EPD/HB/40521/
000
ELECTRONIC PERSONAL DOSEMETER HANDBOOK
TECHNICAL DESCRIPTION
ISSUE 5
Page 42
Thermo
4.2 Electrical Description
4.2.1 Electrical Characteristics
Power Supply: One AA Lithium Thionyl Chloride (LTC) battery 3.6 V),
giving typically 5 months continuous operation at an
average dose rate <5
µ
Sv/h with the alarm sounding <5
hours total during battery life.
or:
One standard AA Alkaline battery (1.5 V), giving typically
55 days continuous operation at an average dose <5
µ
Sv/h
with the alarm sounding <2 hours total during battery life.
Confidence Test: Activated on start-up and by the button when the
CONFIDENCE TEST mode is called-up (see Section
3.5.7).
Detector Test: Performed during the start-up sequence and as a
background test, and under demand via the IR interface .
Normal dose processing is inhibited during detector test for
a period of 1 to 2 ms.
Battery Test: Configurable time interval between 1 to 60 minutes.
(15 minutes recommended).
Alarm sounder : 98 dB(A) to 101 dB(A) at 20 cm (4kHz loud mode)
80 dB(A) to 90 dB(A) at 20cm (4kHz quiet mode).
4.2.2 Battery Management
The EPD circuitry is designed to operate at 3.6V DC. The EPD can be powered
by either a 3.6V Lithium Thionyl Chloride (LTC) (Sulphurous Oxychloride, SOCL
2
)
battery or a standard 1.5V AA Alkaline type battery.
The EPD software runs an internal battery condition test at regular intervals
(between 1 and 60 minutes). This time interval is factory preset to 15 minutes and
should not be adjusted except following consultation with Thermo Electron.
EPDs prior to software version 11:
If a 1.5V Alkaline battery is installed the EPD automatically switches-in a step-up
converter to maintain the 3.6V operating voltage. The step-up converter is also
switched in as the LTC battery runs down. However, the EPD will not start up if it
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