Related Experiment Video
Updated: Jan 26, 2026

Electroretinogram Recording for Infants and Children under Anesthesia to Achieve Optimal Dark Adaptation and International Standards
Published on: September 3, 2020
Standards of radium-226: from Marie Curie to the International Committee for Radionuclide Metrology
B M Coursey1, R Collé, J S Coursey
1Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8460, USA. bert.coursey@nist.gov
Abstract:
In the early part of the 20th century, the pioneers of radioactivity research, led by Marie Curie, Ernest Rutherford and Stefan Meyer, formed a Commission internationale des étalons de radium. The Commission made arrangements for the preparation and intercomparisons of the international standards of radium, which were identified as the Paris standard and the Vienna standard. Otto Hönigschmid from Vienna prepared a first set of international secondary standards in 1912 and a second set in 1934. In both instances, these secondary standards were compared by gamma-ray measurements with the Paris and Vienna standards. The usage of these international standards of radium in the 20th century is described.
Related Concept Videos
Internal Energy
Internal Energy
Internal Receptors
Measurement: Standard Units
International System of Units
Prefixes are used to define both larger and smaller quantities in the SI system. For example, milli, micro, and nano define smaller quantities, while kilo, mega, and giga are used to define...
Radioactive Decay and Radiometric Dating

