave a brief explanation of the length measurement with a digital image and discussed some technical problems in attaining length measurement with high accuracy. In this paper, we...
Quantum-weight generating cantilever devices comprising a 20 micron-sized ringshaped Niobium film deposited on the paddle of an ultrasoft single-crystalline silicon cantilever were characterized. High-quality niobium film was patterned by optical lithography and deposited using an ultra-high-vacuum sputter system within the microfabrication process of cantilevers, which adopts double-side reactive-ion-etching. The fabricated niobium film was observed using scanning electron microscope and atomic force microscope, and its superconducting property was also examined from lowtemperature...