ATLAS DataFlow: the read-out subsystem, results from trigger and data-acquisition system testbed studies and from modeling

Author

Vermeulen, J. ; Abolins, M. ; Alexandrov, I. ; Amorim, A. ; Anjos, A. Dos ; Badescu, E. ; Barros, N. ; Beck, H.P. ; Blair, R. ; Burckhart-Chromek, D. ; Caprini, M. ; Ciobotaru, M. ; Corso-Radu, A. ; Cranfield, R. ; Crone, G. ; Dawson, J. ; Dobinson, R. ;

Author_Institution

NIKHEF, Amsterdam, Netherlands

Volume

53

Issue

3

fYear

2006

fDate

6/1/2006 12:00:00 AM

Firstpage

912

Lastpage

917

Abstract

In the ATLAS experiment at the LHC, the output of read-out hardware specific to each subdetector will be transmitted to buffers, located on custom made PCI cards ("ROBINs"). The data consist of fragments of events accepted by the first-level trigger at a maximum rate of 100 kHz. Groups of four ROBINs will be hosted in about 150 Read-Out Subsystem (ROS) PCs. Event data are forwarded on request via Gigabit Ethernet links and switches to the second-level trigger or to the Event builder. In this paper a discussion of the functionality and real-time properties of the ROS is combined with a presentation of measurement and modelling results for a testbed with a size of about 20% of the final DAQ system. Experimental results on strategies for optimizing the system performance, such as utilization of different network architectures and network transfer protocols, are presented for the testbed, together with extrapolations to the full system.

Keywords

data acquisition; high energy physics instrumentation computing; local area networks; nuclear electronics; peripheral interfaces; position sensitive particle detectors; real-time systems; ATLAS dataflow; LHC; PC; PCI cards; ROBIN; buffers; data-acquisition system; event builder; first-level trigger; gigabit Ethernet links; modeling; network architectures; network transfer protocols; read-out hardware subsystem; real-time property; second-level trigger; subdetector; testbed studies; Data acquisition; Ethernet networks; Hardware; Large Hadron Collider; Personal communication networks; Real time systems; Size measurement; Switches; System performance; System testing; ATLAS; LHC; data acquisition; real-time systems; triggering;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/TNS.2006.873311

Filename

1644963