Light Sensitive GM Tube

[epombier@mednet.med.miami.edu]

     We have a Ludlum Model 44-7 thin end window G-M detector which appears 
     to have become light sensitive.  When the window is exposed to bright 
     light you get a significant response.  If you mask half of the window 
     you find that the response varies as you rotate the mask.  The 
     detector still responds appropriately to radiation and the background 
     is not inordinately high at normal indoor lighting levels.
     
     Any thoughts as to the cause of the phenomenon.
     
     Ed Pombier
     Director 
     University of Miami Radiation Control Center
     (305) 243-6369
     epombier@mednet.med.miami.edu