The irony of the magnet system for Kibble balances—a review

The magnet system is an essential component of the Kibble balance, a device that is used to realize the unit of mass. It is the source of the magnetic flux, and its importance is captured in the geometric factor Bl . Ironically, the Bl factor cancels out and does not appear in the final Kibble equation. Nevertheless, care must be taken to design and build the magnet system because the cancellation is perfect only if the Bl is the same in…

Achievement of 0.005% combined transfer uncertainties in the NIST detector calibration facility

Improvements in a lamp-monochromator-based facility at the National Institute of Standards and Technology (NIST), the Visible near-infrared Spectral Comparator Facility (VisSCF) which is used to calibrate optical detectors for spectral radiant power responsivity from 300 nm to 1100 nm, are described. These changes include extending the VisSCF operational range down to 300 nm from 350 nm, thereby fully covering the ultraviolet-A (UVA) spectral region and partially covering the UVB range. These improvements have lowered the magnitudes of most of the components in the uncertainty budget…

Spectral irradiance scale realization and uncertainty analysis based on a 14 mm diameter WC–C fixed point blackbody from 250 nm to 2500 nm

Spectral irradiance scale in the wavelength range from 250 nm to 2500 nm was realized at National Institute of Metrology on the basis of a large area tungsten carbide–carbon (WC–C) high temperature fixed point blackbody, which is composed of a 14 mm diameter WC–C fixed point cell and a variable temperature blackbody BB3500MP as a furnace. A series of 1000 W FEL tungsten halogen lamps were used as transfer standards. The new spectral irradiance scale was compared with the scale based on a variable-temperature blackbody…

Differential sampling of AC waveforms based on a programmable Josephson voltage standard using a high-precision sampler

A high-precision sampler, Fluke 8588A multimeter in the sampling mode, was utilised to perform differential sampling of AC waveforms with a programmable Josephson voltage standard. The systematic error on the differential sampling, induced by the inherent voltage-response characteristics and built-in low-pass filter of the sampler, was estimated. Experimental results and numerical simulations revealed that the sampler could be used for reliable differential sampling of AC waveforms at frequencies up to several kilohertz, with an appropriate number of the voltage steps per…

News from the BIPM laboratories—2021

In order to fulfil its mission to ensure and promote the global comparability of measurements, the BIPM operates laboratories in the fields of physical metrology, time, ionizing radiation and chemistry. These laboratories act as centres for scientific and technical collaboration between Member States providing capabilities for international measurement comparisons on a shared cost basis. They coordinate international comparisons of national measurement standards agreed to be of the highest priority, and they establish and maintain appropriate reference standards for use as the…

Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the NRC, Canada and the BIPM in 60 Co gamma radiation

A new key comparison of the standards for air kerma of the National Research Council of Canada (NRC), Canada and the Bureau International des Poids et Mesures (BIPM) was carried out in the 60 Co radiation beam of the BIPM in October 2020. The comparison result, based on the calibration coefficients for three transfer chambers and expressed as a ratio of the NRC and the BIPM standards for air kerma, is 1.0022 with a combined standard uncertainty of 2.2 parts in…

Key comparison BIPM.RI(I)-K4 of the absorbed dose to water standards of the NRC, Canada and the BIPM in 60 Co gamma radiation

A new key comparison of the standards for absorbed dose to water of the National Research Council of Canada (NRC), Canada and the Bureau International des Poids et Mesures (BIPM) was carried out in the 60 Co radiation beam of the BIPM in October 2020. The comparison result, based on the calibration coefficients for three transfer standards and evaluated as a ratio of the NRC and the BIPM standards for absorbed dose to water, is 0.9995 with a combined standard uncertainty…

PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody – Part 1

Under the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM). Eleven Metrology Institutes or Designated Institutes and the BIPM participated in the first phase of the pilot study (Part 1). The purpose of this pilot study was to develop measurement capabilities for…

Report on the AFRIMETS.M. F-S1 supplementary force comparison for 10 kN and 100 kN

This bilateral comparison of Force Standard Machines (FSM) named AFRIMETS.M. F-S1 was carried out in the force range from 1 kN to 100 kN between Physikalisch-Technische Bundesanstalt (PTB) of Germany as the pilot laboratory and Kenya Bureau of Standards (KEBS) of Kenya as the participant laboratory. KEBS had already participated in the APMP.M. F-K2 key comparison where measurements were made only at 50 kN and 100 kN force steps. Therefore, this bilateral comparison was planned to thoroughly compare the KEBS FSM…

A comparison in conventional mass measurements SIM.M.M-S6

The present document reports the results of a bilateral comparison in the calibration of mass standards that was carried out between CESMEC (Chile) and CENAMEP AIP (Panamá). This comparison was carried out in the following nominal values: 200 mg, 1 g, 50 g, 200 g, 1 kg, 2 kg, and 10 kg. 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 BIPM key comparison database…