The ATLAS Level-1 Calorimeter Trigger: PreProcessor implementation and performance

• Published in: Journal of instrumentation 2012-12, Vol.7 (12), p.P12008-P12008, Article P12008
• Main Authors: Åsman, B, Achenbach, R, Allbrooke, B M M, Anders, G, Andrei, V, Büscher, V, Bansil, H S, Barnett, B M, Bauss, B, Bendtz, K, Bohm, C, Bracinik, J, Brawn, I P, Brock, R, Buttinger, W, Caputo, R, Caughron, S, Cerrito, L, Charlton, D G, Childers, J T, Curtis, C J, Daniells, A C, Davis, A O, Davygora, Y, Dorn, M, Eckweiler, S, Edmunds, D, Edwards, J P, Eisenhandler, E, Ellis, K, Ermoline, Y, Föhlisch, F, Faulkner, P J W, Fedorko, W, Fleckner, J, French, S T, Gee, C N P, Gillman, A R, Goeringer, C, Hülsing, T, Hadley, D R, Hanke, P, Hauser, R, Heim, S, Hellman, S, Hickling, R S, Hidvégi, A, Hillier, S J, Hofmann, J I, Hristova, I, Ji, W, Johansen, M, Keller, M, Khomich, A, Kluge, E -E, Koll, J, Laier, H, Landon, M P J, Lang, V S, Laurens, P, Lepold, F, Lilley, J N, Linnemann, J T, Müller, F, Müller, T, Mahboubi, K, Martin, T A, Mass, A, Meier, K, Meyer, C, Middleton, R P, Moa, T, Moritz, S, Morris, J D, Mudd, R D, Narayan, R, Nedden, M zur, Neusiedl, A, Newman, P R, Nikiforov, A, Ohm, C C, Perera, V J O, Pfeiffer, U, Plucinski, P, Poddar, S, Prieur, D P F, Qian, W, Rieck, P, Rizvi, E, Sankey, D P C, Schäfer, U, Scharf, V, Schmitt, K, Schröder, C, Schultz-Coulon, H -C, Schumacher, C, Schwienhorst, R, Silverstein, S B, Simioni, E, Snidero, G
• Format: Article
• Language: English
• Subjects: Deposition; Digital; Division; Front-end electronics for detector readout; Hardware; Instrumentation; Modular electronics; Processors; Time measurements; Towers; Trigger algorithms; Trigger concepts and systems (hardware and software)
• ISSN: 1748-0221; 1748-0221
• DOI: 10.1088/1748-0221/7/12/P12008

The PreProcessor system of the ATLAS Level-1 Calorimeter Trigger (L1Calo) receivesabout 7200 analogue signals from the electromagnetic and hadronic components of thecalorimetric detector system. Lateral division results in cells which are pre-summed to so-called Trigger Towers of size 0.1 x 0.1 along azimuth ( phi ) and pseudorapidity ( eta ). The received calorimetersignals represent deposits of transverse energy. The system consists of 124 individual PreProcessor modules that digitise the input signalsfor each LHC collision, and provide energy and timing information to the digital processors of the L1Calo system, which identify physics objects forming much of the basis for the full ATLAS first level trigger decision. This paper describes the architecture of the PreProcessor, its hardware realisation, functionality, and performance.