From: zapkitty@gmx.co.uk   
      
   On Wed, 19 Jan 2005 12:16:05 -0800, David Summers wrote:   
      
   > My understanding is that for radiation, it doesn't really matter what   
   > the mass is, only the amount of mass figures in.   
      
   Incorrent. You've forgotten secondary radiation.   
      
   The classic example is a high energy particle...if it hits water it   
   might be stooped, or it might pass through... but your steel shielding   
   stops it cold, and in stopping the particle the steel in turn releases   
   a blast of secondary particles into the vehicle that do far more damage   
   to the crew than the the original particle would have done.   
      
   The composition of a radiation shield matters very much indeed.   
      
   --   
   Chuck Stewart   
   "Anime-style catgirls: Threat? Menace? Or just studying algebra?"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)