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Hierarchical trigger of the ALICE calorimeters

The trigger of the ALICE electromagnetic calorimeters is implemented in 2 hierarchically connected layers of electronics. In the lower layer, level-0 algorithms search shower energy above threshold in locally confined Trigger Region Units (TRU). The top layer is implemented as a single, global trigg...

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Autores principales: Muller, Hans, Awes, Terry C, Novitzky, Norbert, Kral, Jiri, Rak, Jan, Schambach, Joachim, Wang, Ya-Ping, Wang, Dong, Zhou, Daicui
Lenguaje:eng
Publicado: 2010
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.nima.2009.06.097
http://cds.cern.ch/record/1290346
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author Muller, Hans
Awes, Terry C
Novitzky, Norbert
Kral, Jiri
Rak, Jan
Schambach, Joachim
Wang, Ya-Ping
Wang, Dong
Zhou, Daicui
author_facet Muller, Hans
Awes, Terry C
Novitzky, Norbert
Kral, Jiri
Rak, Jan
Schambach, Joachim
Wang, Ya-Ping
Wang, Dong
Zhou, Daicui
author_sort Muller, Hans
collection CERN
description The trigger of the ALICE electromagnetic calorimeters is implemented in 2 hierarchically connected layers of electronics. In the lower layer, level-0 algorithms search shower energy above threshold in locally confined Trigger Region Units (TRU). The top layer is implemented as a single, global trigger unit that receives the trigger data from all TRUs as input to the level-1 algorithm. This architecture was first developed for the PHOS high pT photon trigger before it was adopted by EMCal also for the jet trigger. TRU units digitize up to 112 analogue input signals from the Front End Electronics (FEE) and concentrate their digital stream in a single FPGA. A charge and time summing algorithm is combined with a peakfinder that suppresses spurious noise and is precise to single LHC bunches. With a peak-to-peak noise level of 150 MeV the linear dynamic range above threshold spans from MIP energies at 215 up to 50 GeV. Local level-0 decisions take less than 600 ns after LHC collisions, upon which all TRUs transfer their level-0 trigger data to the upstream global trigger module which searches within the remaining level-1 latency for high pT gamma showers (PHOS) and/or for Jet cone areas (EMCaL).
id cern-1290346
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2010
record_format invenio
spelling cern-12903462019-09-30T06:29:59Zdoi:10.1016/j.nima.2009.06.097http://cds.cern.ch/record/1290346engMuller, HansAwes, Terry CNovitzky, NorbertKral, JiriRak, JanSchambach, JoachimWang, Ya-PingWang, DongZhou, DaicuiHierarchical trigger of the ALICE calorimetersDetectors and Experimental TechniquesThe trigger of the ALICE electromagnetic calorimeters is implemented in 2 hierarchically connected layers of electronics. In the lower layer, level-0 algorithms search shower energy above threshold in locally confined Trigger Region Units (TRU). The top layer is implemented as a single, global trigger unit that receives the trigger data from all TRUs as input to the level-1 algorithm. This architecture was first developed for the PHOS high pT photon trigger before it was adopted by EMCal also for the jet trigger. TRU units digitize up to 112 analogue input signals from the Front End Electronics (FEE) and concentrate their digital stream in a single FPGA. A charge and time summing algorithm is combined with a peakfinder that suppresses spurious noise and is precise to single LHC bunches. With a peak-to-peak noise level of 150 MeV the linear dynamic range above threshold spans from MIP energies at 215 up to 50 GeV. Local level-0 decisions take less than 600 ns after LHC collisions, upon which all TRUs transfer their level-0 trigger data to the upstream global trigger module which searches within the remaining level-1 latency for high pT gamma showers (PHOS) and/or for Jet cone areas (EMCaL).oai:cds.cern.ch:12903462010
spellingShingle Detectors and Experimental Techniques
Muller, Hans
Awes, Terry C
Novitzky, Norbert
Kral, Jiri
Rak, Jan
Schambach, Joachim
Wang, Ya-Ping
Wang, Dong
Zhou, Daicui
Hierarchical trigger of the ALICE calorimeters
title Hierarchical trigger of the ALICE calorimeters
title_full Hierarchical trigger of the ALICE calorimeters
title_fullStr Hierarchical trigger of the ALICE calorimeters
title_full_unstemmed Hierarchical trigger of the ALICE calorimeters
title_short Hierarchical trigger of the ALICE calorimeters
title_sort hierarchical trigger of the alice calorimeters
topic Detectors and Experimental Techniques
url https://dx.doi.org/10.1016/j.nima.2009.06.097
http://cds.cern.ch/record/1290346
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