8 MN1007-C
3 Operational Options
The Tracerco NORM Monitor-IS has been designed to provide a versatile instrument which will enable the
operator to confidently detect and quantify contamination arising from NORM under most environmental conditions.
In order to achieve this versatility, the instrument is provided as a single data processing unit with the choice of two
types of radiation detection probes.
To realise the full capability of the instrument, it is important that the operator understands the technical
advantages of each probe and the circumstances under which they should be deployed.
3.1 Probe Selection
Although, in general terms, both the Geiger Müller (GM) and Scintillator-based probes will detect the presence of
NORM under most environmental conditions, there can be significant variations in detection sensitivity for different
scale types.
The following table provides guidance on the selection of probe for a particular NORM measurement application.
The table has been compiled on the basis that environmental background radiation is comparable to that found in
an offshore facility and there are no local abnormal circumstances – for example, the presence of local scale
storage containers will affect the detection capability of the scintillation probe due to a higher background radiation
reading.
This guidance is based on monitoring experience and the known technical characteristics of each probe. The
operator should always observe local operating procedures and, where appropriate, seek confirmation from the
appointed RPS or RPA.
Table 2 – Measurement options for probes
Type of measurement Suggested probe
Technology Tracerco part
ref.
Radium scale with readily accessible dry surface Geiger Müller SA-49
Radium scale with significant water, oil or sludge deposition Scintillator SA-50
Radium scale contaminated tubulars < 4” diameter (100mm) Scintillator SA-50
Radium scale deposition using external pipe surface survey
measurements
Scintillator SA-50
Lead-210 scale with readily accessible surface ( wet or dry) Geiger Müller SA-49
3.1.1 Geiger Müller End Window (Pancake) Probe
The Geiger Müller probe utilises a thin window detector which, although capable of detecting gamma radiation, is
particularly sensitive to the surface measurement of alpha and beta radiation.
The Geiger Müller probe’s high sensitivity to alpha and beta is ideally suited to the measurement of lead-210 and
polonium-210 which are commonly found in gas producing facilities where NORM is transported in the form of the
gas radon-222.
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General