An international group of scientists, which included specialists from the Joint Institute for Nuclear Research, created the EventIndex system. The system deals with data from the ATLAS Experiment at the CERN LHC accelerator. Annually, several billions of particle interactions are detected at this research facility. The EventIndex system not only contains a catalogue of all the registered and simulated events, but also allows scientists to work with the data. The EventIndex project results have been recently published in a high-ranking scientific journal Computing and Software for Big Science.

The work on the EventIndex project is carried out with an active participation of scientists from MLIT JINR under the guidance of Igor Alexandrov. A senior DLNP researcher Fedor Prokoshin heads the JINR project.

General scheme of EventIndex system implemented at end of
LHC Run 2

The EventIndex system is a catalogue of all the events collected, processed, or generated by the ATLAS Experiment at the CERN LHC accelerator and comprises all associated software tools to collect, store, and process this information. Every year of operation, ATLAS records several billions of particle interactions. Those events are processed and analysed. Larger simulated data samples are generated for them. Thus, the data, in fact, becomes even more. The EventIndex catalogue makes it possible to keep track of the location of each event record and be able to search for and retrieve specific events during in-depth analysis. In addition, it allows monitoring integrity and consistency of data collection. Among its functions, there is also a selection of events by trigger solutions and the ability to examine their correlation. Each EventIndex record includes summary information on the event itself and the pointers to the files containing the event data.

Most components of the EventIndex system were created using free and open source software for processing big data. It is worth noting that JINR scientists have made a significant contribution to the development of this system and at present, the obtained experience is being implemented at the NICA Project.