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Manual_Myriam_EN_10-04-08.doc (c) SARAD GmbH
Detection thresholds and detection limits
The stated detection thresholds and detection limits are based on exposures meaning the
product of activity concentration an exposure times. All values are related to a confidence
interval of 3

.
For the correction of the Radon daughters an Equilibrium Factor F of 1.0 is assumed which is
the worst case condition.
The limits are given for the most radio-toxic nuclides Pu-239 and Sr-90 (without Y-90). The
dose coefficients (e50) of those nuclides are derived from the ICRP68 standard for inhalation
(4,7E-5 Sv/Bq (Pu-239) and 1,5E-7 Sv/Bq (Sr-90)).
We assume the breathing rate for adults defined by the EURATOM guidelines.
To calculate the detection limit/Threshold for other nuclides, following expression may be
used:
H = e(50) * Breathing Rate * Exposure.
Independent on the set integration interval, a one Minute basic interval is applied to analyse
the filter with respect to dangerous exposures:
Fig. 1 Detection Limit/Threshold (3

) for T
i
= 1 min