  The CLEO detector will undergo major improvements in conjunction with a high
luminosity upgrade of the CESR electron positron collider, that should increase
the luminosity of this machine by a factor of 10. The most innovative feature
of the planned CLEO detector is the addition of a state of the art particle
identification system, based on a proximity focused Ring Imaging Cherenkov
detector. The goal is to achieve good hadron identification at all the momenta
relevant to the study of decays of B mesons produced at the upsilon(4S)
resonance. This detector design will be discussed, including details of the
mechanical design and the readout electronics. The performance of a prototype
module will be described.
