Measurement for our planet
Measurement for our planet

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Radioactivity services

Environmental radioactivity proficiency test exercise

For laboratories measuring radioactivity

What is the Environmental Radioactivity Proficiency Test Exercise?

Proficiency Testing assesses a laboratory’s performance at carrying out a measurement. Regular Proficiency Testing provides evidence of the quality of a laboratory’s measurement capabilities. Accreditation bodies consider participation in Proficiency Testing a demonstration of a laboratory’s commitment to quality. Proficiency testing also provides an opportunity to:

  • Test, validate and compare measurement schemes;
  • Evaluate performance characteristics of a method;
  • Provide confidence to customers in the quality of results;
  • Identify measurement issues and improve overall accuracy;

NPL produces a range of proficiency test items. Recent exercises have included aqueous samples containing a mixture of alpha, beta, and gamma emitters at activity concentration relevant to environmental applications*. NPL is also working towards producing solid matrixes; assigned values may be based on a consensus value or be assigned by NPL. Laboratories choose which sample types apply to their measurement capabilities. Participants in the exercise are from various industries including, Construction, Nuclear, Radiation protection, Pharmaceuticals as well as Research and Academia.

NPL despatches the proficiency test items to participants, who have approximately four months to measure them and submit the results to us. NPL compiles an anonymised exercise report and provides feedback to the laboratories on their performance. The exercise is accredited to ISO 17043 and run on an annual basis by NPL.

If you would like to find out how you can join the next Environmental PTE, please contact us via the button below.

PT Item Name


Example radionuclides

Alpha Beta

Alpha and Beta emitters (1-20 Bq g−1) in 20 g 2 M HNO3 (with carriers)

3H, 63Ni, 90Sr, 239Pu, 241Am, and 244Cm


Alpha emitters (1-20 Bq kg−1) in 500 g 2 M HNO3 (with carriers)

243Am, 241Am, 238U, 236U, 235U,234U, and 232Th


Beta emitters (0.1-2 Bq g−1) in 500 g 0.01 M NaOH (with carriers)

3H, 14C, 36Cl, 99Tc, and 129I

Gamma High

Gamma emitters (1-25 Bq g−1) in 100 g 1 M HNO3 (with carriers)

54Mn, 60Co, 65Zn, 133Ba, 134Cs, 137Cs, and 154Eu

Gamma Low

Gamma emitters (1-50 Bq kg−1) in 100 g 1 M HNO3 (with carriers)

60Co, 85Sr, 134Cs, 137Cs, 210Pb, and241Am

How to Participate

Upcoming exercise (2021)

An invitation letter for the 2021 exercise has been circulated to past participants and those who have registered their interest. Participation for this exercise is now closed. If you would like to register interest for future exercises please email

Current exercise

The 2020 Environmental Radioactivity Proficiency Test Exercise (PTE 2020) is now underway with the report due to be issued in October (2021). The submission deadline for results has now passed.

The results for the 2020 exercise are due to be discussed during CARM 2021 (November 2021).

Past exercise and reports

The 2019 Environmental Radioactivity Proficiency Test Exercise (PTE 2019) is now complete and the final report has been reissued NPL Report IR57. Please note that reports on previous exercises are also available.

For questions, queries and comments relating to the Environmental PTE scheme please contact us. 


NPL also provide radioactive standards, calibrations and consultation. For information related to this or discuss your requirements please contact us

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Find out more about our Standard radionuclide solutions

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