Since August 1989 the ALEPH detector is collecting data on e+e- collisions provided by the LEP storage ring at CERN. Its main tracking detector, a time projection chamber, has about 50,000 channels, each recording 512 samples of incoming ionization. The ALEPH TPC data acquisition system is based on 768 triple width Fastbus modules, named TPDs, and 36 double width Fastbus modules, named TPPs. The TPC DAQ system performance has been satisfactory since the beginning of LEP physics in 1989, throughout more than two years of operation. The task to coordinate, to reliably operate, to monitor and to maintain several hundreds of complex custom hardware devices has been accomplished. In this paper the performance and the implementation of the TPC DAQ system are presented; furthermore, it is shown how online data processing is used to obtain a substantial reduction of the data volume.
RESULTS IN ONLINE DATA-PROCESSING WITH THE DATA-ACQUISITION SYSTEM OF THE ALEPH-TPC
LUSIANI, Alberto
1993
Abstract
Since August 1989 the ALEPH detector is collecting data on e+e- collisions provided by the LEP storage ring at CERN. Its main tracking detector, a time projection chamber, has about 50,000 channels, each recording 512 samples of incoming ionization. The ALEPH TPC data acquisition system is based on 768 triple width Fastbus modules, named TPDs, and 36 double width Fastbus modules, named TPPs. The TPC DAQ system performance has been satisfactory since the beginning of LEP physics in 1989, throughout more than two years of operation. The task to coordinate, to reliably operate, to monitor and to maintain several hundreds of complex custom hardware devices has been accomplished. In this paper the performance and the implementation of the TPC DAQ system are presented; furthermore, it is shown how online data processing is used to obtain a substantial reduction of the data volume.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
