[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Unidentified device



See NCRP Report No. 95, "Radiation Exposure of the U.S. Population From

Consumer Products and Miscellaneous Sources," page 47.  This summarizes recent

reports on elevated Th-232 and daughters in the camera lenses.  Dose rates of

up to 9.3 mR/hr were found on contact with the lens surface.  The NCRP

concludes that, "If these samples are representative of Th-232 concentrations

in popular 35 mm camera lenses, this source might constitute a significant

exposure of the population...."



On a more practical level, at Fermi 2, we require anyone bringing a camera into

the restricted area to have it surveyed before entering.  Otherwise, it may not

be possible to free release it.  As the Eagles sing in, "Hotel California,"

"You can check out any time you like, but you can never leave..."



The opinions expressed are strictly mine.

It's not about dose, it's about trust.

Curies forever.



Bill Lipton

liptonw@dteenergy.com



"Flood, John" wrote:



> >I have heard of old camera lenses being marginally

> >radioactive (Th-232+decay products).

>

> True.  At one time, thorium oxide was widely used in manufacturing glass to

> change the index of refraction for microscope and camera lenses.  However,

> it hasn't been used for this in decades.

>

> Bob Flood

> Nevada Test Site

>

> ************************************************************************

> You are currently subscribed to the Radsafe mailing list. To unsubscribe,

> send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

> radsafe" (no quote marks) in the body of the e-mail, with no subject line.

> You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/





************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/