CERN Accelerating science

ATLAS Note
Report number	ATL-DAQ-95-030 ; RD-27 Note 34 ; ATL-D-PN-30
Title	The level-1 calorimeter trigger system for ATLAS
Author(s)	Brawn, I P (Birmingham U.) ; Carney, R E (Birmingham U.) ; Garvey, J (Birmingham U.) ; Rees, D (Birmingham U.) ; Staley, R J (Birmingham U.) ; Watkins, P M (Birmingham U.) ; Watson, AT (Birmingham U.) ; Ellis, Nick (CERN) ; Geweniger, C (U. Heidelberg (main)) ; Hanke, P (U. Heidelberg (main)) ; Kluge, E E (U. Heidelberg (main)) ; Putzer, A (U. Heidelberg (main)) ; Rensch, B (U. Heidelberg (main)) ; Tittel, K (U. Heidelberg (main)) ; Wunsch, M (U. Heidelberg (main)) ; Eisenhandler, E F (Queen Mary, U. of London) ; Landon, M (Queen Mary, U. of London) ; Pentney, JM (Queen Mary, U. of London) ; Thompson, G (Queen Mary, U. of London) ; Edwards, J (Rutherford) ; Gee, CNP (Rutherford) ; Gillman, A R (Rutherford) ; Hatley, R (Rutherford) ; Leake, J (Rutherford) ; Perera, V J O (Rutherford) ; Shah, TP (Rutherford) ; Sundblad, R (SiCon, Linkoping) ; Appelquist, G (Stockholm U.) ; Bohm, C (Stockholm U.) ; Engström, M (Stockholm U.) ; Hellman, S (Stockholm U.) ; Holmgren, S O (Stockholm U.) ; Johansson, E (Stockholm U.) ; Yamdagni, N (Stockholm U.) ; Zhao, X (Stockholm U.)
Collaboration	RD27
Publication	1995
Imprint	17 Jan 1995
Number of pages	51
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; ATLAS RD27
Abstract	We describe the design of a digital calorimeter trigger processor system which could form a major part of the ATLAS level-1 trigger system. Utilising novel techniques, but with today’s technologies, the system can be contained within six electronics crates and will provide the central trigger logic with signals from events with high-pT electrons, photons, jets and missing ET. Communication with the trigger digitisation system will employ commercial high-speed optical links, terminating in multi-chip modules (MCMs) incorporating custom-designed integrated optics. Simulation studies combined with an extensive demonstrator programme have been used to develop flexible digital algorithms with programmable parameters for bunch-crossing identification and electromagnetic cluster-finding. These algorithms will be embedded in semi-custom application-specific integrated circuits, of which five types will be designed. Inter-crate data fan-out will be achieved by means of optical splitters, while communication within crates will use transmission-line backplanes. The remaining technical issues will be studied in the final phase of the current R&D demonstrator programme. A parallel demonstrator programme is also under way to study alternative techniques with the potential for future system enhancement.
Copyright/License	Preprint: (License: CC-BY-4.0)

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