Interesting fact about your FED-5 and it's Industar-61L/D

[moos blues]

Hey all...

I think this may be a known fact but never the less interesting.

the reason for this is discussed the the article linked bellow, but mainly it's because of the Industar-61L/D. The Industar contains potentially radioactive lanthane glass in one of it's elements.

Quite interesting if you ask me...

...I placed the Geiger tube against the Industar-61L/D's glass surface and started the clock. The value I got was about twenty-five to twenty-eight ionisations per ten seconds. After subtracting the background radiation, that means the Industar-61L/D's radiation alone is responsible for around six to eight ionisations per ten seconds.

this was an extract from Fed 5 radioactive?

 

[Keltzar]

yup.
not only the industar, but many other lenses are radioactive too... although in many cases its thorite glass.
e.g. m42 ver. pentax Super-Takumar 35/2, ST and SMC-T 50/1.4, kodak ektar lenses...
they also have much higher levels than the I61.

Also, if I am not wrong... the geiger cannot tell what type of radiation. Alpha and beta particles ... one of them just bounces off your skin ... and the other is only dangerous in big quantities and through an open wound ...

only gamma rays are immediately dangerous.

so that said, there is nothing to worry about.

interestingly... has anyone tried a geiger on the sigma APO lenses ? I hear they use lanthanide in the APO element.

On a related topic... radioactive substances are all around us. Up to 1950 or so... radium was used to give the hands of clocks and watches the lume in the dark. Later they used tritium which is also radioactive but quite safe. M16 gunsights use tritium. Smoke detectors use Americinium.

There is a book I read called the "Radioactive boy scout". Good read. It's about how a 16-yr old American boy illegally built a a breeder nuclear reactor in his backyard by buying old clocks,watches, smoke detectors etc. and building up a small pile of radioactive material and actually succeded in getting a fission reaction going. The US Govt. had to shut him down, decontaminate his home, and counsel him.
And its a true story.

 

[alternatve]

Yep, read about it before. Thing is, you get more radiation from standing out in the sun, or usign a laptop on your lap! ?!

 

[moos blues]

It's about how a 16-yr old American boy illegally built a a breeder nuclear reactor in his backyard by buying old clocks,watches, smoke detectors etc. and building up a small pile of radioactive material and actually succeded in getting a fission reaction going...
And its a true story.

now thats something... woah. :bsmilie:

yea loads of stuff was radioactive last time... esp russian stuff, was watching a docu about how they thought radiation was good for a wide wide range of applications... haha