The Level 0 trigger for the DO detector

The DO detector has completed its first data taking run at the Fermi National Accelerator Laboratory's p~-p Tevatron collider. The Level 0 trigger system is the DO experiment's first trigger level used to identify colliding beam crossings containing interactions. It consists of two hodoscopes of scintillation tiles located just outside the DO central tracking region. The Level 0 trigger provides a fast measurement of the interaction position along the beam axis for use in early trigger decisions. A slower, more accurate position of the interaction and an indication of the occurrence of multiple interactions are available for subsequent trigger decisions. In addition, the Level 0 trigger is used as a luminosity monitor for DO. Results on the performance of the Level 0 trigger are presented.<
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