The Argo YBJ daq system and the GRID based data transfer

The Argo-YBJ experiment has now reached itsfinal design configuration. The detector system consists of a fullcoverage array (about 5800 square meters) of Resistive PlateChambers (RPCs). The throughput depends on the trigger rateand threshold. The DAQ system must be able to sustain a max-imum transfer rate of the order of 15 MB/s and a high peakdata flow. Data are read out using a typical front-end acquisitionchain built around a custom bus. Specialized electronics have beendesigned and dedicated software has been written to perform thistask. Data are sent to the online farm through a switch exploitinga gigabit ethernet protocol. A solution to transfer data from theYBJ laboratory to the laboratories belonging to the Argo-YBJcollaboration exploiting the GRID middleware has also beenimplemented. In this paper we describe the daq and the datamover main characteristics and performance.