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FAQ: Test sources

Posted: Tue May 22, 2012 6:40 pm
by mightyohm
Test sources:

My kit will not respond to bananas, at least not in an obvious way. I believe that a more sensitive pancake-style detector is required - bananas just aren't that radioactive. It may be possible to see a small signature using a large number of bananas (I hear some types are more radioactive than others) and a long sample time (extended data logging). It will not be an easy measurement.

Camping mantles made in the last several years are NOT radioactive. If you purchase a mantle from a sporting goods store, Target, etc it will NOT be radioactive, I have checked!

Also, my geiger kit will not detect much radioactivity from a smoke detector, so that is also not a good test source (and disassembly of a smoke detector is dangerous). The results will be disappointing, anyway.

Good test sources include:
- some granite countertops
- vaseline (depression) glass, available on eBay as uranium marbles
- orange/red Fiestware produced before the 1960s (eBay)
- old watches with Radium dials (probably pre-1960s, ordinary glow in the dark watches won't work)
- uranium or other radioactive ore samples (eBay, United Nuclear)
- thoriated welding rods (welding supply store, eBay)
- old camping mantles containing Thorium (eBay)
- some camera lenses with thoriated optics, but these are rare (maybe available from antique camera dealers or eBay)
More info here: ... t-sources/

Re: FAQ: Test sources

Posted: Wed Jun 27, 2012 5:16 pm
by wkhilarides
I'm a good source! I had a Prostate Brachytherapy implant two weeks ago. They implanted 97 Ceramic Cesium 131 seeds in my prostate. I need to stay away from children, and can't sleep n the same bed with my wife. I am currently emitting 120,000 CPM, but the radiation falls exponentially with distance from my prostate radiation (CPM) = 10890*e^(-0.281*Distance(in)). I'm not sure of the calibration, since I have such a strong impact on the readings. We have red FiestaWare plate that reads about 12,000 CPM. 131Cs has a half life of 9.7 days. and an average Photon energy of 29 keV. I will see if the the radiation is reduced by half nine days from now.

Does the device send one data point per second? It looks like uSv/hr = 0.0059* CPS.

This is great! Thanks

Kurt H.

Re: FAQ: Test sources

Posted: Wed Jun 27, 2012 10:56 pm
by mightyohm

Wow, 120,000 CPM! :o

Yes, the serial port sends one update every second.

Re: FAQ: Test sources

Posted: Sun Aug 18, 2013 5:24 pm
by thegrendel
Another good radioactive source:
Certain of the "Quantum Scalar Energy Pendants" available
on eBay and from various other sources. I got a "FusionExcel"
model, complete with Authenticity Card for $6.99 (shipping included)
on eBay a few months back. Close up to an SBM-20 tube it reads
400 cpm (normal background here is 20).

Google "quantum scalar pendant radioactive" or see:
for example.

And by the way, my QSE Pendant was one of the first things
I used as a check source with the MightyOhm geiger kit I just
finished building. Beep-beep-beep, flash-flash-flash.

Re: FAQ: Test sources

Posted: Tue Aug 20, 2013 10:54 pm
by mightyohm
I haven't seen this pendant before. 400 cpm is not bad.
Let me know if you find any truth to the "healing properties". :lol:

Re: FAQ: Test sources

Posted: Mon Mar 03, 2014 3:41 pm
by killswitch

Another test source i found that works is fertilizer. Ive got a bag of NPK powder mix and the K in it gives off about 80CPM's.

A pure bag of K before mixing will probably give off more.

Re: FAQ: Test sources

Posted: Sat Mar 15, 2014 10:18 am
by mightyohm
I'm guessing this is due to naturally occurring K40, the same reason that salt substitute (and people) are slightly radioactive.

Re: FAQ: Test sources

Posted: Thu Nov 24, 2016 1:00 pm
by dmainmon
wkhilarides wrote: It looks like uSv/hr = 0.0059* CPS.
Is this the equation used for uSv/hr ?

Re: FAQ: Test sources

Posted: Fri Nov 25, 2016 6:56 pm
by mightyohm
The scale factor used in the code is 0.0057.