Apr 1, 2000
BELLE DAQ System - Status and Future
- Institute of Particle and Nuclear Studies, KEK
- Computing Research Center, KEK
- Department of Physics, University of Tokyo
- Department of Physics, Osaka University
The BELLE experiment started taking data from June 1999
for the study of the CP violation in B meson decays.
The DAQ system for BELLE was designed so
that it could handle the trigger rate up to 500Hz with the event size of
30KB. The system consists of the unified readout system based on the
Q-to-T conversion, the event builder, the online computer farm
and the data transfer system to a mass storage.
It is now operated at the average trigger rate of 200Hz without
any serious problem.
The performance of the system under this condition is reported.
In particular, the data processing in the down stream of the DAQ system
is discussed in detail, which includes the L3 trigger and the data monitoring
scheme. In the latter part of the talk,
a future upgrade plan of the DAQ system is described. The plan is
to replace the current event builder, the online computer farm and
the data transfer system with a bunch of PC servers connected with
100base-T network. The R&D status on the upgrade is reported.