John Renner Hansen
Niels Bohr Institute
Copenhagen
On behalf on the Second Level Trigger Group in ATLAS
Abstract
The design of the second level trigger for the ATLAS detector at
the LHC, is based on the assumptions that the first level trigger
will accept 10^5 events per second and that the event builder and
third level trigger system can sustain a event rate of 1000 Hz.
To achieve the necessary event reduction of 100, it is suggested to use a combination of local data processing and global pattern recognition, based on the features found by the local processors.
Different architectural models has been developed based on data driven processors and farms of RISC processors connected through networks, such as ATM, SCI, DS-links, HS-links or custom designed router modules.
The decision on which architecture and which technologies to use, will be based on results from extensive laboratory and beam tests, together with model simulations, using various commercial and home made tools. These simulations will provide predictions of the behaviour of the full size system, based on results from the smaller prototypes.
A discussion of the system requirements, the basic models and results from simulations of the proposed systems is presented.
John Renner Hansen
Niels Bohr Institute
Blegdamsvej 17
DK-2100 Copenhagen
Email renner@nbi.dk