The CLAS at Jefferson Lab is a unique facility for elecro-magnetic nuclear physics worldwide. An important feature of CLAS is its capability to detect nearly the entire phase space of a reaction, simultaneously. Particle identification with CLAS is achieved by the combination of time of-flight from the target to the scintillation counters with momentum measurements in the drift chambers/magnet system. Obtaining the ultimate time resolution from the time-of-flight counters is essential for the separation of charged pions, kaons and protons. A calibration procedure will be described that utilizes the 2 nsec rf structure of the electron beam to obtain uniform timing calibration for the entire time-of-flight system consisting of 288 channels. The calibration is maintained at the 50 psec level. CLAS utilizes the missing mass techniques for the measurement of exclusive final states. CLAS' performance using this technique in combination with charged particle identification will be presented.

maintained by Publications Manager