How to Use the Radalert 100
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
This presentation is intended to give the user a brief overview of how to
operate the Radalert 100. For a complete understanding of this instrument
please refer to the operating manual.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
What the Radalert 100 Does
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The Radalert 100 measures the
rate of the following types of
nuclear radiation
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The Radalert 100 measures the
amount of radiation in
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Alpha
Beta
Gamma
X-radiation
Counts per minute (CPM & CPS)
or
MilliRoentgens per hour (mR/hr)
or MicroSieverts per hour
(µSv/hr).
The Radalert 100 can audibly alert
the user when a pre-determined
level of nuclear radiation occurs.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Turn On Radalert 100
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Turn the Radalert 100 on by
moving the lower switch from Off
to On or Audio.
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On--The Radalert 100 is
measuring radiation but there is
no audio.
Audio--The Radalert 100 is
measuring radiation, and beeping
with each count of radiation that is
detected.
When the Radalert 100 is first
turned on it does a 3 second
system check, displaying all the
indicators and numbers.
After the system check is finished
the Radalert 100 shows the
current radiation level.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Select the Operating Mode
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Move the upper switch to
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Total / Timer
CPM / CPS (counts per minute or
counts per second).
mR/hr or µSv/hr (milliRoentgen
per hour or microSievert per
hour).
In Total / Timer mode the
Radalert 100 starts totaling the
counts it registers, and updates
the numeric display each time it
registers a count.
In the CPM / CPS and mR/hr /
µSv/hr modes the numeric display
is updated every three-seconds.
The CPM / CPS mode is the
easiest to understand.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Switch the Mode
in the Utility Menu
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To switch the mode from
mR/hr to µSv/hr and from
CPM to CPS:
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Turn the Radalert 100 off.
Hold down the + button on the
end panel while turning the
Radalert 100 on. The menu
icon will appear at the lower
right corner.
Scroll through the numbers on
the screen by pushing the +
and - buttons until you get to
2.
Press the SET button on the
end panel. Press + for mR/hr
(CPM) and - for µSv/hr (CPS).
Press the SET button twice.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
What is Background Count?
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The background count is the normal
level of nuclear radiation that is
occurring at a given time and place.
Some sources of background radiation
are:
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The sun
Minerals in the earth
Residual radiation from nuclear testing
and other man made sources
Nuclear radiation is a naturally
occurring phenomenon. When the
Radalert 100 is on it is normally
measuring the background count.
A user should determine the normal
background count to be able to set the
appropriate alarm level in the case of
abnormal levels of nuclear radiation.
January 2012
The mesh screen covers the end window of the Geiger-Mueller sensor.
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Determine the Average
Background Count
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Turn the Radalert 100 on, and put
it in CPM / CPS mode.
Wait one minute until the
hourglass icon on the left side of
the screen disappears. After this
icon disappears the Radalert 100
updates every three-seconds.
Take 30 consecutive minute
readings and record each of the
readings.
Add together each of the readings
and divide this number by 30 (the
length of your timed count).
This number is the average
background count.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
Considerations Involved in Finding
the Best Level to Set the Alert
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The ideal alert setting provides enough sensitivity to detect any
increase in the radiation level above naturally occurring background
levels without false alarms caused by normal random variations in
the background radiation level.
A good setting for one location may cause alerts in another location
since background radiation levels can vary due to
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altitude
geography
radon gas
radioactive materials in buildings
mineral content in soil and rocks
Each user should balance the need for sensitivity against false
alarms occurring from local geography and conditions.
A good alert level can be developed experimentally or through the
formula found on the next slide.
Use this number and adjust it as necessary for local conditions.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
One Way to Determine Where to
Set the Alert
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Use the Radalert 100 in CPM / CPS
mode to measure counts for 30
consecutive minutes.
Record each reading.
Add the readings and divide the sum
by 30.
Find the difference between each
reading and the average.
Square each of these differences
(multiply it by itself).
Total the squares of the differences
and divide the sum by 29.
Find the square root of this sum. This
number is the standard deviation.
Multiply the standard deviation by 4
and add this number to the average
from step 3 above. Set the alert level
to this number.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Set the Alert
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Put the Radalert 100 in CPM /
CPS mode.
Press the Set button on the end
panel. A nuclear radiation icon will
appear on the left side of the
screen.
Use the + or - buttons to set the
alert level to the desired setting.
Press the Set button twice. The
nuclear icon remains on. This icon
means that the alert is set.
Each time you turn the Radalert
100 on you will have to turn on the
alert feature, but the setting will
remain the same.
January 2012
International Medcom, Inc. 707-823-0336
www.medcom.com
How to Change the Battery
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January 2012
Turn the Radalert 100 over.
Remove the battery cover.
Detach the 9 volt alkaline battery from the wire connector and replace.
The battery life for the Radalert 100 is approximately 2,160 hours at normal
background, average 625 hours at 1 mR/hr with beeper off.
International Medcom, Inc. 707-823-0336
www.medcom.com