Nexus — Proposal for a HDF-Based Data Exchange Standard for the Neutron Scattering Community

The need to convert neutron scattering data from site specific data formats to a format understood by data analysis programs has exercised the users of neutron scattering facilities since the invention of neutron scattering and computers. Recent developments in computing, neutron scattering technology and politics have made this problem big enough to justify a proposal for a data exchange format (DEF) for neutron scattering. The proposed data standard is organized in four levels: The first is the physical file format, which will be the Hierarchical Data Format (HDF) [1] developed by the National Center for Super Computer Applications (NCSA). The second level gives guidelines for storing individual data items in the file. A common name convention and a common structure for an exchange file will significantly facilitate the implementation and reuse of software. Therefore the third level defines a recommended structure for arranging and classifying information in the file in a logical manner. The fourth level is a set of naming conventions and a glossary of names for neutron scattering related data items. The standard is extensible. Data items can be added to the file without interfering with the standard. The standard is suggested for voluntary adoption by the neutron scattering community. The authors invite comments from all interested parties.