Subject: What can be used to reflect gamma rays?

I know that mirrors of various materials can be used to reflect visible 
light, but is there a way to construct a 'mirror' of some description to do 
the same for gamma rays? I know of the penetrating power of high energy 
photons, and I was wondering if there is any means by which you can 
increase the number of the photons reflected by some sort of mirror of 
matter or energy.

Re: What can be used to reflect gamma rays?