Slice Test Results of the ATLAS Barrel Muon Level-1 Trigger

The muon spectrometer of the ATLAS experiment makes use of the Resistive Plate Chambers detectors for particle tracking in the barrel region. The level-1 muon trigger system has to measure and discriminate muon transverse momentum, perform a fast and coarse tracking of the muon candidates, associate them to the bunch crossing corresponding to the event of interest, measure the second coordinate in the non-bending projection. The on-detector electronics first collects front-end signals coming from the two inner RPC stations on the low-pT PAD boards, each one covering a region of DetaxDphi=0.2x0.2, and hosting four Coincidence Matrix ASICs. Each CMA performs the low-pT trigger algorithm and data readout on a region of DetaxDphi=0.2x0.1. Data coming from the four CMAs are assembled by the low-pT PAD logic. Each low-pT PAD board sends data to the corresponding high-pT PAD boards, located on the outer RPC station. Four CMA on each board make use of the low-pT trigger result and of the front-end signals coming from the outer RPC stations to perform the high-pT algorithm. The overall results are assembled by the high-pT PAD logic and sent via optical fibre to the off-detector electronics. Each optical receiver board collects data from six or seven fibres, covering a region of DetaxDphi=1.0x0.1. Trigger data are sent to the local Sector Logic, which elaborates trigger data and sends them to the Muon Central Trigger Processor Interface via dedicated copper links. Readout data are sent to the Read-Out Drivers Boards.