When the model doesn't cover reality: examples from radionuclide metrology

It could be argued that activity measurements of radioactive substances should be under statistical control, considering that the measurand is unambiguously defined, the radioactive decay processes are theoretically well understood and the measurement function can be derived from physical principles. However, comparisons invariably show a level of discrepancy among activity standardisation results that exceeds expectation from uncertainty evaluations. Also decay characteristics of radionuclides determined from different experiments show unexpected inconsistencies. Arguably, the problem lies mainly in incomplete uncertainty assessment. Of the various reasons leading to incomplete uncertainty assessment, from human failure to limitations to the state-of-the-art knowledge, a selection of cases is discussed in which imperfections in the modelling of the measurement process can lead to unexpectedly large underestimations of uncertainty.

POMME Stefaan; 

2016-02-08

IOP PUBLISHING LTD

JRC98006

0026-1394,   

http://iopscience.iop.org/article/10.1088/0026-1394/53/2/S55,    https://publications.jrc.ec.europa.eu/repository/handle/JRC98006,   

10.1088/0026-1394/53/2/S55,