The ATLAS Data Acquisition and High-Level Trigger: Concept, Design and Status

The Trigger and Data Acquisition system (TDAQ) of the ATLAS experiment at the CERN Large Hadron Collider is based on a multi-level selection process and a hierarchical acquisition tree. The system, consisting of a combination of custom electronics and commercial products from the computing and telecommunication industry, is required to provide an online selection power of 105 and a total throughput in the range of Terabit/sec. This paper introduces the basic system requirements and concepts, describes the architecture of the system, discusses the basic measurements supporting the validity of the design and reports on the actual status of construction and installation

The final design of the ATLAS Trigger/DAQ Readout-Buffer Input (ROBIN) Device

The ATLAS readout subsystem (ROS) is the main interface between 1600 detector front-end readout links (ROL) and the high level (HLT) trigger farms. Its core device, the readout-buffer input (ROBIN), accepts event data on 3 readout links (ROLs) with a maximum rate of 100 kHz and a bandwidth of up to 160\,MB/s per link. Incoming event data is temporarily buffered and delivered via PCI or Gigabit Ethernet on request. Two devices, a XILINX XC2V2000 FPGA and an IBM PowerPC 440, are present, implementing the ROBIN's functionality. Furthermore one 64 MB SDRAM event data buffer is available per ROL. The device supports the ATLAS baseline implementation, which foresees the PCI bus as the main communication path inside the ROS, as well as an optional data path using Gigabit Ethernet to increase scalability when needed. The paper presents the final design of the ATLAS ROBIN. Measurement results, obtained with a prototype device in PCI bus and Gigabit Ethernet setups, show the usability and approve the design choices