Investigation of the uncertainty contributions of the alignment of PTB’s double-ended interferometer by virtual experiments

High-accuracy length measurements of prismatic bodies (e.g. gauge blocks) are usually performed by means of single-ended interferometers. To perform these measurements, the gauge block must be wrung to a reference plate. The quality of contact affects the measured length and also the wringing process wears down or damages the measuring faces. Furthermore, it limits the use of such interferometers to bodies that are suitable for wringing. PTB’s double-ended interferometer allows high-accuracy length measurements that are traceable to the International System of…

Development of a new KRISS low frost-point generator with improved uncertainty from 7 nmol·mol −1 to 1000 nmol·mol −1

A new saturator-based low frost-point generator (LFPG 2) is developed at the Korea Research Institute of Standards and Science (KRISS), and its uncertainty is evaluated from 7 nmol·mol −1 to 1000 nmol·mol −1 in nitrogen. The humidity generator operates in the two-temperature two-pressure mode to achieve target water vapor concentrations. First, the apparatus of the generator and the operation procedures, including purging mode and generation mode, are introduced in depth. Then, all uncertainty factors that affect trace-moisture generations are analyzed using a…

On-site comparison of Quantum Hall Effect resistance standards of the NMC A*STAR and the BIPM: Ongoing key comparison BIPM.EM-K12

The ongoing on-site comparison BIPM.EM-K12 is part of the BIPM programme implemented to verify the international coherence of the primary resistance standards. It allows National Metrology Institutes (NMIs) to validate their implementations of the Quantum Hall Effect (QHE) for dc resistance traceability by comparison to the reference maintained at the BIPM. The realization of the ohm from the QHE-based standard of the NMIs at 100 Ω is compared with that realized by the BIPM from its own transportable quantum Hall resistance…

Update of the BIPM comparison BIPM.RI(II)-K1.Co-60 of activity measurements of the radionuclide 60 Co to include the 2019 result of the VNIIM (Russian Federation)

Since 1976, 29 laboratories have submitted 73 samples of 60 Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Co-60. Recently, the VNIIM (Russian Federation) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a…

Temperature dependence of effective area and depth of extrapolation chamber in dosimetry

The variation of the effective area and zero-offset of an extrapolation chamber used for beta-ray and low-energy x-ray dosimetry was measured as a function of temperature in the range 19 °C to 25 °C. The effective area and zero-offset were determined from the capacitance of the extrapolation chamber measured with the chamber depths in the range up to 1.4 mm. The extrapolation chamber was put in a precision thermostatic air bath with a programmable temperature regulator to evaluate the influence of temperature…

Final report on the CIPM key comparison CCAUV.V-K5

The results of the fifth CIPM key comparison (KC) in the area of vibration, here concerning sinusoidal acceleration, are presented. This comparison was intended to build the foundation for subsequent regional key comparisons over the extended frequency range from 10 Hz to 20 kHz. Measurement results reported by 14 participants for magnitude and phase shift of complex charge sensitivity of single ended and back-to-back accelerometers were compared. A key comparison reference value has been defined for each type of artifact, and…

Precise measurement of the thickness of silicon wafers by double-sided interferometer and bilateral comparison

The Length Standards Group at the National Metrology Institute of Japan has developed a double-sided interferometer (DSI) for non-contact thickness measurement, that is traceable to SI units. The measurement uncertainty of DSI was evaluated. The results of gauge block measurements were compared with those of a conventional gauge block interferometer and their equivalency within the claimed uncertainty was confirmed. The advantage of applying a DSI in measuring the thickness of silicon wafers is that it has absolute measurement traceable to SI…

Final report of the new BIPM comparison BIPM.RI(II)-K1.Ac-225 of activity measurements of the radionuclide 225 Ac to include the 2019 result of the PTB (Germany)

In 2019, the PTB(Germany) has submitted a sample of 225 Ac to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ac-225. As PTB is the first participant in the comparison no key comparison reference value (KCRV) and no degrees of equivalence can be calculated. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the…

Report on the SIM photometry and radiometry Key comparison of spectral regular transmittance

This report details the results of the Inter-American Metrology System (SIM) key comparison on regular spectral transmittance (SIM.PR-K6.2010). Eight national metrology institutes participated in the comparison, which covered the spectral range from 380 nm to 1000 nm and the nominal transmittance range from 0.1 % to 90 % transmittance. The protocol mirrored that of the key comparison conducted by the Consultative Committee on Photometry and Radiometry (CCPR-K6.2010). The National Institute of Standards and Technology (NIST) served as the pilot. Each participant…

Update of the BIPM comparison BIPM.RI(II)-K1.Ga-67 of activity measurements of the radionuclide 67 Ga to include the 2010 result of the PTB (Germany) and the 2010 result of the NIST (United States)

Since 1978, 10 laboratories have submitted 17 samples of 67 Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. The PTB (Germany) and the NIST (United States) participated in the comparison. The key comparison reference value (KCRV) has been re-calculated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are…