ECOTEST PRD GUARDER DKG-24 Operating Manual page 15

The device is powered by two batteries (AA size). It is
possible to operate it from lithium batteries – FR6 with a total
nominal voltage of 3.0 V, from alkaline batteries with a total
nominal voltage of 3.0 V and nickel-metal hydride batteries with
a total nominal voltage of 2.4 V. The device can also be powered
from a USB port with a nominal voltage of 5.0 V.
The device is sealed with paste in the recess of the bottom
cover.
1.4.2 Operation of the device
The device consists of the following main parts: high
sensitivity scintillation detecting unit of gamma radiation
(GSDUh), low sensitivity scintillation detecting unit of gamma
radiation (GSDUl), supply voltage formers (SVF), bias voltage
formers (BVF), GPS/GNSS receiver (NAV), BLE radio module,
display and processing module (DPM), graphical monochrome
display (GMD), batteries (B), thermal detector (TD).
GSDUh and GSDUl consist of a scintillation detector with
a silicon photomultiplier and an amplifier.
The principle of operation of the detecting units is based on
the transformation of scintillations caused by photon ionizing
radiation in the scintillator into voltage pulses in a
semiconductor photomultiplier. These pulses are fed to the input
of the amplifier where they become amplified and come to the
output as pulses of positive polarity. The number of these pulses
is proportional to photon ionizing radiation DER, and the
amplitude is proportional to the energy.
To ensure high temperature stability of the detectors with
silicon photomultiplier, the DPM carries out constant
temperature compensation by measuring the exact values of
temperature at the detectors, and precisely adjusts their bias
voltage.
DPM processes the pulse flows coming from the outputs of
GSDUh and GSDUl, and calculates the value of photon ionizing
radiation DER, which corresponds to these flows considering
the multichannel amplitude analysis, and the pulse count rate
from GSDUh and GSDUl. Depending on the operating mode of
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