The UA1 VME based data readout and multiprocessor system

The UA1 experiment is a large multi-purpose particle physics detector system. It was designed to produce full solid-angle coverage around the LSS5 intersection region of the CERN proton-antiproton collider operating at a centre of mass of 540 Gev. The experiment has been operational since November 1981 and the next data-taking period is scheduled for September 1984. At present an upgrade program involving the installation of new detectors and the improvements of the data acquisition system is in progress. This paper describes the current upgrade of the data readout and online data handling facilities by means of a multicrate and multiprocessor system based on the industrial standard VME/VMX bus and the M68000 microprocessor family.