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Realization and dissemination of the units

Working Group 1.71

Realization and dissemination of the units and associated scales of acceleration, angular acceleration and derived motion quantities of solid bodies

At PTB, the units of acceleration and angular acceleration are realized using standard measuring devices (national standards) which generate and measure these motion quantities with high accuracy at sinusoidal, shock-shaped and other time-dependencies significant in practice. At present, the acceleration scale is realized in the range from 10-1 m/s² to 105 m/s²; the angular acceleration scale is realized in the range from 10-1 rad/s² to 1400 rad/s². At the same time, the units of the derived motion quantities, i.e. velocity, displacement, angular velocity and rotation angle, are realized (e.g. sinusoidal displacements at amplitudes from 1 nm to 0,5 m in the frequency range from 0,1 Hz to 50 kHz).
The units realized by standard measuring devices are disseminated to accredited and non-accredited calibration laboratories by standardized calibrations (primary calibrations in accordance with ISO 16063) of reference and transfer standards. Special transducers (e.g. quartz-based accelerometer standards with or without associated charge amplifier), ensuring high long-term stability and very small effects from the environment, are used as reference and transfer standards. Recently, special reference laser vibrometers have become commercially available which are traceable to PTB and meet the requirements of the relevant international standards (ISO 16063-11).
To make calibration of the transducers possible (to date, only accelerometers, angular accelerometers and angular velocity transducers are commercially available as standards), the standard measuring devices are combined with special computer-aided methods and techniques for voltage and charge measurements.

Different standard transducers for the dissemination of the unit of acceleration and angular acceleration

The units of acceleration and angular acceleration are disseminated not only on the national level (to DKD calibration laboratories and to non-accredited calibration laboratories of industry ) but also to the calibration services of other European countries (at present based on three agreed EUROMET projects, see Scientifico-technical co-operation).