National Physical Laboratory

Standardised solutions of isotopically pure radionuclides

At or near the working level for use by laboratories making measurements of environmental radioactivity.

NPL environmental radioactivity standards
NPL environmental radioactivity standards

NPL supplies a range of over twenty different radionuclides for use as chemical yield tracers (e.g. in radiochemical separations and alpha spectrometry) and calibration of various detector systems such as liquid scintillation counters and sodium iodide gamma-detectors.

NPL also supplies a mixed radionuclide standard solution for the calibration of hyperpure germanium gamma spectrometers. This 'mix' is supplied at two activity levels (1 kBq g-1 and 10 kBq g-1) and fresh batches are issued annually in April.

For further information on the NPL mixed nuclide, please download the listing: Mixed Radionuclide Standard Solutions Adobe Acrobat PDF file

Advantages of using low-activity standardised solutions

  • Activity handled is minimised to comply with the Ionising Radiations Regulations
  • Standards are at or near the working level
  • Minimal dilution and handling required, resulting in improved accuracy of measurement
  • Reduced risk of contaminating low-background instruments
  • The solutions are dispensed from bulk solutions traceable via verified dilutions to measurements of individual radionuclide solutions (carried out using either the techniques used in primary standardisations or a transfer instrument previously calibrated using a primary standard)
  • The solutions are supplied in flame sealed glass ampoules of type Q as described in BS 795:1983

Details provided on Certificate of Calibration

  • Activity per gram of solution
  • Reference time
  • Activity of any impurity radionuclides present
  • Measurement uncertainty
  • Chemical form

The activities shown in the Product Listing are nominal values stated at the time of dispensing. The activity at the time of dispatch will depend on the dispensing date and the half-life of the radionuclide.

Download the Product Listing Adobe Acrobat PDF file

Subject to availability, we aim to deliver your standards to you within four weeks of receipt of your order (except 'special orders', e.g. Mixed Nuclide and Organically Bound Tritium).


Customer Service tel: +44 20 8943 8695

Last Updated: 26 Jan 2018
Created: 7 Feb 2011


Please note that the information will not be divulged to third parties, or used without your permission