Speaker
David Berge
(CERN)
Description
The ATLAS detector at CERN’s Large Hadron Collider will be exposed to
proton-proton collisions from beams crossing at 40 MHz. A three-level trigger
system will select potentially interesting events in order to reduce this rate
to about 200 Hz. The first trigger level (LVL1) is implemented in custombuilt
electronics and firmware. A trigger decision is made by the LVL1 Central
Trigger Processor (CTP) reducing the incoming rate to less than 100 kHz.
The total allowed latency including cable delays of the round trip from the
detector systems to the CTP and back is less than 2.5μs. The LVL1 decision
is based on Calorimeter information and hits in dedicated Muon Trigger
detectors. The final LVL1 trigger system is currently being installed in the
experiment with an expected date for completion of August 2007. Cosmic-
ray data are regularly recorded as an increasing fraction of the trigger
system comes online. We present an overview of the LVL1 trigger system
and report on the current status, including the commissioning process at
the ATLAS experimental site. Emphasis is put on the integration of the CTP
with the Calorimeter and Muon Trigger systems and the level-2 trigger.
Moreover, we show analysis results of cosmic-ray data recorded in situ and
verify, where possible, that the LVL1 trigger meets the requirements and
will be ready for data taking.
Author
David Berge
(CERN)
