학술논문

First data with the ATLAS Level-1 Calorimeter Trigger
Document Type
Conference
Source
2008 IEEE Nuclear Science Symposium Conference Record Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE. :1851-1858 Oct, 2008
Subject
Nuclear Engineering
Power, Energy and Industry Applications
Fields, Waves and Electromagnetics
Engineered Materials, Dielectrics and Plasmas
Signal Processing and Analysis
Bioengineering
Large Hadron Collider
System testing
Logic
Field programmable gate arrays
Delay
Physics
Detectors
Performance evaluation
Performance analysis
Mesons
Language
ISSN
1082-3654
Abstract
The ATLAS Level-1 Calorimeter Trigger is one of the main elements of the first stage of event selection for the ATLAS experiment at the LHC. The input stage consists of a mixed analogue/digital component taking trigger sums from the ATLAS calorimeters. The trigger logic is performed in a digital, pipelined system with several stages of processing, largely based on FPGAs, which perform programmable algorithms in parallel with a fixed latency to process about 300 Gbyte/s of input data. The real-time output consists of counts of different types of physics objects, and energy sums. The final system consists of over 300 custom-built VME modules, of several different types. The installation at ATLAS of these modules, and the necessary infrastructure, was completed at the end of 2007. The system has since undergone intensive testing, both in standalone mode, and in conjunction with the whole of the ATLAS detector in combined running. The final steps of commissioning, and experience with running the full-scale system are presented. Results of integration tests performed with the upstream calorimeters, and downstream trigger and data-flow systems, are shown, along with an analysis of the performance of the calorimeter trigger in full ATLAS data-taking. This includes trigger operation during the cosmic muon runs from before LHC start-up, and a first look at LHC proton beam data.