Figure 7.2: LB 1343, scintillation probe with 345 cm²
The scintillator is applied on a transparent carrier. The foil is
stretched over a frame and protected by a metal grid. The de-
tector is fixed to the underside of the cover with four screws.
The frame with foil can easily be exchanged. The radiation en-
trance window can be protected by a metal protection plate.
The reflector and the photomultiplier are located in the case, di-
rectly behind the scintillator. The enclosure also accommodates
the electronics with evaluation and correlation circuit. The asso-
ciated high-voltage is already set at the factory. A service
adapter is required to check and change the high voltage; this
work must be carried out by experienced service personnel.
7.2.1 Cleaning the Detector Window of
Contamination Probes with Scintillator
The window foil of the detector is sensitive to mechanical dam-
age. It is therefore protected by a protective grid. However, eve-
rything should be done to avoid destruction of the window foil
(sharp objects, measurement on stubble fields, rose bushes
and cat's paws!).
For easy cleaning of a dirty window foil, you can take off the
outer protective grid after cautiously loosening the Phillips
screws.
Carefully clean the detector window foil with a soft brush (dust)
or with alcohol or detergent solution. Then dry it using a hair-
dryer that must not be too hot. When you re-insert the protec-
tive grid, please be careful not to damage the foil with the
screws or the screwdriver!
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