1. Results of NIAC Meeting April 26-28 P.F. Peterson Executive Secretary, NIAC

2. What is NeXus? Neutron e X-ray μ (muon) science data format

3. Is it based on anything? Hierarchical Data Format (4 and 5) –NXopen(filename,NXACC_CREATE4,handle) –NXopen(filename,NXACC_CREATE5,handle) eXtensible Markup Language (in 3.0) –NXopen(filename,NXACC_CREATEX,handle) –NXopen(filename,NXACC_RDWR,handle) –NXopen(filename,NXACC_READ,handle)

4. What is the NIAC? NeXus International Advisory Committee “… supervise the development and maintenance of the NeXus common data format for neutron, x-ray, and muon science.” Formed in October of 2003

5. NIAC Members Freddie Akeroyd, ISIS RAL Stuart Campbell, DIAMOND RAL Stephen Cotrell, ISIS RAL Matthias Drochner, DIDO (FRJ-2) FZ-Juelich Ron Ghosh, ILL Andy Gotz, ESRF Nick Hauser, BI ANSTO Przemek Klosowski, NCNR NIST Mark Koennecke, PSI Peter Link, FRM2 TUM Nick Maliszewskyj, NCNR NIST (technical chair) Ray Osborn, IPNS ANL (chair) Toshiya Otomo, KENS and J-PARC KEK Peter Peterson, SNS ORNL (executive secretary) Thomas Proffen, MLNSC LANL

6. What do instrument definitions do? NXdata contain information for “simple plotting” Instrument definitions declare information required for data reduction/analysis Information useful for data treatment, but not required, is also denoted

7. NIAC Meeting Results Minutes NeXus API (NAPI) user reference guide NAPI 3.0 beta released May 20 Release and testing plan Technical reference manual Example files

8. Technical Reference Manual Overview of definitions Explanation of definition format Base classes Instrument definitions

9. Instrument Definitions Cartoon of prototype instrument Description of instrument in simple terms Overview of definition contents Definition in metaDTD format

10. Instrument Definitions Monochromatic Reflectometry Small Angle Scattering Time of Flight Direct Geometry Spectrometer Time of Flight Powder Diffraction Time of Flight Reflectometry Triple Axis Spectrometer Muon Instruments

11. Instrument Definitions The instrument definitions will be submitted to the instrument editors for comments and finalization. A complete proposal including examples should be ready by May 20. The initial release of these definitions will be ratified by a vote on May 27 by the NIAC.