O2: A novel combined online and offline computing system for the ALICE Experiment after 2018

20th International Conference on Computing in High Energy and Nuclear Physics

物理学;计算机科学

Ananya, A.^17 ; Do Passo Suaide, A. Alarcon^22 ; Alves Garcia Prado, C.^22 ; Alt, T.^5 ; Aphecetche, L.^27 ; Agrawal, N.^17 ; Avasthi, A.^17 ; Bach, M.^5 ; Bala, R.^21 ; Barnafoldi, G.^2 ; Bhasin, A.^21 ; Belikov, J.^15 ; Bellini, F.^10 ; Betev, L.^1 ; Breitner, T.^5,9 ; Buncic, P.^1 ; Carena, F.^1 ; Carena, W.^1 ; Chapeland, S.^1 ; Barroso, V. Chibante^1 ; Cliff, F.^1 ; Costa, F.^1 ; Mendez, L. Cunqueiro^1 ; Dash, S.^17 ; Delort, C.^1,7 ; Denes, E.^2 ; Divia, R.^1 ; Doenigus, B.^8 ; Engel, H.^9 ; Eschweiler, D.^5 ; Fuchs, U.^1 ; Gheata, A.^1 ; Gheata, M.^11 ; Ramirez, A. Gomez^9 ; Gorbunov, S.^5 ; Graczykowski, L.^16 ; Grigoras, A.^1 ; Grigoras, C.^1 ; Grigore, A.^1,3 ; Grosso, R.^14 ; Guernane, R.^29 ; Gupta, A.^21 ; Hrivnacova, I.^19 ; Hristov, P.^1 ; Ionita, C.^1 ; Ivanov, M.^8 ; Janik, M.^16 ; Kalcher, S.^5 ; Kassalias, N.^22 ; Kebschull, U.^9 ; Khandelwal, R.^17 ; Kushpil, S.^25 ; Kisel, I.^5 ; Kiss, T.^2,4 ; Kollegger, T.^5 ; Kowalski, M.^28 ; Kretz, M.^5 ; Kulakov, I.^9 ; Lafage, V.^19 ; Lara, C.^9 ; Legrand, I.^13 ; Lindenstruth, V.^5 ; Maevskaya, A.^26 ; Malzacher, P.^8 ; Morsch, A.^1 ; Nandi, B.^17 ; Niculescu, M.^11 ; Pillot, P.^27 ; Planinic, M.^20 ; Pluta, J.^16 ; Poljak, N.^18 ; Rajput, S.^21 ; Read, K.^24 ; Ribon, A.^1 ; Rohr, D.^5 ; Rubin, G.^2 ; Shahoyan, R.^1 ; Sharma, A.^21 ; Simonetti, G.^1,6 ; Smorholm, O.^23 ; Soós, C.^1 ; Szymanski, M.^16 ; Telesca, A.^1 ; Thaeder, J.^8 ; Udupa, A.^17 ; Vyvre, P. Vande^1 ; Vennedey, F.^5,9 ; Von Haller, B.^1 ; Wenzel, S.^1 ; Zampolli, C.^12 ; Zyzak, M.^9

European Organization for Nuclear Research (CERN), Geneva, Switzerland^1

Wigner RCP Hungarian Academy of Sciences, Budapest, Hungary^2

Politehnica University of Bucharest, Bucharest, Romania^3

Cerntech Ltd., Budapest, Hungary^4

Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität, Frankfurt, Germany^5

Dipartimento Interateneo di Fisica M. Merlin, Bari, Italy^6

Ministère des Affaires Etrangères et Européennes, Paris, France^7

GSI-Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt, Germany^8

Institut für Informatik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany

(10) Dipartimento di Fisica e Astronomia, DellUniversit'a and Sezione INFN, Bologna, Italy

(11) ISS-Institute of Space Science, Bucharest, Romania

(12) INFN, University, Italy

(13) California Institute of Technology, Pasadena

CA, United States

(14) University of Houston, United States, Houston

TX, United States

(15) Institut Pluridisciplinaire Hubert Curien, Strasbourg, France

(16) Warsaw University of Technology, Warsaw, Poland

(17) IIT- Indian Institute of Technology, Mumbai, India

(18) Institute Rudjer Boskovic, Zagreb, Croatia

(19) Institut de Physique Nucleaire (IPNO), Universite Paris-Sud, CNRS-IN2P3, Orsay, France

(20) University of Zagreb, Zagreb, Croatia

(21) University of Jammu, Jammu, India

(22) University of São Paulo, Brazil

(23) University of Birmingham, Birmingham, United Kingdom

(24) Oak Ridge National Laboratory, Oak Ridge

TN, United States

(25) Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez u Prahy, Czech Republic

(26) Institute for Nuclear Research, Academy of Sciences, Moscow, Russia

(27) Laboratoire de Physique Subatomique et des Technologies Associees-Subatech, Nantes, France

(28) Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland

(29) Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Universite Joseph Fourier, Institut Polytechnique de Grenoble, Grenoble, France^9

关键词: Heavy ion collision;    High-precision measurement;    Inner tracking system;    Large Hadron Collider;    Large ion collider experiments;    On-line computing systems;    Reconstruction algorithms;    Time projection chambers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/513/1/012037/pdf
DOI  :  10.1088/1742-6596/513/1/012037

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

ALICE (A Large Ion Collider Experiment) is a detector dedicated to the studies with heavy ion collisions exploring the physics of strongly interacting nuclear matter and the quark-gluon plasma at the CERN LHC (Large Hadron Collider). After the second long shutdown of the LHC, the ALICE Experiment will be upgraded to make high precision measurements of rare probes at low pT, which cannot be selected with a trigger, and therefore require a very large sample of events recorded on tape. The online computing system will be completely redesigned to address the major challenge of sampling the full 50 kHz Pb-Pb interaction rate increasing the present limit by a factor of 100. This upgrade will also include the continuous un-triggered read-out of two detectors: ITS (Inner Tracking System) and TPC (Time Projection Chamber)) producing a sustained throughput of 1 TB/s. This unprecedented data rate will be reduced by adopting an entirely new strategy where calibration and reconstruction are performed online, and only the reconstruction results are stored while the raw data are discarded. This system, already demonstrated in production on the TPC data since 2011, will be optimized for the online usage of reconstruction algorithms. This implies much tighter coupling between online and offline computing systems. An R&D program has been set up to meet this huge challenge. The object of this paper is to present this program and its first results.