Myriam; How To Apply The Myriam; Theory Of Operation - SARAD MyRIAM User Manual

MyRIAM

MyRIAM
The Myriam (My Radioactivity In Air Monitor) is a personal dosimeter to determine dose
obtained by long living radioactive dust (LLRD) within the breathed air. Both, alpha and beta
radiation will be detected simultaneously. The instrument was designed to warn persons
immediately in case of accidents or disasters as well as to provide routinely radiation
protection

How to apply the Myriam

At the begin of an observation period (e.g. at the begin of each month)
Inserting a new filter

Checking the pump flow rate

Setting the integration interval with respect to the required detection limit and

response time
If the person enters the controlled area
Starting the measurement using the „Sampling Mode".

The instrument has to be worn with open face sampling

aperture (for example at the belt)
In case of increased exposure the instrument will give an

optical as well as an audible signal
If the person leaves the controlled area
Stopping the measurement and reading/saving the

acquired data
 Recharging the internal batteries if necessary
At the end of an observation period
Starting the measurement using the „Filter Analysis

Mode" to determine the exposure/dose as exactly as required
Stopping the measurement and reading/saving the acquired data

Data analysis and archiving of the filter for preservation of evidence.


Theory of operation

The air is sucked through a filter by an internal pump whereby the radioactive aerosols will
be collected at surface of the filter. A semiconductor detector is placed directly above the
filter to determine simultaneously the collected activity.
The short living Radon daughter products within the air will be separated by alpha
spectroscopy to be not included in the exposure/dose calculation.
Because the exposure period is much less than the half life of the collected LLRD, a direct
proportionality between the filter activity and the exposure/dose is given.
The dose can be calculated by the exposure using the nuclide specific dose coefficients and
the breathing rate of the person under control.
Dose = Exposure * Breathing Rate * Dose Coefficient
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