ATLAS High-Level Trigger, Data Acquisition and Controls Technical Design Report

• This Technical Design Report (TDR) for the High-level Trigger (HLT), Data Acquisition (DAQ) and Controls of the ATLAS experiment builds on the earlier documents published on these systems: Trigger Performance Status Report, DAQ, EF, LVL2 and DCS Technical Progress Report, and High-Level Triggers, DAQ and DCS Technical Proposal. Much background and preparatory work relevant to this TDR is referenced in the above documents. In addition, a large amount of detailed technical documentation has been produced in support of this TDR. These documents are referenced in the appropriate places in the following chapters. This section introduces the overall organization of the document. The following sections give an overview of the principal system requirements and functions, as well as a brief description of the principal data types used in the Trigger/DAQ (TDAQ) system. The document has been organized into four parts: Part I — Global View Chapters 2, 3 and 4 address the principal system and experiment parameters which define the main requirements of the HLT, DAQ and Controls system. The global system operations, and the physics requirements and event selection strategy are also addressed. Chapter 5 defines the overall architecture of the system and analyses the requirements of its principal components, while Chapters 6 and 7 address more specific fault-tolerance and monitoring issues. Part II — System Components This part describes in more detail the principal components and functions of the system. Chapter 8 addresses the final prototype design and performance of the Data Flow component. These are responsible for the transport of event data from the output of the detector Read Out Links (ROLs) via the HLT system (where event selection takes place) to mass storage. Chapter 9 explains the decomposition of the HLT into a second level trigger (LVL2) and an Event Filter (EF). It details the design of the data flow within the HLT, the specifics of the HLT system supervision, and the design and implementation of the Event Selection Software (ESS). Chapter 10 addresses the Online Software which is responsible for the run control and DAQ supervision of the entire TDAQ and detector systems during data taking. It is also responsible for miscellaneous services such as error reporting, run parameter accessibility, and histogramming and monitoring support. Chapter 11 describes the Detector Control System (DCS), responsible for the control and supervision of all the detector hardware and of the services and the infrastructure of the experiment. The DCS is also the interface point for information exchange between ATLAS and the LHC accelerator. Chapter 12 draws together the various aspects of experiment control detailed in previous chapters and examines several use-cases for the overall operation and control of the experiment, including: data-taking operations, calibration runs, and operations required outside data-taking. Part III — System Performance Chapter 13 addresses the physics selection. The tools used for physics selection are described along with the event-selection algorithms and their performance. Overall HLT output rates and sizes are also discussed. An initial analysis of how ATLAS will handle the first year of running from the point of view of TDAQ is presented. Chapter 14 discusses the overall performance of the HLT/DAQ system from various points of view, namely the HLT performance as evaluated in dedicated testbeds, the overall performance of the TDAQ system in a testbed of ~10% ATLAS size, and functional tests of the system in the detector test beam environment. Data from these various testbeds are also used to calibrate a detailed discrete-event -simulation model of data flow in the full-scale system. Part IV — Organization and Planning Chapter 15 discusses quality-assurance issues and explains the software-development process employed. Chapter 16 presents the system costing and staging scenario. Chapter 17 presents the overall organization of the project and general system-resource issues. Chapter 18 presents the short-term HLT/DAQ work-plan for the next phase of the project as well as the global development schedule up to LHC turn-on in 2007.

Subject headings

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Keyword

ATLAS Trigger Data Acquisition Controls LHC

Publication and Content Type

rap (subject category)

vet (subject category)