A new definition of the kilogram was necessary, in order to ensure the measurement unit is independent from a physical object. more
Traceability with Microgram Weights
Advances in nanotechnology and biotechnology are driving the need for traceable small-force measurement in the sub-milligram measurement range. To meet this demand, reproducible microgram weights issued with a calibration certificate have created critical traceability to the International Prototype Kilogram (IPK) and thus to the International System of Units (SI). The key factors for design and development of microgram weights - material, shape, handling and robust production processes - are explained. The UK National Measurement Office (NMO) describes the challenges and procedures involved in becoming the first accredited microgram weight calibration laboratory in the world. Calibration methods and stability of microgram weights over the mid-term are also presented.