DIN IEC/TR 62461:2015-07

The saying "a measurement value without stating its uncertainty is a lie" certainly has a true core. By specifying various decimal places a precision is suggested which is not available at all. On the other hand, two different measurement values of the same size may well be correct, although the measured values differ. On the other hand, two different readings of the same size may well be correct, although the measured values differ. Therefore, the uncertainty determination according to ISO IEC Guide to the Expression of Uncertainty in Measurement (GUM) in DIN EN and DIN IEC standards compiled under VDE 0492 and VDE 0493 is required for radiation protection dosimeters and other radiation protection measuring instruments to support the application of GUM. The purpose of this VDE Guide is to support the application of GUM. At first the principle of GUM is presented based on a very simple but concrete case. Multiple examples are given in five annexes. Each annex concentrates on one type of measuring instrument which complies with an IEC product standard. In the first example of each annex the overall measurement uncertainty of a measuring instrument which only just meet all minimum requirements of the product standard. In a second example the uncertainty is determined by the application of additional information for an actual measurement. The five annexes refer to the following types of measurement instruments: - direct reading active photon and beta area dose meters according to IEC 60846-1:2009, - passive photon and beta personal dose meters according to IEC 62387:2012, - direct reading active neutron area dose meters according to IEC 61005:2003, - direct reading active radon measuring measurements according to standards of the IEC 61577, - direct reading active surface contamination meters according to IEC 60325:2002. With respect to the 2007 edition of Supplement 2 to DIN VDE 0493 replaced by this VDE guideline, the VDE guideline contains in addition to the analytical method for determination of the uncertainty the Monte-Carlo method according to Supplement 1 to GUM. Detailed information is given when which of both methods shall be applied. Finally a very simple method has been added for the decision if a measurement result differs significantly from zero or not. This method is based on DIN ISO 11929:2011 "Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Guideline to applications". The responsible committee is DKE/GUK 967.3 "Strahlenschutzdosimeter" ("Radiation protection devices") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.