| 
  
   
    |  |  |  
    |  | R5900 MA PMTs have proven to be an extremly
    reliable and easy to use detector for Cherenkov photons. |  
    |  | Several new methods were developed for the
    design of the detector surface, analysis of data and alignment of the
    optical system. |  
    |  | The HERA-B RICH counter showed an excellent
    performance in very adverse conditions. |  |