Sector Logic FPGA demonstrator simulation , implementation and tests

DRAFT This document has not been approved and may contain factual errors. Abstract Abstract here. To change document date, double click on the date above. Sector Logic FPGA demonstrator simulation, implementation and tests ATL-T/DAQ-xxx-00 ATLAS Muon 22 May 2000 2 1 Introduction Document History 1 Introduction The first level muon trigger for the barrel in ATLAS is based on fast geometric coincidence between the various planes of the muon spectrometer surrounding the detector. In order to perform the trigger algorithm special dedicated detectors (RPC, Resistive Plate Chambers) with digital readout and with a spatio-temporal resolution of 1 cm x 1 ns are used. The algorithm is performed separately in η and φ in order to reduce the fake trigger rate due to the background. The trigger chambers are arranged in three different planes from the interaction point, each chamber has four series of strips (two along η and two along φ). There are a total of six planes of RPC strips per view (the number of RPC strips planes is redundant in order to reduce the fake trigger rate due to the background). The trigger algorithm is executed for low and for high P T. • For the low P T algorithm, if a strip is hit in the pivot plane (RPC2) the trigger processor searches for an hit in the first trigger chambers plane (RPC1) looking inside a cone whose axis is on the line that conjuncts the hitted point in RPC2 with the nominal interaction point, whose vertex is on the RPC2 plane and whose opening gives the cut on P T. A valid trigger is generated if RPC1 and RPC2 are hit in coincidence For each threshold it is possible to set a 2/4, 3/4 or 4/4 majority.