what does sielding mean??
>sielding = shielding
just a typo, then.
WW,
Fe = iron, probably*, and
PMT = photomultiplier tube
* When I worked in an atomic physics lab they used a special type of metal to keep magnetic fields out of the experimental area. Very expensive. It was called mu-metal (as in the Greek letter mu which is used to represent the magnetic permeability). Maybe the Fe-shielding is similar.
Maybe the Fe-shielding is similar
Soft iron will shield, to some extent, against magnetic fields. Probably not as welly as mu-metal, but if the application isn't as senstive, probably well enough.
It has to do with the magnetic properties of the metal. Lead isn't magnetic. So it can't be used to shield from magnetic fields. Iron is magnetic. Mu-metal is probably some fancy alloy. Super-duper expensive.
You're probably thinking of radiation shilding. A whole different ballgame. In that case they do use lead. And depleted uranium. Edit: and concrete, and heavy concrete. And other stuff.
heavy concrete
Is that concrete they made using heavy water?
I don't remember what's in it and since it was my last degree that was in medical physics, my radiation protection course notes are at home. I don't know what makes it heavy. For that matter, it might be called dense concrete. Anyway, it's expensive but you need less of it for a given amount of shielding.
http://web.ead.anl.gov/uranium/uses/snfwaste/index.cfmNow all we need to know is what's DUO2? Depleted uranium dioxide?