CERN Accelerating science

Article
Title	The data acquisition system for the CMS experiment at the LHC
Author(s)	Antchev, G ; Berti, L ; Cano, E ; Cittolin, Sergio ; Erhan, S ; Gigi, D ; Gutleber, J ; Jacobs, C ; Maron, G ; Meijers, F ; Meschi, E ; Ninane, A ; Orsini, L ; Oh, A ; Pollet, L ; Rácz, A ; Samyn, D ; Scharff-Hansen, P ; Schwick, C ; Sphicas, Paris
Affiliation	(CERN) ; (INFN, Legnaro) ; (MIT, MA, USA) ; (Univ. Catholique Louvain, Belgium) ; (Univ. California, CA, USA)
Publication	2002
In:	7th International Conference on Advanced Technology and Particle Physics, Como, Italy, 15 - 19 Oct 2001, pp.540-549
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Abstract	The trigger and data acquisition systems will play a key role in experiments at the Large Hadron Collider (LHC) currently under construction at CERN. At the LHC, with a beam-crossing frequency of 40 MHz, and a design luminosity of 10/sup 34/ cm/sup -2/ s/sup -1/, an average of 20 inelastic pp events will be produced per crossing. The CMS detector, with more than 10/sup 8/ electronics channels, will produce  1 MB of zero-suppressed data per crossing, so that both the collision and the overall data rates are many orders of magnitude larger than the current goals of storing events at a rate of O(100)Hz at data rates of O(100) MB/s respectively. The CMS trigger and data acquisition system is designed to analyse the detector information at the full crossing rate and to select a maximum of 100 Hz of events to be stored for offline analysis. (10 refs).