CLEO III operation

One year after the installation of most of the components of CLEO III, a strongly upgraded successor to the successful CLEO phase I and II experiments, and about half a year after its completion by the installation of the Silicon Detector, the experiment has successfully passed its commissioning phase and completed its first data-taking period. Major components of the detector upgrade are a new Drift Chamber with improved material distribution and a reduced volume to accommodate focussing accelerator components and the new particle identification system, a new four-layer Silicon Detector integrated in the overall tracking system to compensate for the reduced tracking volume and a proximity-focussing RICH with solid LiF crystal radiators and multi-wire proportional chambers filled with CH4/triethylamine. Preliminary performance benchmark studies have been completed and show that the CLEO III upgrade has been successful in achieving its design goals.