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[aprssig] An accurate do-it-yourself radiation meter

aprssig at k7ftp.net aprssig at k7ftp.net
Fri Feb 10 23:53:01 UTC 2012

Solely on the topic of radiation meters....

I was in High School in Oregon during the Chernobyl incident.  I still
remember many "experts" saying that it would not be detectable in North

It turned out that Portland General Electric (because of the Trojan Nuclear
Power Plant) had a unit that they offered to schools on radiation, and it
included a set of detectors.  We were participating in it from immediately
before Chernobyl and had the detectors at the time.  

My job as a lab assistant was to go in at the same time every morning, and
track the ambient background radiation.  That way, we could subtract the
normal ambient average from the counts we got on sample materials, and get a
more accurate count.  

When the cloud from Chernobyl passed over western Oregon, the background
count increased by a measurable amount.  It was certainly not dangerous, but
we could clearly tell that when the cloud passed over, the ambient
background count increased.  It turned out that the local paper was very

I remember the school getting calls from all sorts of people - NRC, EPA, a
bunch of agencies.  They wanted to clarify that it was not dangerous.
Apparently they didn't like a bunch of high school kids proving that it was

He moral of the story is that if you can keep track of your daily ambient
counts, you can tell if anything has changed.  Having the gear to do so
would be very handy.  Then you could use APRS to post notices if something
changes in your local area - perhaps useful in an emergency.  How's that for
tying in into the relevant topic.  


-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Bob Bruninga
Sent: Friday, February 10, 2012 4:30 PM
To: 'Phil'; 'Tacos AMRAD'
Cc: aprssig at tapr.org
Subject: Re: [aprssig] An accurate do-it-yourself radiation meter

What I don't get is the 2 orders of magnitude difference in capture area.
Sure, ANY PN device can in someway be a radiation detector, but the Geiger
tube has a hundred times more capture volume than most any PN device.

So as far as giving an idea of background radiation, I cannot see these
point source detectors as much more than a curiosity.  Or I am missing
something.  I think the best detector is a LCD display with background
plazma lighting.  Bias the lighting electrodes just below threshold and then
any event anywhere in the 1/2 square foot area should be detectible?

Subject: Re: An accurate do-it-yourself radiation meter


Or am I missing something.


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