XPost: sci.physics   
   From: hwabnig@.-   
      
   On Mon, 2 May 2011 17:25:33 +0100, "Androcles"   
    wrote:   
      
   >   
   >"Helmut Wabnig"  wrote in message   
   >news:grktr6tls73h025ahso469e69mg14jvtd9@4ax.com...   
   >| Doing some repair work on scintillator probes for gamma and beta   
   >| radiation I have to replace the  metalized Mylar cover.   
   >| Trying with 11 µm kitchen aluminium failed firsthand.   
   >|   
   >| The Mylar foil is only 4 µm total but worked fine before in subdued   
   >| daylight. I do not know what metal is used on the Mylar.   
   >|   
   >| Why the kitchen aluminium fails is unclear to me,   
   >| Possibly it has small invisible pores which let pass some light.   
   >|   
   >| The question is, how thick must an aluminum layer be   
   >| to block light 100%. Cannot find reasonable data.   
   >| Google becoming more and more useless,   
   >| returning about 100000 school projects with no information.   
   >|   
   >| w.   
   >|   
   >A DVD stops direct sunlight, but my laser pointer shines   
   >right through it.   
   >   
   During a solar eclipse CDs and/or DVDs are quite useful   
   for watching the event as it goes on.   
      
   w,   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)