Monochromator
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  B2 Slit to shield
     the diffuse scattered
     radiation from the
     inside of the housing

     
     Left: Beam distributor
     box with outlet 
  C  to the monitor counter 
     and beam guide
     to the sample
  
     The window in front
     allows observation of
     the monochromatic
     radiation on a 
     fluorescent screen