UNCERTAINTY OF MEASUREMENT AND LOWER DETECTION LIMIT OF TRACK ETCHED DETECTOR SYSTEMS - EXPERIMENTAL-VERIFICATION AND CONSEQUENCES FOR INTERCOMPARISON EXPERIMENTS

Instead of using three times the empirical standard deviation. s0, of the background density, this approach makes use of the random uncertai nty of measurement relative to track density and the definition of the lower limit of detection, H(LLD). In addition to s0 values, this take s into account (a) the corresponding single counting areas of the back ground detectors, (b) the total counting area of the background as wel l as field detectors used for the actual measurement of the quantity o f interest, (c) the desired confidence level, and (d) the response of the detector for the quantity of interest. In agreement with experimen tal results the s value also includes contributions from systematic un certainties. In order to reduce the H(LLD) value of an etched track de tector system, the so-called 'counting factor' introduced here may be used to optimise the number of background and field detectors. The 'de tector quality factor' was found to provide a quantitative criterion f or the quality control of CR-39 systems. This approach was utilised fo r the Eurados-Cendos Intercomparison 1990 of different CR-39 systems. The H(LLD) values used here for a normalised counting area of 1 cm2 im prove the comparison of systems and are recommended for future interco mparisons. In addition, the coefficient of variation relative to neutr on dose is presented for typical KfK systems using CR-39 and Makrofol plastics.