a Rich Detector for Hadron Identification at Jefferson Lab, Hall a

Unambiguous kaon identification is needed for Hypernuclear High Resolution Spectroscopy Experiments in Hall A at Jefferson Lab. Due to the huge pion and proton background, TOF and Areogel threshold detectors are not sufficient. A proximity focusing CsI/freon RICH detector has been designed and built. The tests performed at CBRN showed that the performances are as good as expected. A dedicated CsI evaporation facility, togheter with an on line photocathode QE measurement for mapping out the entire photocathode, has been built and succesfully used.