aero ektar storage

[jimmygcreative]

Happy Hoidays,

I own a 2.5 178mm aero and was wondering what distance should I store the item when not shooting?

thanks

[Walter Calahan]

Distance from the subject or your privates? Grin.

I simply put them in a closet.

We probably get more radiation from background noise from the environment, especially if you live out west with lots of young rocks.

Just don't hold it for too long between your legs.

[Daniel_Buck]

I keep mine in a far corner of the apartment that I don't usually sit in. I've been kind of wondering the same thing as well, how others store theirs. Would storing it in some sort of metal box be better? (even though it's only mildly radioactive?)

[John Kasaian]

I lined a 6"x6"x6" card board box with scraps of wonderboard, a cement inpregnated fiberglass used as a backer for tile. When I took my aero-ektar to the nuiclear medicine lab at the local hospital for testing they also tested the lens in this box and the tech gave it a "thumbs up"
FWIW the radiation given off by my Aero Ektar blended into background radiation within 9 or 10 inchesof the lens IIRC.
Keep it away from children, they told me.
You might inquire and see if the nuke lab at your local hospital will test it for you---it makes for an interesting 20 or so minutes (its worth it to see the expression on the secretary's face when you walk in to the hospital and tell 'em you have something that's radio active that you brought in for testing!)

[John Kasaian]

Oh yeah, before I got the thing tested I kept it in the garage.

[Daniel_Buck]

FWIW the radiation given off by my Aero Ektar blended into background radiation within 9 or 10 inchesof the lens IIRC.

was this the bare lens? or the lens inside your box?

[John Kasaian]

The lens by it's self. Inside the box we could only pick up back ground radiation. FWIW, I also seperated the elements and more radiation was emitted by the rear element than the front.
If you do a search you'll find my original post on the subject which I wrote immediately after the testing. I'm working from memory right now and at 1:30AM my memory ain't workin' so good!
As I said, it was a very interesting 20 or so minutes.

[Asher Kelman]

I thought it might be helpful to get some data here

NUREG-1717 estimated that the dose to the operator of a television camera using thoriated lenses could be as much as 60 mrem per year. This assumed that three of the camera’s lenses contained 30% by weight thorium and that the camera man was positioned behind the camera for 1000 hours per year. Nevertheless, there is no evidence to suggest that thoriated lenses are commonly used in television cameras.

Measurements have indicated that the exposure rate at a depth of 10 cm in the body of an individual carrying a camera containing 0.36 uCi of thorium would be approximately 0.01 mrem/hr. Based on this value, NUREG-1717 calculated that a serious photographer might receive an annual exposure of 2 mrem. This assumed that the photographer carried the camera 30 days per year and for 6 hours per day. They also estimated an exposure of 0.7 mrem per year for an average photographer. If the camera lens contained the maximum permitted concentration of thorium (30%), NUREG-1717 estimated that the aforementioned annual doses could triple.

The alpha radiations will be mostly stopped with a piece of cardboard or better a thin sheet of led in over over the ground glass protector. I imagine that the lead line bags might totally block the low energy alpha particles but I haven't checked the actual energies. However the gamma radiations can be best avoided by placing the camera even 3 feet instead of an average of 1 ft and the dose will drop by the inverse square law and would be in that case 1/9 of the estimated dose.

Eyepieces with thorium should be avoided. The does to the eye would seem to be too dangerous and the cornea is sensitive to damage!

Also remember that some of the Pentax Takamurs had the Thorium Oxide to increase Refractive index but maintain low dispersion. Yes, that includes my 50 mm 1.4 Super Multicoated Takamur and I will measure it for any radiatation! Damn!!

Asher

[Dan Fromm]

http://home.earthlink.net/~michaelbr...aeroektar.html

You characters worry entirely too much.

[Daniel_Buck]

better safe, than sorry :-)