Author :
Amaral, P. Borrego ; Ellis, N. ; Farthouat, P. ; Gällno, P. ; Haller, J. ; Krasznahorkay, A. ; Maeno, T. ; Pauly, T. ; Lima, H.P. ; Arcas, I. Resurreccion ; Schuler, G. ; de Seixas, J.M. ; Spiwoks, R. ; Teixeira, R. Torga ; Wengler, T.
Abstract :
ATLAS is a multi-purpose particle physics detector at CERN´s Large Hadron Collider where two pulsed beams of protons are brought to collision at very high energy. There are collisions every 25 ns, corresponding to a rate of 40 MHz. A three-level trigger system reduces this rate to about 200 Hz while keeping bunch crossings which potentially contain interesting processes. The Level-1 trigger, implemented in electronics and firmware, makes an initial selection in under 2.5 mus with an output rate of less than 100 kHz. A key element of this is the central trigger processor (CTP) which combines trigger information from the calorimeter and muon trigger processors to make the final Level-1 accept decision in under 100 ns on the basis of lists of selection criteria, implemented as a trigger menu. Timing and trigger signals are fanned out to all sub-detectors, while busy signals from all sub-detector read-out systems are collected and fed into the CTP in order to throttle the generation of Level-1 triggers
Keywords :
muon detection; nuclear electronics; particle calorimetry; particle detectors; proton detection; trigger circuits; ATLAS Level-1 central trigger processor; CERN; Large Hadron Collider; calorimeter; multipurpose particle physics detector; muon trigger processor; sub-detectors; Colliding beam devices; Electrons; Large Hadron Collider; Mesons; Microprogramming; Particle beams; Physics; Protons; Signal generators; Timing;
