Operation of the Upgraded ATLAS Level-1 Central Trigger System

21st International Conference on Computing in High Energy and Nuclear Physics

物理学;计算机科学

Glatzer, Julian^1

CERN European Organization for Nuclear Research, Geneva

1211-23, Switzerland^1

关键词: ATLAS detectors;    ATLAS experiment;    Data acquisition system;    On-line computing systems;    Operational experience;    Operational software;    Physics analysis;    Software frameworks;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/664/8/082013/pdf
DOI  :  10.1088/1742-6596/664/8/082013

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

The ATLAS Level-1 Central Trigger (L1CT) system is a central part of ATLAS data-taking and has undergone a major upgrade for Run 2 of the LHC, in order to cope with the expected increase of instantaneous luminosity of a factor of two with respect to Run 1. The upgraded hardware offers more flexibility in the trigger decisions due to the factor of two increase in the number of trigger inputs and usable trigger channels. It also provides an interface to the new topological trigger system. Operationally - particularly useful for commissioning, calibration and test runs - it allows concurrent running of up to three different subdetector combinations. An overview of the operational software framework of the L1CT system with particular emphasis on the configuration, controls and monitoring aspects is given. The software framework allows a consistent configuration with respect to the ATLAS experiment and the LHC machine, upstream and downstream trigger processors, and the data acquisition system. Trigger and dead-time rates are monitored coherently at all stages of processing and are logged by the online computing system for physics analysis, data quality assurance and operational debugging. In addition, the synchronisation of trigger inputs is watched based on bunch-by-bunch trigger information. Several software tools allow for efficient display of the relevant information in the control room in a way useful for shifters and experts. The design of the framework aims at reliability, flexibility, and robustness of the system and takes into account the operational experience gained during Run 1. The Level-1 Central Trigger was successfully operated with high efficiency during the cosmic-ray, beam-splash and first Run 2 data taking with the full ATLAS detector.