FAQ: Test sources

[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: http://mightyohm.com/blog/2012/02/feed- ... t-sources/

[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.

[mightyohm]

Kurt,

Wow, 120,000 CPM!

Yes, the serial port sends one update every second.