Radioactive sources

This is my actual collection of radioactive sources.

Thorium Kodak lens

Kodak had made some 35mm analog film models of cameras (1950-1970) like Retina IIIc, with thoriated lens. This example is a Retina-Xenon made with thoriated glass. It could be 30% by weight of thorium oxide

This is the gamma emission spectrum of the lens. Mine STS-6 geiger counter one centimeter in front of the lens count aprox. 180 CPM It emit mainly gamma’s and betas… but nothing dangerous for the photographer.

Thoriated welding rods (red for TIG)

Thoriated welding rods for TIG application is a very common and secure radioactive source. You could find the rods at local hardware store. Usualy they are 98% tungsten + 2% thorium by weight. Emission of gamma rays are low, barely over natural background. on the STS-6 geiger counter three rods add 20-30 CPM on the natural background. It mainly emit beta plus some little gamma.

Pechblende uranium ore from Novazza mine

This sample of pechblende is from the biggest mine of uranium in Italy. And in Italy mines are 2… maybe 3 🙂 lol! It come’s from Novazza. The STS-6 counts… 14-16000CPM!!! And SV500 with beta+gamma window opened is in the range of 10-12mRad/h. I store it into a lead enclosure with 5mm thik walls. It’s main emission is… everythink! There is a lot of alpha, A LOT of beta and some cool gamma.

Americium from ionization chamber

You can buy (1.5-2€) from china this little device: an ionization chamber!

It contain some uCurie of americium radioisotope wich emit alpha and some gamma ray. My SV500 placed with beta+gamma window opened fell it like a 1mRad/h source. The main emission of the americium sample is alpha rays but it emit some 59keV gamma rays too.

Please note that if handled correctly, objects manufacted with radioactive isotopes into methal alloy or paint are not dangerous, anyway there are some exception. Eating or breathing radioactive isotopes is dangerous. Don’t pulverize or eat radioactive ores or objects containing radioactive isotopes. Natural radioactive ores could be dangerous if their size are big (emission intensity grow with quantity of emitting material) and if their composition activity is high. Please consider testing natural ores with a calibrated geiger counter in order to ceck it’s activity (must be less than few milliRad/h). Store highly active material into lead shielded enclosures in a secure place.


Author: l.i.papadopol