A fast, first level, Rφ hardware trigger for the D0 central fiber tracker using field programmable gate arrays

An Rφ trigger was developed using the eight doublet layers of axial fibers in the new Central Fiber Tracker for the DO Upgrade Detector at Fermilab. This trigger must be formed in less than 500 nsec and distributed to other parts of the detector for a level 1 trigger decision. The high speed is achieved by using massively parallel AND/OR logic realized in state-of-the-art field programmable gate arrays, FPGAs. The programmability of the FPGAs allows corrections to the track roads for the as-built detector and for dynamically changing the transverse momentum threshold. To reduce the number of fake tracks at high luminosity, the narrowest possible roads must be used which pushes the total number of roads into the thousands. Monte Carlo simulations of the track trigger were run to develop the trigger algorithms and a vendor specific commercially available simulator was used to develop and test the FPGA programming