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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...
Autores principales: | , , , , , , , , |
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Lenguaje: | eng |
Publicado: |
2010
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Materias: | |
Acceso en línea: | https://dx.doi.org/10.1016/j.nima.2009.06.097 http://cds.cern.ch/record/1290346 |
_version_ | 1780920698605142016 |
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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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