The New DØ Level-1 Calorimeter Trigger

With increasing Tevatron luminosity, efficient triggers that meet the bandwidth limitations of the experiment's data acquisition system become more and more difficult to construct. To meet these challenges, the DOslash experiment has significantly enhanced its triggering capabilities. A major component of this upgrade is a completely re-designed Level-1 calorimeter trigger (L1Cal). This new system uses novel architecture and algorithms to maintain acceptable background rejection while preserving or even improving signal efficiency at the highest luminositiesforeseen. We describe interesting features of the L1Cal and give highlights from its first few months of operation.