BERTHOLD TECHNOLOGIES LB 480, User Manual

Page: 411 / 450

SENSseries LB 480 Level measurement
BERTHOLD TECHNOLOGIES GmbH & Co. KG
3 – 411
Volume 3 7 Explanations
3
7
Explanations
7.1
Background
The term "background" refers to the count rate resulting from the
natural environmental radiation. The background level is largely
dependent on the scintillator volume. The background is not
accounted for by the decay compensation as it is regarded as a con-
stant.
An error when recording the background may later lead to drift
effects in the measurement. Influences from neighboring radiation
sources must be avoided.
The background has to be recorded only for SuperSENS, UniSENS
and TowerSENS. The background need not be recorded for the
CrystalSENS.
Below we will present three options for measuring the background.
The best approach for your background measurement is dependent
on the situation on site and on the type of radiation source.
Best solution
With empty ( Fig. 7-1 left) or full ( Fig. 7-1 right) tank and mounted
detector, but without the shielding or without the source installed in
the shielding.
IMPORTANT
The detector must not receive any radiation from the radiation
shielding which has been put on the side and is closed. To this end,
the shielding with the source has to be put in an adequate distance
(approx. 15 m), or behind a thick concrete wall.
Fig. 7-1 Best solution
Detector Detector