BERTHOLD TECHNOLOGIES Uni-Probe LB 490, User Manual

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38477BA2B
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1 System Description Volume 2
1.4
Measuring Arrangements
To be able to cover a certain measuring range continuously, a mea-
suring arrangement must be realized where the dimensions of
source and detector form a geometry, which covers a measuring
field of equal size. The different options that are available will be
described below.
Which of these arrangements is chosen depends on the size of the
measuring range and on the measuring geometry resulting from
the measuring task. Moreover, constructional circumstances and
customer-specific requirements may have an effect on the device
selection.
The respective selections are made during the planning stage and
must be observed during assembly and commissioning.
The following scintillator types are available for the level gauge
Uni-Probe LB 490:
1) KS = collimator with radiation window radial
KA = collimator with radiation window axial
1.4.1 Rod Source Arrangement
Figure 1-5 shows a basic arrangement with rod-shaped source and
point-shaped detector , as well as the respective characteristic
curve. The length of the rod source is adapted to the size of the
required measuring range. The non-linearities resulting from the
measuring geometry and the dissemination and absorption condi-
tions of the radiation are compensated for by means of a non-linear
activity distribution along the rod source, including the critical zone
around the bottom end of the measuring range.
Thus, the intensity changes at the detector are already in linear
proportion to the level changes. The evaluation electronics can
work linear. Electronic linearization is not required. Therefore, it is
much easier to take the level gauging system into operation or to
replace devices.
ID no. Size Description
38477-X1X, 47678-X1X, 500XX-X1X 50x50mm NaI Point detector (KS)
1
38477-X2X, 47678-X2X, 500XX-X2X 50x50mm NaI Point detector (KA)
1
38477-X3X, 47678-X3X, 500XX-X3X 500mm plastic Rod detector
38477-X5X, 47678-X5X, 500XX-X5X 1000mm plastic
38477-X7X, 47678-X7X, 500XX-X7X 1500mm plastic
38477-X9X, 47678-X9X, 500XX-X9X 2000mm plastic
53214-XXX 150x150mm plastic Super-Sens
50250-XXX 1000mm or 2000mm plastic Tower-Sens