MyRIAM
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Manual_Myriam_EN_10-04-08.doc
(c) SARAD GmbH
The basic interval to determine the filter activity is fixed to one Minute to realise an immediate
alert in case of very high exposure. In addition, the user may set a second integration interval
in the range of 1 to 255 Minutes. The integration interval defines the point to point distance
within the stored time distribution. A longer integration interval causes a decreased detection
limit which allows to detect a lower exposure.
If the calculated dose exceeds the user defined alert level, a audible as well as an optical
signal is activated.
Beside the online observation of the person an exact dose calculation can be performed by a
subsequent filter analysis.
The Myriam offers a special operation mode where the pump remains switched off during the
measurement. The influence of the Radon daughters will become negligible and the
detection limit may decreased as required by increasing the measurement period.
The following table gives a short overview about the detection limits with respect to the
operation conditions (assumed breathing rate of 8100 m³/a).
1 Minute basic interval
60 Minutes integration
interval
Filter analysis
12 hours
Concentration of
Po-218 [Bq/m³]
10
100
1000
10
100
1000
0
Pu-238/239 [mSv]
2.28
3.31
6.15
0.09
0.19
0.49
0.0024
U-234/238 [mSv]
0.42
0.61
1.13
0.016
0.035
0.090
0.00044
Sr-90/Y-90 [mSv]
0.020
0.043
0.109
0.0015
0.0040
0.0116
0.00001
*) The mean value of the indoor Po-218 concentration is less than 10 Bq/m³. Under special
geological conditions the level can reach 100 Bq/m³. Concentration values up to 1000 Bq/m³
are observed only inside mines, caves and sealed water supplies.