Detection Thresholds And Detection Limits - SARAD MyRIAM User Manual

MyRIAM - 10 -

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 = 1 min
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Manual_Myriam_EN_10-04-08.doc (c) SARAD GmbH