Performance of the L3 second level trigger implemented for the LEP II with the SGS Thomson C104 packet switch

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · IEEE Transactions on Nuclear Science

DOI:https://doi.org/10.1109/23.710933· OSTI ID:665237

Blaising, J J; Chollet-Le Flour, F ^[1]; Cai, X ^[2]

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1. LAPP/IN2P3, Annecy-le-Vieux (France)
2. MIT, Cambridge, MA (United States). L.N.S.; and others

The L3 experiment is one of the four experiments collecting data at LEP. For the LEP phase 2, the second level trigger has been upgraded to a network of 28 ST T9000 transputers and 2 ST C104 asynchronous packet switches interconnected by IEEE1355 links. It collects trigger data at each LEP crossing (22 {micro}s), builds-up the trigger data block, processes it and rejects online the background events in a few milliseconds. The L3 data acquisition has been running with this system since July 1995. In the data-taking environment and for different hardware and software implementations, the event building throughput rate has been measured. A bandwidth of 5.9 Mbytes per second per link has been measured in a configuration with 12 sources and one processing unit connected with 2 links. The expected global throughput of 70 Mbytes per second has been measured in a farm of 6 processing units. While varying the number of sources and destinations, the authors didn`t observe any significant bandwidth loss. Nevertheless performance relies strongly on some software implementation choices, which are presented and discussed.

• OSTI ID: 665237
• Report Number(s): CONF-9709140--
• Journal Information: IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 4Pt1 Vol. 45; ISSN 0018-9499; ISSN IETNAE
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
DATA ACQUISITION SYSTEMS
LEP STORAGE RINGS
PERFORMANCE
RADIATION DETECTORS
TRIGGER CIRCUITS