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;
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*. These items are generally produced by gravimetric dilutions of NPL standards which are 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, Pharmaceuticals as well as research and academia.
NPL dispatches 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. Participants’ results are analysed to provide the deviation, and the associated standard uncertainty, from the assigned value. 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 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 | 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 |
The invitation to participate in the 2024/25 exercise is now closed. If you’re not an existing customer and would like to participate in the 2025/26 exercise, please register your interest at pte@npl.co.uk. We will add you to our mailing list and you will be invited to the upcoming exercise. An invitation letter announcing this exercise is planned to go out in August 2025.
Reporting is now underway for this exercise (until 30th of June, 2025). Please see documents below for more information:
Sample information & reporting
If you would like to participate or register interest for future exercises, please email pte@npl.co.uk
The 2023/24 Environmental Radioactivity Proficiency Test Exercise (PTE 2023/24) is now complete and the final report has been reissued NPL Report IR66. Please note that reports on previous exercises are also available here.
For questions, queries and comments relating to the Environmental PTE scheme please contact us.
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