how to use the radalert 50

March 2005March 2005 International Medcom 707-823-0336International Medcom 707-823-0336www.medcom.comwww.medcom.com

How to Use the Radalert 50How to Use the Radalert 50


This presentation is intended to give the user a brief overview of how to operate the Radalert 50. For a complete understanding of this instrument please refer to the operating manual.


What the Radalert 50 DoesWhat the Radalert 50 Does The Radalert 50 measures the The Radalert 50 measures the

rate of the following types of rate of the following types of nuclear radiationnuclear radiation AlphaAlpha BetaBeta GammaGamma X-radiationX-radiation

The Radalert 50 measures the The Radalert 50 measures the amount of radiation in amount of radiation in Counts per minute (CPM) orCounts per minute (CPM) or MilliRoentgens per hour MilliRoentgens per hour

(mR/hr).(mR/hr). The Radalert 50 can audibly The Radalert 50 can audibly

alert the user when a pre-alert the user when a pre-determined level of nuclear determined level of nuclear radiation occurs.radiation occurs.


How to Turn On Radalert 50How to Turn On Radalert 50 Turn the Radalert 50 on by Turn the Radalert 50 on by

moving the lower switch from moving the lower switch from Off to to On or or Audio.. On--The Radalert 50 is --The Radalert 50 is

measuring radiation but there measuring radiation but there is no audio.is no audio.

Audio--The Radalert 50 is --The Radalert 50 is measuring radiation, and measuring radiation, and beeping with each count of beeping with each count of radiation that is detected.radiation that is detected.

When the Radalert 50 is first When the Radalert 50 is first turned on it does a 3 second turned on it does a 3 second system check, displaying all system check, displaying all the indicators and numbers.the indicators and numbers.

After the system check is After the system check is finished the Radalert 50 shows finished the Radalert 50 shows the current radiation level.the current radiation level.


How to Select the Operating ModeHow to Select the Operating Mode

Move the upper switch toMove the upper switch to Total CPM (counts per minute) (counts per minute) mR/hr (milliRoentgen per hour) (milliRoentgen per hour)

In In Total mode the Radalert 50 mode the Radalert 50 starts totaling the counts it starts totaling the counts it registers, and updates the numeric registers, and updates the numeric display each time it registers a display each time it registers a count.count.

In the In the CPM and and mR/hr modes the modes the numeric display is updated every numeric display is updated every minute.minute.

The The CPM mode is the easiest to mode is the easiest to understand for the layperson.understand for the layperson.


What is Background Count?What is Background Count?

The background count is the normal The background count is the normal level of nuclear radiation that is level of nuclear radiation that is occurring at a given time and place. occurring at a given time and place.

Some sources of background radiation Some sources of background radiation are:are:

The sunThe sun Minerals in the earthMinerals in the earth Residual radiation from nuclear testing Residual radiation from nuclear testing

and other man made sourcesand other man made sources Nuclear radiation is a naturally Nuclear radiation is a naturally

occurring phenomenon. When the occurring phenomenon. When the Radalert 50 is on it is normally Radalert 50 is on it is normally measuring the background count.measuring the background count.

A user should determine the normal A user should determine the normal background count to be able to set the background count to be able to set the appropriate alarm level in the case of appropriate alarm level in the case of abnormal levels of nuclear radiation.abnormal levels of nuclear radiation.

The mesh screen covers the end window of the Geiger-Mueller sensor.


How to Determine the Average How to Determine the Average Background CountBackground Count

Turn the Radalert 50 on, and put it Turn the Radalert 50 on, and put it in in CPM mode. mode.

Wait one minute until the Wait one minute until the hourglass icon on the left side of hourglass icon on the left side of the screen disappears. After this the screen disappears. After this icon disappears the Radalert 50 icon disappears the Radalert 50 updates once per minute.updates once per minute.

Take 30 consecutive minute Take 30 consecutive minute readings and record each of the readings and record each of the readings.readings.

Add together each of the readings Add together each of the readings and divide this number by 30.and divide this number by 30.

This number is the average This number is the average background count.background count.


Considerations Involved in Finding Considerations Involved in Finding the Best Level to Set the Alertthe Best Level to Set the Alert

The ideal alert setting provides enough sensitivity to detect any The ideal alert setting provides enough sensitivity to detect any increase in the radiation level above naturally occurring background increase in the radiation level above naturally occurring background levels without false alarms caused by normal random variations in levels without false alarms caused by normal random variations in the background radiation level. the background radiation level.

A good setting for one location may cause alerts in another location A good setting for one location may cause alerts in another location since background radiation levels can vary due to since background radiation levels can vary due to altitude altitude geography geography radon gas radon gas radioactive materials in buildingsradioactive materials in buildings mineral content in soil and rocksmineral content in soil and rocks

Each user should balance the need for sensitivity against false Each user should balance the need for sensitivity against false alarms occurring from local geography and conditions. alarms occurring from local geography and conditions.

A good alert level can be developed experimentally or through the A good alert level can be developed experimentally or through the formula found on the next slide. formula found on the next slide.

Use this number and adjust it as necessary for local conditions.Use this number and adjust it as necessary for local conditions.


One Way to Determine Where to One Way to Determine Where to Set the AlertSet the Alert

Use the Radalert 50 in Use the Radalert 50 in CPM mode to mode to measure counts for 30 consecutive measure counts for 30 consecutive minutes.minutes.

Record each reading.Record each reading. Add the readings and divide the sum Add the readings and divide the sum

by 30.by 30. Find the difference between each Find the difference between each

reading and the average.reading and the average. Square each of these differences Square each of these differences

(multiply it by itself).(multiply it by itself). Total the squares of the differences Total the squares of the differences

and divide the sum by 29.and divide the sum by 29. Find the square root of this sum. This Find the square root of this sum. This

number is the standard deviation.number is the standard deviation. Multiply the standard deviation by 4 Multiply the standard deviation by 4

and add this number to the average and add this number to the average from step 3 above. Set the alert level from step 3 above. Set the alert level to this number.to this number.


How to Set the AlertHow to Set the Alert

Put the Radalert 50 in Put the Radalert 50 in CPM mode. mode. Press the Press the Set button on the end button on the end

panel.panel. Use the Use the + or or - buttons to set the buttons to set the

alert level to the desired setting.alert level to the desired setting. Press the Press the Set button again. There button again. There

will be a short beep, and a nuclear will be a short beep, and a nuclear radiation icon will appear on the radiation icon will appear on the left side of the screen. This icon left side of the screen. This icon means that the alert is set.means that the alert is set.

Each time you turn the Radalert Each time you turn the Radalert 50 on you will have to turn on the 50 on you will have to turn on the alert, but the setting will remain alert, but the setting will remain the same.the same.


How to Change the BatteryHow to Change the Battery

Turn the Radalert 50 over.Turn the Radalert 50 over. Remove the battery cover.Remove the battery cover. Detach the 9 volt battery from the wire connector and replace.Detach the 9 volt battery from the wire connector and replace. The battery life for the Radalert 50 is approximately 2,000 hours.The battery life for the Radalert 50 is approximately 2,000 hours.

how to use the radalert 50

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