The D0 Level-3 Trigger / Data Acquisition System

Paper: 316
Session: B (talk)
Speaker: Cutts, David, Brown University, Providence
Keywords: data acquisition systems, trigger systems

The D0 Level-3 Trigger / Data Acquisition System

Dave Cutts, Jan Hoftun and Gordon Watts
Brown University, Providence RI 02912, USA


Ray Zeller
ZRL, Bristol RI 02809, USA

for the D0 Collaboration

We describe the Level-3 trigger / data acquisition system being built
for the D0 experiment at Fermilab, to be used in the Tevatron's high
luminosity Run 2. We focus on the principal changes to the existing
high level trigger at D0, which will build on the existing 384 MByte/s
datapaths from the front-end VME crates to custom multiport memories
(MPMs) associated with commercial processing nodes. The upgrade
replaces the readout components used in Run 1 to transfer data between
the digitizer crates and the MPMs. These new custom components use a
Fibre Channel based interface for transmission but operate with a
simple protocol that provides an inexpensive solution to parallelizing
the data flow, allowing multiple blocks associated with multiple
events to flow, at the same time, from the digitizing crates to the
processor memories. The design is highly scaleable, though the
installation at D0 will need to supply for Run 2 only about
1.5 GBytes/s in bandwidth to the processor farm. We present details
of the design and report on progress in its implementation.