TY - JOUR
T1 - The ZEUS calorimeter first level trigger
AU - Silverstein, S.
AU - Ali, I.
AU - Behrens, B.
AU - Foudas, C.
AU - Fordham, C.
AU - Goussiou, A.
AU - Jaworski, M.
AU - Lackey, J.
AU - Reeder, D.
AU - Robl, P.
AU - Smith, W. H.
AU - Vaiciulis, A.
AU - Wodarczyk, M.
AU - Dawson, J.
AU - Krakauer, D.
AU - Talaga, R.
AU - Schlereth, J.
AU - Zhang, H.
N1 - Funding Information:
This work is supportedb y the DOE, under contractn o. DE-AE02-76ER0881.
PY - 1995/6/1
Y1 - 1995/6/1
N2 - An overview of the ZEUS calorimeter first level trigger is presented. The CFLT uses a pipelined architecture to accept and analyze calorimeter data for every 96 ns beam crossing interval. PMT signals are combined by analog electronics into electromagnetic and hadronic sums for 896 trigger towers. The analog sums are then digitized and analyzed. The CFLT determines the total, transverse, and missing transverse energy, identifies isolated electrons and muons, and sums energies in programmable subregions. Calculations are performed in 96 ns steps, and new data are accepted for every beam crossing. Trigger data are forwarded to the global first level trigger (GFLT) after 2 μs, allowing a GFLT accept to be issued 5 μs after the beam crossing which produced the event. Important features of the CFLT include a 12-bit effective dynamic range, extensive use of memory lookup tables for trigger calculations, fast pattern searches for isolated leptons, and low electronics noise. During the 1993 HERA run, the CFLT reduced a 50 kHz background rate to around 100 Hz.
AB - An overview of the ZEUS calorimeter first level trigger is presented. The CFLT uses a pipelined architecture to accept and analyze calorimeter data for every 96 ns beam crossing interval. PMT signals are combined by analog electronics into electromagnetic and hadronic sums for 896 trigger towers. The analog sums are then digitized and analyzed. The CFLT determines the total, transverse, and missing transverse energy, identifies isolated electrons and muons, and sums energies in programmable subregions. Calculations are performed in 96 ns steps, and new data are accepted for every beam crossing. Trigger data are forwarded to the global first level trigger (GFLT) after 2 μs, allowing a GFLT accept to be issued 5 μs after the beam crossing which produced the event. Important features of the CFLT include a 12-bit effective dynamic range, extensive use of memory lookup tables for trigger calculations, fast pattern searches for isolated leptons, and low electronics noise. During the 1993 HERA run, the CFLT reduced a 50 kHz background rate to around 100 Hz.
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U2 - 10.1016/0168-9002(94)01618-6
DO - 10.1016/0168-9002(94)01618-6
M3 - Article
AN - SCOPUS:58149211474
SN - 0168-9002
VL - 360
SP - 322
EP - 324
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
IS - 1-2
ER -