Title :
The fast control system for HERA-B
Author :
Fuljahn, T. ; Hochweller, G. ; Ressing, D.
Author_Institution :
DESY, Hamburg, Germany
Abstract :
The HERA-B experiment is dedicated to measure CP-violation in decays of neutral B-mesons. The B-mesons are produced in a nearly overwhelming background of inelastic proton-nucleon-interactions. To reconstruct a sufficient number of B-decays the experiment has to be operated with multiple interactions at a 10 MHz event rate. A granularity of 540,000 channels is required. The challenge for the DAQ system is deadtimeless readout. This requires unprecedented speed of storing and labeling the data. A 50 kHz first level trigger rate needs a fast distribution of accepted-event identifiers. Ambitious plans for drift time measurements require a high precision time reference for the front end electronics. A fast control system has been developed to fulfil these requirements. The system consists of a VME-accessible mother unit with trigger and command processing logic, a two-stage signal distribution system and one individually configurable daughter module with timing adjustment capabilities in each of more than 200 front end electronics crates
Keywords :
client-server systems; computerised control; data acquisition; high energy physics instrumentation computing; HERA-B; accepted-event identifiers; command processing logic; control software; data acquisition system; deadtimeless readout; drift time measurement; fast control system; first level trigger; interfaces; timing adjustment; trigger logic; two-stage signal distribution system; Clocks; Control systems; Detectors; Event detection; Pipelines; Signal processing; Storage rings; Synchronization; Time measurement; Timing;
Conference_Titel :
Nuclear Science Symposium, 1998. Conference Record. 1998 IEEE
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-5021-9
DOI :
10.1109/NSSMIC.1998.775157
