Speaker
Dr
Ralf Spiwoks
(CERN)
Description
The ATLAS Level-1 Central Trigger consists of the Muon-to-Central-Trigger-
Processor Interface (MUCTPI), the Central Trigger Processor (CTP), and the
Timing, Trigger and Control (TTC) partitions of the sub-detectors. The MUCTPI
connects the output of the muon trigger system to the CTP. At every bunch
crossing it receives information on muon candidates from each of the 208 muon
trigger sectors and calculates the total multiplicity for each of six pT
thresholds. The CTP combines information from calorimeter and the MUCTPI
and makes the final Level-1 Accept (L1A) decision on the basis of lists of
selection criteria (trigger menus). The MUCTPI and the CTP provide trigger
summary information to the data acquisition system (DAQ) and the Level-2
trigger for every event selected at the Level-1. They further provide
accumulated and, for the CTP, bunch-by-bunch scaler data for monitoring
of the trigger, detector and beam conditions. The TTC partitions send timing,
trigger and control signals from the CTP to the sub-detectors and receive
busy signals which can throttle the generation of L1As. The Local Trigger
Processors (LTPs) normally receive the TTC signals from the CTP but can
also generate them locally. The LTP interface (LTPIF) modules allow to
connect several LTPs for combined local running.
The MUCTPI, the CTP and most of the TTC partitions of the ATLAS sub-detectors
have been installed in the ATLAS experiment and are being used for commissioning
tests with the trigger processors on the input and several sub-detectors
as well as DAQ and Level-2 trigger on the output. Results of operating the
Central Trigger in the experiment using trigger information from trigger
processors connected to sub-detectors observing cosmic rays will be shown.
Authors
Mr
Andrea Messina
Mr
Attila KRASZNAHORKAY
(CERN and Univeristy of Debrecen)
Mr
Christian Ohm
(CERN)
Mr
David Berge
(CERN)
Mr
Georges Schuler
(CERN)
Mr
Herman Pessoa Lima Jr.
(University of Rio de Janeiro)
Mr
Jose de Seixas
(University of Rio de Janeiro)
Mr
Marcelo Perantoni
(University of Rio de Janeiro)
Mr
Nick Ellis
(CERN)
Mr
Per Gallno
(CERN)
Mr
Per Klofver
(CERN)
Mr
Philippe Farthouat
(CERN)
Dr
Ralf Spiwoks
(CERN)
Mr
Stefan Ask
(CERN)
Mr
Stefan Haas
(CERN)
Mr
Thilo Pauly
(CERN)
Mr
Thorsten Wengler
(University of Manchester)
