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Geiger Counter

Last year (2011) I got interested in radiation - partly due to the Fukashima nuclear melt down. So I bought a simple Geiger counter kit and built it. Sure enough I got average background readings as audible clicks of 6-12 counts/minute which is normal for Maine. So then I geeked out and added a LCD that shows counts/minute (CPM) with is one standard way of quantifying radiation.

Here it is showing 10 counts for the previous minute:

Iím pretty pleased with it. The Geiger-Muller tube is rated to detect alpha, beta and gamma particles. This means that while it can be used for local testing of ionizing radiation, it should also be able to detect astronomical events such as the radiation from solar flares.  So I interfaced it to the web using a spare port on one of my ioBridges so that I could see charts of radiation over a 24 hour and 7 day period.  Here's the schematic of my interface from the Geiger Counter to the ioBridge pro module.  I got some nice, consistent readings for a week or so. Then I saw a news item about a large CME (Coronal Mass Ejection - like a solar flare) that was due to hit earth on July 12/13, 2012. Click here to learn more about that event and the aurora that it triggered. So several days later I remembered to check my 7-day chart, and . . . there it was - a peak in radiation coinciding with the arrival of the radiation as it hit the earth! Cool! Hereís the chart showing the peak:
July 12-18, 2012
Since then I have detected other CMEs - if you see a spike in the 7-day chart below it was probably due to a solar event.  Of course a sustained increase could represent BAD NEWS like a nuclear plant leak!

I have decided to make the data live on my site for the interest of my web viewers.  Below are a 24 hour and 7-day view of the most recent readings.  You can hover over the charts to see specific readings, or click/drag across the chart to zoom in.  The detector has recorded counts in the last minute (click the number to refresh).

Update October 4, 2014.
The original DIY Geiger counter kit became unreliable and started producing very high count rates so I have replaced it with an updated kit made by RH Electronics
RH Electronics Geiger Counter DIY kit
This design has a better high-voltage regulation circuit for the Geiger-Mueller tube that improves performance.  I modified the kit very slightly to make it compatible with the ioBridge.


For more details about Space Weather go to the
Space Weather Prediction Center run by NOAA