EXPERIMENTAL DATA STORAGE MANAGEMENT IN NEXUS FORMAT AT SYNCHROTRON SOLEIL

At Synchrotron SOLEIL, some 20 beamlines are already in operation and produce daily experimental data files with volumes ranging from a few MB up to 100 GB. Almost all experimental data is stored using the NeXus data format [1]. This logical format, based on an HDF physical format, is suitable for storing any kind of scientific data produced in Neutron or Synchrotron sources. The NeXus format allows experimental data to be recorded together with all needed contextual information about the experiment, instrumentation, sample, user, and so on. Several tools have been developed or are currently under development at SOLEIL, including a web data browser to retrieve, browse and download data, and a command line tool used to export data from NeXus to ASCII or binary data files. The NeXus storage system is fully integrated into the Tango bus [2] through a set of dedicated devices. It is therefore possible to record any data coming from Tango devices into a NeXus file. The storage system is designed to allow recording data from various data sources using a plugin system. In terms of hardware, a high availability system using an innovative cellular storage concept known as Active Circle [3] has been in use since December 2006.