Real-time data processing in the ALICE High Level Trigger at the LHC

• Published in: Computer physics communications Vol. 242; no. C; pp. 25 - 48
• Main Authors: Acharya, Shreyasi, Acosta, F.T., Adamova, Dagmar, Adhya, Souvik Priyam, Adler, Alexander, Adolfsson, Jonatan, Aggarwal, Madan Mohan, Aglieri Rinella, Gianluca, Agnello, Michelangelo, Ahammed, Zubayer, Ahmad, Shakeel, Ahn, Sang Un, Aiola, Salvatore, Akindinov, Alexander, Al-Turany, Mohammad, Alam, Sk Noor, Silva de Albuquerque, Danilo, Aleksandrov, Dmitry, Alessandro, Bruno, Alfanda, Haidar Mas'Ud, Alfaro Molina, Jose Ruben, Ali, Bushra, Ali, Yasir, Alici, Andrea, Alkin, Anton, Alme, Johan, Alt, Torsten, Altenkamper, Lucas, Altsybeev, Igor, Anaam, Mustafa Naji, Andrei, Cristian, Andreou, Dimitra, Andrews, Harry Arthur, Andronic, Anton, Angeletti, Massimo, Anguelov, Venelin, Anson, Christopher Daniel, Anticic, Tome, Antinori, Federico, Antonioli, Pietro, Anwar, Rafay, Apadula, Nicole, Aphecetche, Laurent Bernard, Appelshaeuser, Harald, Arcelli, Silvia, Arnaldi, Roberta, Arratia Munoz, Miguel Ignacio, Arsene, Ionut Cristian, Arslandok, Mesut, Augustinus, Andre, Averbeck, Ralf Peter, Azmi, Mohd Danish, Badala, Angela, Baek, Yong Wook, Bagnasco, Stefano, Bailhache, Raphaelle Marie, Bala, Renu, Baldisseri, Alberto, Ball, Markus, Baral, Rama Chandra, Barbera, Roberto, Barioglio, Luca, Barnafoldi, Gergely Gabor, Barnby, Lee Stuart, Ramillien Barret, Valerie, Bartalini, Paolo, Barth, Klaus, Bartsch, Esther, Bastid, Nicole, Basu, Sumit, Batigne, Guillaume, Batyunya, Boris, Batzing, Paul Christoph, Bauri, Dibakar, Bazo Alba, Jose Luis, Bearden, Ian Gardner, Bedda, Cristina, Behera, Nirbhay Kumar, Belikov, Iouri, Bellini, Francesca, Bello Martinez, Hector, Bellwied, Rene, Espinoza Beltran, Lucina Gabriela, Belyaev, Vladimir, Bencedi, Gyula, Beole, Stefania, Bercuci, Alexandru, Berdnikov, Yaroslav, Berenyi, Daniel, Bertens, Redmer Alexander, Berzano, Dario, Betev, Latchezar, Bhasin, Anju, Bhat, Inayat Rasool, Bhatt, Himani, Bhattacharjee, Buddhadeb, Bianchi, Antonio, Bianchi, Livio, Bianchi, Nicola, Bielcik, Jaroslav
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 01.09.2019; Elsevier
• Subjects: Computer Science; FPGA; Fysik; GPU; Instrumentation and Detectors; MATHEMATICS AND COMPUTING; Natural Sciences; Naturvetenskap; Physical Sciences; Physics; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Subatomic Physics; Subatomär fysik; FPGA; GPU; data management; performance; ALICE; multiprocessor: graphics; trigger; monitoring; calibration; programming; quality
• ISSN: 0010-4655; 1879-2944
• DOI: 10.1016/j.cpc.2019.04.011

At the Large Hadron Collider at CERN in Geneva, Switzerland, atomic nuclei are collided at ultra-relativistic energies. Many final-state particles are produced in each collision and their properties are measured by the ALICE detector. The detector signals induced by the produced particles are digitized leading to data rates that are in excess of 48GB/s. The ALICE High Level Trigger (HLT) system pioneered the use of FPGA- and GPU-based algorithms to reconstruct charged-particle trajectories and reduce the data size in real time. The results of the reconstruction of the collision events, available online, are used for high level data quality and detector-performance monitoring and real-time time-dependent detector calibration. The online data compression techniques developed and used in the ALICE HLT have more than quadrupled the amount of data that can be stored for offline event processing.