The HERMES dual radiator RICH—Performance and impact

The HERMES RICH is a novel dual radiator detector which provides clean particle identification of pions, kaons, and protons over the traditionally difficult momentum region of 2– 15 GeV / c . Extensive operating experience acquired since installation at HERA confirms stable operation at design levels. Particle identification with this instrument has proven to be essential for almost all recent HERMES physics studies. Typical physics results obtained are discussed together with options for improving the RICH performance.