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.
These are generally produced by gravimetric dilutions of NPL standards, validated by radiometric dilution checking.
The Assigned Value for each radionuclide is calculated from the division of the standardised activity per unit mass of the original standard solution by the validated dilution factor(s). In most instances, the activities per unit mass of the radionuclides in the aqueous sample types are traceable to national standards of radioactivity, and therefore to the international measurement system.
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 and pharmaceuticals, as well as research and academia.
For specific information on determination of the assigned value and how performance is evaluated please refer to the associated NPL report. If you require more information prior to in issue of the report, contact pte@npl.co.uk.
The exercise run on an annual basis by NPL who is a UKAS accredited proficiency testing provider No. 0016
If you would like to find out how you can join the next Environmental Radioactivity PTE, please contact us via the button below.
The 2025/26 Environmental Radioactivity Proficiency Test Exercise (PTE 25/26) is now closed. If you’re not an existing customer and would like to participate in the 2026/27 exercise, please register your interest. We will add you to our mailing list and you will be invited to the upcoming exercise.
Information on the 2025/26 exercise for those participating may be found in the documents listed below.
The 2024/25 Environmental Radioactivity Proficiency Test Exercise (PTE 2023/24) is now complete and the final report has been reissued. Download reports on previous exercises.
PT item name | Description | 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 | Alpha emitters (5-100 Bq kg−1) in 500 g 2 M HNO3 (with carriers) | 243Am, 241Am, 238U, 236U, 235U,234U, and 232Th |
Beta | 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 (1-50 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 |
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