~sober/manuals/degauss_check.txt
					27 July 1997


   VERIFYING THAT THE MAGNET HAS BEEN DEGAUSSED
 
   If you are not sure whether the magnet has been degaussed after the
   last photon beam run, take a hand-held gaussmeter to the upstream end
   of the magnet, near the radiator box.  The stainless steel top arc of 
   the vacuum chamber is accessible inside the magnet yoke.  If the magnet
   has not been degaussed, the magnetic field at the surface of the top
   arc can be as large as 20-30 gauss.  If the magnet has been degaussed,
   the field at the surface of the top arc should be less than 3 gauss.

   If the magnet has not been degaussed, it can be degaussed under local
   control by following the steps given in the file tag_pwr_sup_local.txt
   (Tagger Magnet Power Supply - Local Operation) in this directory.