The ATLAS level-1 trigger: Status of the system and experience from commissioning with cosmic ray muons

R. Achenbach, P. Adragna, G. Aielli, A. Aloisio, M. G. Alviggi, V. Andrei, S. Antonelli, S. Ask, B. Åsman, O. Bahat Treidel, B. M. Barnett, B. Bauss, L. Bellagamba, S. Ben Ami, M. Bendel, Y. Benhammou, D. Berge, M. Bianco, M. G. Biglietti, C. BohmJ. R.A. Booth, D. Boscherini, I. P. Brawn, S. Bressler, A. Bruni, G. Bruni, S. Buda, P. Camarri, V. Canale, D. Caracinha, R. Cardarelli, G. Carlino, D. G. Charlton, G. Chiodini, G. Ciapetti, N. J. Collins, M. R. Coluccia, S. Constantin, F. Conventi, C. J. Curtis, A. O. Davis, D. De Pedis, J. M. De Seixas, R. DeAsmundis, M. DellaPietra, D. DellaVolpe, A. Di Girolamo, A. Di Mattia, A. DiCiaccio, M. Dogaru, S. Eckweiler, W. Ehrenfeld, E. Eisenhandler, N. Ellis, E. Etzion, P. Farthouat, P. J.W. Faulkner, J. Fleckner, F. Föhlisch, C. Fukunaga, P. Gällnö, C. N.P. Gee, C. Geweniger, A. R. Gillman, P. Giusti, E. Gorini, F. Grancagnolo, S. Haas, J. Haller, P. Hanke, Y. Hasegawa, S. J. Head, S. Hellman, A. Hidvégi, S. J. Hillier, G. Iacobucci, P. Iengo, M. Ikeno, M. Ishino, H. Iwasaki, V. Izzo, M. Johansen, T. Kadosaka, E. Kajomovitz, N. Kanaya, K. Kawagoe, T. Kawamoto, H. Kiyamura, P. Klofver, E. E. Kluge, T. Kobayashi, A. Krasznahorkay, T. Kubota, H. Kurashige, T. Kuwabara, M. Landon, D. Lellouch, V. Lendermann, L. Levinson, B. Liberti, R. Lifshitz, J. N. Lilley, C. Luci, N. Lupu, K. Mahboubi, G. Mahout, F. Marchese, K. Meier, A. Messina, A. Migliaccio, G. Mikenberg, T. Moa, K. Nagano, A. Neusiedl, A. Nisati, T. Niwa, M. Nomachi, H. Nomoto, M. Nozaki, A. Ochi, C. Ohm, Y. Okumura, B. Oltmann, C. Omachi, H. Oshita, E. Pasqualucci, F. Pastore, S. Patricelli, T. Pauly, M. Pectu, M. Perantoni, V. J.O. Perera, R. Perrino, H. Pessoa Lima, E. Petrolo, A. Polini, D. P.F. Prieur, M. Primavera, W. Qian, S. Rieke, A. Roich, S. Rosati, F. Rühr, H. Sakamoto, A. Salamon, D. P.C. Sankey, R. Santonico, O. Sasaki, U. Schäfer, K. Schmitt, G. Schuler, H. C. Schultz-Coulon, G. Sekhniaidze, S. Silverstein, E. Solfaroli, S. Spagnolo, F. Spila, R. Spiwoks, R. J. Staley, R. Stamen, M. C. Stockton, Y. Sugaya, T. Sugimoto, Y. Takahashi, H. Takeda, T. Takeshita, S. Tanaka, S. Tapprogge, S. Tarem, J. P. Thomas, M. Tomoto, T. Trefzger, R. Vari, S. Veneziano, P. M. Watkins, A. Watson, P. Weber, T. Wengler, E. E. Woehrling, Y. Yamaguchi, Y. Yasu, L. Zanello

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting events in order to reduce this rate to 100-200 Hz. A trigger decision is made by the Level-1 Central Trigger Processor (CTP) reducing the incoming rate to less than 100 kHz. The Level-1 decision is based on Calorimeter information and hits in dedicated Muon Trigger detectors. The final Level-1 trigger system is currently being installed in the experiment with completion expected in autumn 2007. Cosmic ray data are regularly recorded as an increasing fraction of the trigger system comes online. We present an overview of the Level-1 trigger system architecture and report on the installation and commissioning process at the ATLAS experimental site. Emphasis is put on the integration of the CTP with the Calorimeter and Muon Trigger systems. We show results from analyses of cosmic ray data recorded in situ and verify, where possible, that the Level-1 trigger meets the requirements and will be ready for data taking.

Original languageEnglish
Title of host publication2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages7
ISBN (Print)1424409233, 9781424409235
Publication statusPublished - 2007
Externally publishedYes
Event2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC - Honolulu, HI, United States
Duration: Oct 27 2007Nov 3 2007

Publication series

NameIEEE Nuclear Science Symposium Conference Record
ISSN (Print)1095-7863


Other2007 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC
Country/TerritoryUnited States
CityHonolulu, HI

All Science Journal Classification (ASJC) codes

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging


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