Content & Structure [Top]

Scope and content

The ATLAS detector has been designed to cover the largest possible range of LHC physics: searches for Higgs bosons and alternative schemes for the spontaneous symmetry-breaking mechanism; searches for super-symmetric particles, effects from extra dimensions, new gauge bosons, lepto-quarks, and quark and lepton compositeness indicating extensions to the Standard Model and new physics beyond it; studies of the origin of CP violation via high-precision measurements of CP-violating B-decays; high precision measurements of the third quark family such as the top quark mass and decay properties, rare decays of B-hadrons, spectroscopy of rare B-hadrons, and [Bs0]-mixing.

The ATLAS detector consists of four major components:

• the inner tracker measures the paths of electrically charged particles,
• the calorimeter measures the energies of charged and neutral particles,
• the muon spectrometer measures muon paths to determine their momenta with high precision,
• the magnet system bends charged particles for momentum measurement.

The particle interactions in the ATLAS detector will create an enormous dataflow which will be digested by:

• the trigger system, selecting 100 interesting events per second out of 1000 million others,
• the data acquisition system, channeling the data from the detectors to the storage,
• the computing system, analyzing 1000 million events recorded per year.

ATLAS collaboration

The ATLAS collaboration consists of CERN and a group of institutions from CERN Member and non-Member States that have proposed the ATLAS experiment. The institutions are universities and laboratories (150 in 2004), with about 2000 scientific collaborators from 34 countries. The project is financed by Funding Agencies which are government departments, laboratories or universities connected to or identical with the collaborating institutions. A list of these Funding Agencies can be found in the Memorandum of Understanding mentioned below ("Sources"). The main policy-making powers are the Resource Review Board (RRW), the Plenary Meeting (PM) and the Collaboration Board (CB). The Resource Review Board (RRW) is the body where the ATLAS resources are approved upon proposals from the ATLAS collaboration, and monitored. It is chaired by the CERN Director of Research and composed of representatives of the national funding agencies, the CERN management and the ATLAS management. The Plenary Meeting (PM) is the general forum of the collaboration. All major ATLAS decisions concerning physics objectives and results, hardware and software design, and organizational matters are discussed there. The Collaboration Board (CB) is the policy deciding body. Each institution collaborating in the project is represented in it and has one vote. The Plenary Meeting (PM) and the Collaboration Board (CB) assemble at the ATLAS Weeks, week-long meetings of the ATLAS collaboration, four times a year.

The main executive powers are the ATLAS management, the Executive Board (EB) and the ATLAS Systems. The ATLAS management is composed of the Spokesperson, the Deputy Spokesperson, the Technical Coordinator and the Resource Coordinator. The Spokesperson is the highest level executive of ATLAS, and as such has the overall responsibility of the ATLAS execution. He or she represents the ATLAS executive branch at the Collaboration Board (CB). The Executive Board (EB) is the main body for directing the execution of the ATLAS project and for direct communication between the ATLAS management and the ATLAS Systems. It is composed of the ATLAS management, the System Project leaders, the Magnet Project Leader, Technical coordination staff, the Collaboration Board (CB) Chairperson and Deputy, and up to two additional individuals. The ATLAS Systems (Inner Detector, Magnets, Liquid Argon Calorimeter, Tile Calorimeter, Muon Spectrometer, Shielding, Trigger/ DAQ/ DCS) correspond to performance tasks, major activities involving sets of institutions which will produce hardware and software. Each System includes a Steering Group and an Institute Board. the Steering Group takes decisions on technical execution matters and makes recommendations to the Institute Board. The Institute Board takes decisions on major technical choices and on sharing of resources and responsibilities. Each ATLAS System is chaired by a Project Leader.

The material collected so far was created by Peter Jenni, the ATLAS Spokesperson. It documents the activity of the ATLAS Collaboration in the managerial, scientific and technical areas. For an overview of the topics handled, see section 'System of arrangement'.

* Sources: CERN Annual Report 2003; web-site http://atlas.ch [consulted in May 2004]. 
* Sources: Memorandum of Understanding for Maintenance and Operation of the ATLAS Detector CERN-RRB-2002-035 (28 March 2002); http://atlas.ch [consulted in May 2004]; ATLAS Internal Note GEN-NO-009 (16 September 1994); ATLAS Internal Note GEN-NO-015 (29 November 1996); ATLAS Internal Note GEN-NO-016 (16 December 1996).

Appraisal, destruction and scheduling information

Nothing was destroyed.

Accruals

Further accruals are expected.

System of arrangement

The original order has been preserved. The main categories are as follows: