Dosimetry uncertainty in radiation processing

It is a fact of life that every measurement contains uncertainty. It has to be recognised and evaluated; also, it is essential that its impact on the relevant process be understood. The ISO now classifies uncertainty on the basis of how a component of uncertainty is evaluated, rather than what type of effect caused it. That changed the basic way the classification was made. This paper discusses how various uncertainty components are evaluated in dosimetry for radiation processing, as well as how combined and expanded uncertainties are obtained. In evaluating uncertainty, it is important to ensure that all the significant sources of uncertainties have been considered, and that no component of uncertainty is being considered more than once. This can be achieved by systematic procedure for evaluation. This is exemplified in the appendix where a procedure is discussed for determining various components of uncertainties associated with a specific dosimetry system and for combining these components. Possible areas of application of the uncertainty information are also discussed; these include interpretation of the measurement results as well as its impact on the radiation process. (author)