A Report on the Design and Construction of Sumbox: A Level 1 Trigger for CDF at Fermilab

Sumbox is the end point of level 1 calorimetry trigger at the Collider Detector at Fermilab (CDF), though the final level 1 decision is made by another logic board which considers both calorimetry triggers and other triggers. The total energies (linear or weighted) deposited on the entire detector are summed here, and compared with preset thresholds to make level 1 calorimetry decisions. Sumbox is a fastbus slave implemented with geographical and logical addressing, secondary address and random data cycles, and various responses to incorrect internal addresses and imprudent accesses. Its summing and comparing can be fully tested via fastbus.