Re: Interesting shielding question: lead vs. cobalt

Hello...

While I can't answer your question reguarding the shield with a lot of
confidence, I wanted to point out that microwave radiation is a form of
electromagnetic radiation (lower on the EM spectrum than X-Rays and gamma
rays).   I'd also like to point out that lead has different attenuation
(absorption of x-rays) for different energies of x-rays used.  The shield
used for your film is probably not as thick as the lead shielding used to
protect YOU when you get a x-ray (I can only guess that the x-rays used at
the airport and what not are probably way lower energy than normal x-rays,
hence it's seeming inability to block your phone calls).  Hope this helps.
________________

Jennifer L. Rosen

Class of 2005
The Ohio State University
School of Allied Medical Professions
Division of Radiologic Technology

rosen.66 at osu.edu
www.disturbedecho.com

"jshell" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hello,
>
> Something interesting happened to me and I would appreciate if someone
could
> shed some light on this mystery:
>
> I bought a "film shield" bag at a store. These are lead bags designed to
> protect photographic film from airport radiation. When I left the store
the
> theft alarm went off. The security guard pointed out that the sales clerk
> had forgotten to deactivate or remove a "theft strip" which was INSIDE the
> bag. (These are metal strips designed to trigger an alarm when move close
by
> the sensors). I was very surprised by that happening. I thought that lead
> would shield any radiation from the sensor. Then I went home and did a
> simple test: I placed my cell phone inside the bag and tried to place a
> call. To my dismay I could call out without a problem. I am very confused:
> Lead obviously cannot shield microwave radiation (the radiation from the
> phone) and electromagnetic radiation (which is used in theft devices, I
> think). I thought that lead shields all radiation? How come it does not?
How
> would my test results have been had I used a cobalt bag?
>
> Thank you for your input.
>
> Ken Aro
>