Re: Why we use Zn and Cu company with Pb in shielding gamma ray?

Lead is a great shield for gamma rays.  However, the interactions in the
lead, which is a high Z material, produce x-rays.  To reduce the exposure
from x-rays a thin metal layer, of a lower Z material, is frequently used.
 Copper or tin are common choices.  These types of shields are refered to
as "graded Z" shields.


For further information try
 http://www.ortec-online.com/detectors/photon/b6.htm
 http://www.canberra.com/literature/944.asp