|T O P I C R E V I E W
|Posted - 02/24/2022 : 00:02:36
Hi there. A basic question? I know the human body is lightly radioactive. So is it possible that the cpm is a little bit higher if you hold the device in your hands instead of laying it on a table (per example). I donít know if this is a stupid question. But whatís your experiences?
Thanks in advance.
|3 L A T E S T R E P L I E S (Newest First)
|Posted - 03/03/2022 : 06:13:51
Hi. Thanks for your explanations and replies. Greetings, Dirk
|Posted - 02/26/2022 : 01:23:30
In principle the idea is correct that the human body should put a few extra counts into a Geiger counter. However ...
The main source for the extra counts of radiation is Potassium (chemical sign: K), due to its content of the radioactive isotope K-40. Bananas actually contain roughly 50% more K-40 than the human body (3.6 vs. 2.5 g/kg). This resulted in the (in)famous definition of the "Banana equivalent dose". https://en.wikipedia.org/wiki/Banana_equivalent_dose
I attempted to verify the activity of bananas using a GMC-300E+ counter, and I succeeded. The results are summarized in my "Going Banana" article, found in my Articles folder on SourceForge https://sourceforge.net/projects/geigerlog/files/Articles/
It takes some long measurement hours, and some digging into statistics to understand "Standard Deviation" and "Standard Error" before one is able to confirm success!
As the human body has lower K-40 content than a banana, longer times will be needed. Given that the statistic improves only with the square root of the counts, my guess is that at least (!) a week-long experiment, with constant recording, and changing every 20 hours from background to hand-holding will give enough data for a firm conclusion.
If you are not prepared for those long counter-sitting periods, maybe you can put the bar a bit lower: cocoa powder, as you can buy it from the supermarket, has even 4 times higher potassium than bananas (15.2 g/kg). My counter gave this result for switching between background and intimate contact between counter and cocoa powder:
But note the time scale: be patient when the count rate is low! And always verify proper Poisson statistics for your work to be valid, see article.
|Posted - 02/25/2022 : 10:10:08
Hi Dirk, probably not. The geiger counter might not be sensitive enough to see the difference.