Sper Scientific 840026 Radiation Detection Meter - Manual (Page 3)

3
BATTERY REPLACEMENT
The unit is powered by a 9-volt battery. With the on button
activated, the LED should be brightly lit. When the LED is
no longer bright or when the LED dims in the presence of a
radiation source, replace battery. To replace the battery:
1. Slide the plastic door off the unit located in the back.
2. Carefully replace the battery. DO NOT reach into the
unit through the battery compartment while unit is on.
G-M tube activation voltage is over 200 VDC.
3. Replace plastic door.
4. For extended operation and infrequent battery replace-
ment, use an alkaline battery.
OPERATION
The radiation monitor only operates while the push button
on the face of the unit is depressed. This feature makes the
operation very simple and conserves battery power. The
unit is designed to be held in the right hand, with the thumb
over the pushbutton (see Figures 1 and 2). The LED just
above the pushbutton indicates that the unit is on and will
give an indication of battery condition.
When the unit is turned on, a faint buzz may be audible in a
quiet room. This is normal and is caused by the transformer
that powers the G-M tube.
In most parts of the world, background radiation will cause
the speaker to click at random intervals, about one click
every few seconds. In areas where large deposits of natu-
ral radioactive minerals are found, or in an area that has
been contaminated with radioactive materials, the speaker
will click more frequently. This is called the "background
level." It should be taken into account when making meas-
urements on specific objects.
Since the incidence of clicks from radioactive sources is
random, several clicks can be heard in rapid succession,
while on other occasions several seconds may elapse be-
tween clicks. This is normal. Averaged over a period of
time, the click rate should remain relatively constant. A rea-