BaBar vs SuperB: Possible strategies for trigger implementations

The SuperB flagship project has recently been approved by INFN director's board. The experiment will be built on a e+e− collider which will deliver about 100 a−1 barn in 5 years with a peak luminosity in the range of 1036 cm−2s−1. Luminosity and trigger rates are 100 times higher than the ones achieved at PEP-II at SLAC for the Babar experiment. Exploiting the measured rates from Babar we can expect when running at 1036 cm−2s−1 : 50 kHz Bhabha, 25 kHz beam background, 25 kHz physics. The trigger must therefore cope with a maximum rate in the range of 150 kHz with an event size of the order of 75 kBytes. A maximum of 70 ns per event dead time is therefore tolerable in order to achieve a maximum event loss of about 1%. As in Babar the most important detectors taking part to the trigger decision will be the Drift Chamber and the electromagnetic calorimeter. This is a real challenge since both the Barrel Calorimeter (CsI Tl doped) and the Drift Chamber are rather slow detectors. In this presentation we review the Babar trigger architecture: its baseline design and the one presently envisaged for SuperB are compared, highlighting the improvements needed to fulfill the research program.