Author :
Bruinsma, M. ; Fleckenstein, H. ; Gerndt, E.K.E. ; Flammer, J. ; Michetti, A. ; Negri, I. ; Nörenberg, M. ; Ressing, D. ; Riu, I. ; Rothe, C. ; Somov, A. ; Gläss, J. ; Gröpel, A. ; Hähnel, C. ; Männer, R. ; Pernack, R. ; Popov, V. ; Schwingenheuer, B.
Abstract :
Hera-B is a fixed target experiment using a halo target inside the HERA proton ring to generate B mesons in 920 GeV proton-nucleus interactions. The first-level trigger (FLT) of the experiment has to reduce the primary 10-MHz input rate by a factor 200 in less than 10 μs to make it acceptable to the second level trigger (SLT). The trigger strategy is based on the tracking of charged particles and on the reconstruction of their kinematic parameters. The combination of track pairs can also be used for the final decision. A parallel and pipelined set of approximately 60 dedicated boards was designed and built to perform this job. In this paper, the working principle of the system and some results obtained by analyzing the data collected during the run in the year 2000 are described
Keywords :
Cherenkov counters; data acquisition; muon detection; nuclear electronics; particle calorimetry; position sensitive particle detectors; proton accelerators; silicon radiation detectors; storage rings; transition radiation detectors; trigger circuits; 10 MHz; 10 mus; 920 GeV; B meson production; HERA proton ring; Hera-B; RICH; Si; charged particle tracking; dedicated boards; electromagnetic calorimeter; first-level trigger; fixed target experiment; hadronic event rate; halo target; kinematic parameters; latency; muon detector; proton-nucleus interactions; reconstruction; ring image Cherenkov detector; second level trigger; silicon vertex detector; spectrometer magnet; track finding; transition radiation detector; Data analysis; Delay; Electromagnetic radiation; Job design; Kinematics; Mesons; Particle tracking; Protons; Radiation detectors; Silicon radiation detectors;
