The multilevel trigger system of the DIRAC experiment
/ Authors
L.Afanasyev, M.Gallas, D.Goldin, A.Gorin, V.Karpukhin, P.Kokkas, A.Kulikov, K.Kuroda, I.Manuilov, K.Okada
and 7 more authors
C.Schuetz, A.Sidorov, M.Steinacher, F.Takeutchi, L.Tauscher, S.Vlachos, V.Yazkov
/ Abstract
The multilevel trigger system of the DIRAC experiment at CERN is presented. It includes a fast first level trigger as well as various trigger processors to select events with a pair of pions having a low relative momentum typical of the physical process under study. One of these processors employs the drift chamber data, another one is based on a neural network algorithm and the others use various hit-map detector correlations. Two versions of the trigger system used at different stages of the experiment are described. The complete system reduces the event rate by a factor of 1000, with efficiency ≥ 95% of detecting the events in the relative momentum range of interest.