The Argo YBJ daq and trigger system

The Argo-YBJ experiment has now reached its final design configuration. The detector system consists of a full coverage array (about 5800 square meters) of resistive plate chambers (RPCs). The required throughput depends on the trigger rate and threshold. The DAQ system must be able to sustain a maximum transfer rate of the order of 15 MB/s and a high peak data flow. Data are read out using a typical front-end acquisition chain built around a custom bus. Specialized electronics have been designed and efficient software has been written to perform this task. Data are sent to the on line farm through a switch exploiting a gigabit ethernet protocol. A solution to transfer data from the YBJ laboratory to the laboratories belonging to the Argo-YBJ collaboration exploiting the GRID middleware has also been implemented. In this paper we describe the daq, the trigger environment and the data mover main characteristics and performances.