Info
The NeXus International Advisory Committee (NIAC) supervises the development and maintenance of the NeXus common data format for neutron, X-ray, and muon science. NeXus is built on top of HDF5 and defines domain-specific rules for organizing experimental data within HDF5 files, plus a dictionary of standardized field names. NeXus is an international standard developed by scientists representing major facilities in Europe, Asia, Australia, and North America. The format serves both as a container for all beamline data and as application definitions for data exchange between programs.
Why NIAC matters for DiffUSE
NeXus is the dominant data format at many synchrotron and neutron facilities where diffuse scattering data is collected. DiffUSE’s data collection/processing pipeline (Mdx2) and any data standards work will need to reckon with NeXus format conventions. The NIAC governance model (facility-delegate voting, ratification of application definitions) is also a relevant precedent for DiffUSE’s own data governance approach.
Governance Structure
- Constitution: at most one voting representative per major neutron, synchrotron X-ray, or muon facility
- Terms: 3-year renewable, nominated by facility directors, approved by committee
- Meetings: biennial as satellite to NOBUGS conference; working meetings in intervening years
- Voting: simple majority at meetings; 2/3 response required for email votes
- Open process: all debates public; non-members encouraged to participate
- Special Interest Groups: appointed editors for instrument definitions and specialized uses
Executive Officers (2-year terms)
- Chair: oversees deliberations
- Executive Secretary: coordinates meetings/debates (need not be member)
- Technical Manager: oversees NeXus API (need not be member)
- Definition Release Manager: oversees definitions/docs release (need not be member)
Current Members
| Name | Facility | Country | Role |
|---|---|---|---|
| Aaron Brewster | Lawrence Berkeley Laboratory | USA | Chair |
| Sandor Brockhauser | Center for Materials Science Data (HU Berlin) | Germany | Executive Secretary |
| Peter Chang | Diamond Light Source | UK | Documentation Release Manager |
| Benjamin Watts | Swiss Light Source | Switzerland | |
| Herbert Bernstein | CIF | (non-facility) | |
| Thomas Caswell | Brookhaven National Laboratory / NSLS-II | USA | |
| Bjorn Clausen | Los Alamos National Laboratory | USA | |
| Heike Gorzig | Helmholtz Zentrum Berlin | Germany | |
| Pete Jemian | Advanced Photon Source | USA | |
| Raymond Osborn | Argonne National Laboratory | USA | (non-facility) |
| Wout de Nolf | European Synchrotron Radiation Facility | France | |
| Takahiro Matsumoto | SPring-8 | Japan | |
| Balazs Bago | Extreme Light Infrastructure | Czech Republic/Hungary/Romania | |
| Russ Berg | Canadian Light Source | Canada | |
| Majid Ounsy | Synchrotron Soleil | France | |
| Chen Zhang | Oak Ridge National Laboratory (SNS/HFIR) | USA | |
| Fabio Dall’Antonia | European XFEL | Germany | |
| Paul Millar | DESY | Germany | |
| Zdenek Matej | MAX IV | Sweden | |
| Fernan Saiz | ALBA | Spain | |
| Fredrik Bolmsten | ESS | Sweden |
Historical Origins
- June 1994: Mark Konnecke (PSI, Switzerland) proposed netCDF-based format at ISIS
- August 1994: Jon Tischler and Mitch Nelson (ORNL)