Speaker
Dr
Benedetto Gorini
(CERN)
Description
The Trigger and Data Acquisition system (TDAQ) of the ATLAS experiment at the CERN
Large Hadron Collider is based on a multi-level selection process and a hierarchical
acquisition tree. The system, consisting of a combination of custom electronics and
commercial products from the computing and telecommunication industry, is required to
provide an online selection power of 105 and a total throughput in the range of
Terabit/sec.
The concept and design of the ATLAS TDAQ have been developed to take maximum
advantage of the physics nature of very high-energy hadron interactions. The trigger
system is implemented to provide a background rejection of one to two orders of
magnitude before the events are fully reconstructed. The Region-of-Interest (RoI)
mechanism is used to minimise the amount of data needed to calculate the trigger
decisions thus reducing the overall network data traffic considerably. The final
system will consist of a few thousands processors, interconnected by multi-layer Gbit
Ethernet networks. The selection and data acquisition software has been designed
in-house, based on industrial technologies (such as CORBA, CLIPS and Oracle).
Software releases are produced on a regular basis and exploited on a number of test
beds as well as for detector data taking in test labs and test beams.
This paper introduces the basic system requirements and concepts. describes the
architecture and design of the system and reports on the actual status of
construction. It serves as introduction to the functionally and performance
measurements made on large-scale test systems (LST) and on the TDAQ Pre-series
installation, reported in separate papers at this conference.
Author
Dr
Livio Mapelli
(CERN)
