Geiger Counters for Detecting Radon

It is not very clear whether Geiger counters can be used for detecting radon. The Radalert 50, Radalert 100, Inspector Alert and Inspector do not measure radon gas specifically, however experiments that use the Radalert in a controlled environment with different radon gas levels showed that the average counts per minute increased and came down with radon concentrations.

The radiation measured integrates emissions from radon and its daughters. The experiment results showed a linear increase of counts per minute with respect to increased radon concentration from 17 CPM at 0 radon concentration to 33 CPM at a concentration of 65 pCi/l. At 4-5 pCi/l, the increase was 1 CPM. Till now, the Inspector has not been tested whether it can detect radon, however it should be effective especially because it has a high sensitivity to alpha and beta radiation. It is not recommended that the Radalert 50, Radalert 100, Inspector, or the Inspector Alert be used as an alternative to EPA-approved carbon canisters or other standard methods of testing for radon.

Use of Radalert 100 or the Inspector Alert for Experimental, Educational, or Screening Purposes

The following guidelines may be helpful if one wants to use the Inspector Alert or the adalert 100 for experimental, educational, or screening purposes in regards to radon, which are:

  • Radon may most probably enter in homes or other buildings through cracks or openings in the floor around pipes or conduit, unsealed wall-floor joints, and underground hollow block walls. Dirt floors in basements are the most vulnerable. Unventilated basements or closets normally have levels of radon than well-ventilated areas.
  • Before radon screening, it is important that baseline measurements are established; for example, determine the background level in a location outdoors 3 ft above the ground and in a location in a place in the house not likely to have radon accumulation. It is best to accumulate the baseline counts for 12 h as described below.
  • For radon screening, the instrument is placed on the floor near any suspected entrance point.
  • For accurate results, air exchanges between indoors and outdoors must be kept at a minimum for 12 hours before and during the test.
  • The display is set to Total and the counts are accumulated for 12 h in each location.
  • Divide the total count for the period by the exact number of minutes to get the average CPM.
  • In case the 12-hour average CPM in the home is more than 1 CPM higher than outdoors, further testing for radon can be done using carbon canisters or other EPA-approved methods.
  • Another way of radon screening is by checking dust or air particulates.
  • Several radon daughters, which account for much of the radiation produced by radon, are negatively charged and attach themselves to the dust.
  • Clearing accumulated dust by wiping a television or computer monitor screen with a piece of tissue paper (the CRTs are positively charged and this specifically attracts the negatively-charged particles) or by attaching filter paper or medical gauze to a vacuum cleaner nozzle and running it for half an hour.
  • Dust can also be determined on an air-conditioning, heating system, or air-purifying filter.
  • A high measurement from concentrated air particulates is an indication of the presence of radon.
  • Since the radon daughters are concentrated, high readings are not unusual if any radon gas is present.

This information has been sourced, reviewed and adapted from materials provided by International Medcom.

For more information on this source, please visit International Medcom.


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