An Aerogel RICH Detector for CLAS

In this note the author briefly outlines progress on the design of a ring imaging Cerenkov detector (RICH) utilizing a silica aerogel radiator for integration into the CLAS detector. This detector is used to augment particle identification in the CLAS detector when operating with higher energy electron beams. At increased JLAB energy there is a need for additional particle identification beyond the current CLAS capability. In particular, the separation of kaons from pions using ordinary time of flight becomes less useful for momenta much greater than 2 GeV/c, whereas for an incident energy of 10 GeV the momentum of produced kaons within the CLAS acceptance is greater than 6 GeV/c. In order to achieve this separation two types of Cerenkov techniques, threshold and ring imaging (RICH), have been commonly applied. Recently, there have been technological developments which have simplified the technology of RICH detectors and opened up the potential for their more common use. First, the quality of silica aerogel has been improved in the light transparency and index of refraction (n) variability so that they have been shown to be useful Cerenkov Radiators. Second, techniques for detecting the rings of Cerenkov light with good resolution are being developed