Grid computing and high energy physics

A relevant part of the High Energy Physics research of the next 15 years will be performed at the CERN LHC collider where about 5000 physicists from 500 institutions spread over the five contents have been working in the last 10 years to the setting up of 4 big experiments. These experiments are scheduled to start data taking in the second half of 2007 and to continue till 2020, accumulating more than 10 Petabytes of data each year. The development of system allowing each physicist to efficiently analyze this amount of data from his/her home institute, is also a major informatics challenge. All the four LHC experiment have made the choice of basing their Computing Models on the recent technologies of Grid Computing and of contributing to the development of these technologies and to the building of a Grid Infrastructure, via the LCG ( LHC Computing Grid Project) and the connected Grid projects (EGEE and others). Using the example of the ATLAS experiment, this paper illustrates the present and future usage of the Grid middleware, hardware and network infrastructure, which in Europe, and in other countries, are developed and maintained by the LCG/EGEE project.