15 Jul 2014

Improvement of uncertainty measurements in nuclear forensics

Improvement of uncertainty measurements in nuclear forensics

© EU, 2014

Age dating is used in nuclear forensics to determine the elapsed time since a nuclear material has been processed and separated from its daughter nuclides.

This is important information to characterise intercepted nuclear material and establish its origin, identify perpetrators and their network as well as providing evidence to bring them to justice. Given the severity of such activities, it is imperative that all parts of the forensic analysis comply with accepted norms for the presentation of scientific evidence. Uncertainty formulae are essential to assess the level of accuracy of the measurements, so as to avoid overly optimistic confidence levels that may lead to potentially erroneous conclusions.

Scientists from the JRC-Institute for Reference Materials and Measurements (IRMM) demonstrated  that there is a need for better half-life data, more traceability in establishing their uncertainties and more harmonisation in the selection of reference data among scientific communities. As the derivation of the uncertainty formulae for age measurements is a difficult task, JRC scientists presented solutions, approximations, graphical representations and interpretation thereof on typical nuclides such as actinides in the context of non-proliferation commitments. It became apparent that half-life uncertainties are often underestimated, which may lead to erroneous conclusions in forensic investigations.

The JRC continues to contribute to the reliability of radioactivity measurements by e.g. establishing the SI-unit becquerel through primary standardisations at the highest precision, measuring reference decay data that are indispensable in various applications, developing new methods, producing and characterising reference materials, organising proficiency tests and producing certified nuclear reference materials. These tools will make nuclear forensics more reliable.

Read more in: S. Pommé, S.M. Jerome, C. Venchiarutti, Uncertainty propagation in nuclear forensics, Appl. Radiat. Isot. (2014) 89:58–64, doi:10.1016/j.apradiso.2014.02.005

JRC Institutes