Sep 20 – 24, 2010
Aachen, Germany
Europe/Zurich timezone

Development and Online Operation of Minimum Bias Triggers in ATLAS

Sep 23, 2010, 4:00 PM


Poster Trigger POSTERS Session


Mr Tim Martin (University of Birmingham, UK)


The design of minimum bias triggers should allow for a highly efficient selection on pp-collisions, while minimising any possible bias in the event selection. In ATLAS two main minimum bias triggers have been developed using complementary technologies. A hardware based first level trigger, consisting of 32 plastic scintillators, has proven to efficienctly select pp-interactions. In particular during the start-up phase this trigger played a crucial role for the commissioning of the central trigger processor and detector sub-systems. A complementary selection is achieved by a multi-level minimum bias trigger, seeded off a random trigger on filled bunches. For the event selection at higher trigger levels a dedicated algorithm was developed, able to cope with around 86 millions of detector signals per bunch-crossing. We will present these trigger systems and their deployment online, highlighting their performance and trigger efficiencies. We outline as well the operation with increasing beam intensities and luminosities.

Primary author

Ms Regina Kwee (for the ATLAS Collaboration)

Presentation materials