The CLAS Cherenkov detector

The design, construction, and performance of the CLAS Chrenkov threshold gas detector at Jefferson Lab is described. The detector consists of 216 optical modules. Each module consists of the of three adjustable mirrors of lightweight composite construction. a Winston light collecting cone, a 5-in. photomiltiplier tube, and specially designed magnetic shielding. Efficiencies and response functions have been measured. (C) 2001 Elsevier Science B.V. All rights reserved.