Plutonium Biokinetics in Human Body A. Luciani - Kit-Bibliothek - FZK

117 cm 3 h -1 for the incoming and outgoing flux, respectively. Therefore a difference of
pressure between the environment inside and outside of the shielded room is produced.
During the measurement the subject lays in supine position on a stretcher. The
detecting systems are assembled on their own trolleys electrically moved on tracks fixed on
the shielded room ceiling. Furthermore the trolleys are equipped with supports hosting each
detector allowing to regulate the orientation. The mobile trolley and supports allow to locate
each detecting systems over the supine subject lying on the stretcher, according to the best
geometry for each kind of measurement, e.g. lung, liver, head.
The HPGe detecting system consists of four planar n-type hyper pure Germanium
crystals thick 10 mm. Each planar detector is assembled with a 50 mm thick coaxial hyper
pure Germanium detector (see Figure 2.3.6). Both planar and coaxial detectors have a
diameter of 50 mm. A dewar of 1.5 litre assures the cooling of detectors.
Figure 2.3.6 The HPGe detecting system for direct measurements of body activity available
at the Forschungszentrum Karlsruhe.
The phoswich detecting system is composed by two detectors NaI(Tl) and CsI(Tl), 20
cm diameter, 1 and 50 mm thick respectively. The entrance window is given by a Beryllium
layer 0.25 mm thick (see Figure 2.3.7). A third detector with the same characteristics of the
aforementioned ones is added when measurements of activity deposited in head are carried
out.
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