The ALICE high level trigger
T. Alt, G Grastveit, H. Helstrup, V. Lindenstruth, C. Loizides, Dieter Rohrich, Bernhard Skaali, T. Steinbeck, R. Stock, H. Tilsner, Kjetil Ullaland, Anders Strand Vestbø, T. Vik, Arne Wiebalck · Journal of Physics G Nuclear and Particle Physics · 2004
The ALICE High Level Trigger (HLT) is a computing farm designed and build for the real-time, online processing of the raw data produced by the ALICE detectors. Events are fully reconstructed from the raw data, analyzed and compressed. The analysis summary together with the compressed data and a trigger decision is sent to the DAQ. In addition the reconstruction of the events allows for on-line monitoring of physical observables and this information is provided to the Data Quality Monitor (DQM). The HLT can process event rates of up to 2 kHz for proton-proton and 200 Hz for Pb-Pb central collisions.