Primary and secondary standards for radioactivity

Providing standards for more than 100 radionuclides

The NPL standards are linked to the international measurement system and provide a route to demonstrate that measurements are accurate, consistent and independent. They support regulatory compliance.

The work in this area seeks to enhance this capability, with the aim of providing standards for radionuclides that are finding new applications (for example, in nuclear medicine) and developing new measurement systems to provide additional confidence in the standards.

The work includes:

• Development of a new low-noise amplifier for the absolute counting systems, to improve the accuracy of standardisations of radionuclides that decay by electron capture
• Installation of a new instrument using the 'Triple to Double Coincidence Ratio' method to provide a method to standardise radionuclides difficult by other techniques
• A study of the mathematics of coincidence counting systems with the aim of resolving discrepancies in measurement
• Participation in the international measurement system

As radionuclide standards decay and primary standardisations are time-consuming, a range of secondary measurement equipment is needed. After calibration with a primary standard, these instruments may be used to measure or produce secondary standards that can be disseminated to users. We are developing a new current measurement system for the ionisation chambers and designing new source positioning systems for the gamma spectrometers to improve accuracy and accommodate new source constructions.

Find out more about NPL's Standard radionuclide solutions service

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