Design and Test of the Off-Detector Electronics for the CMS Barrel Muon Trigger

Drift Tubes chambers are used in the CMS barrel for tagging the passage of high Pt muons generated in a LHC event and for triggering the CMS data read out. The Sector Collector (SC) system synchronizes the track segments built by trigger modules on the chambers and deliver them to reconstruction processors (Track Finder, TF) that assemble full muon tracks. Then, the Muon Sorter (MS) has to select the best four candidates in the barrel and to filter fake muons generated by the TF system redundancy. The hardware implementations of the Sector Collector and Muon Sorter systems satisfy radiation, I/O and fast timing constraints using several FPGA technologies. The hardware was tested with custom facilities, integrated with other trigger subsystems, and operated in a beam test. A test beam on a 40 MHz bunched beam validated the local trigger electronics and off-detector prototype cards and the synchronization tools. The CMS Magnet Test and Cosmic challenge in 2006 proved stable and reliable operation of the Drift Tubes trigger and its integration with other trigger systems and with the readout system. Constraints, design, test and operation of the modules are presented.