Instruments

The NeXus Design page lists the group classes from which a NeXus file is constructed. They provide the glossary of items that could, in principle, be stored in a standard-conforming NeXus file (other items may be inserted into the file if the author wishes, but they won’t be part of the standard). If you are going to include a particular piece of metadata, consult the [class definitions] (Design.html “wikilink”) to find out what to call it. However, to assist those writing data analysis software, it is useful to provide more than a glossary; it is important to define the required contents of NeXus files that contain data from particular classes of neutron, x-ray, or muon instrument.

As part of the NeXus standard, we have identified a number of generic instruments that describe an appreciable number of existing instruments around the world. Although not identical in every detail, they share enough common characteristics, and more importantly, they require sufficiently similar modes of data analysis, to make a standard description useful. They are in the process of being defined for the NeXus standard. The definitions will be in XML using the NXDL (NeXus Definition Language) format.

Instrument Definitions List

TRAC

[Pete] (Pete_Jemian.html “wikilink”) 15:49, 14 December 2009 (UTC): NeXus definitions TRAC ticket #3 was created to describe the items on this page. Classes that were not already described in NXDL have TRAC tickets created. The status of each of these classes is described in the comments on that page. All new propositions for classes should be described with a new TRAC ticket.

Ratified

These have been voted on by the NIAC and so are official NeXus definitions

• NXTOFRaw: Time-of-Flight Raw Data Editors: [Freddie Akeroyd] (Freddie_Akeroyd.html “wikilink”), [Peter Peterson] (Peter_Peterson.html “wikilink”)

• Monochromatic Neutron and X-ray Powder Diffraction Editor: [Mark Könnecke] (Mark_Koennecke.html “wikilink”), PSI

• Generic Scanning Instrument Editor: [Mark Könnecke] (Mark_Koennecke.html “wikilink”), PSI

• [Monochromatic Neutron and X-ray Triple-Axis Spectrometer] (Monochromatic_Neutron_and_X-ray_Triple-Axis_Spectrometer.html “wikilink”) Editor: [Nicholas Maliszewskyj] (Nickm.html “wikilink”) (NIST Center for Neutron Research, USA).

Proposed

In this case the need for a particular definition has been identified, an editor has been assigned and some detailed discussions have taken place; however the definition has not yet been voted on by the NIAC and so could still undergo modification.

• Monochromatic Neutron and X-ray Single Crystal Diffractometer Editor: [Mark Könnecke] (Mark_Koennecke.html “wikilink”), PSI

• Archive Definition Editor: [Laurent Lerusse] (L.lerusse.html “wikilink”) (CCLRC - Rutherford Appleton Laboratory, e-Science, UK)

• Monochromatic Neutron and X-ray Small Angle Scattering Editor: Ron Ghosh (Institut Laue Langevin, France).

• [Processed Data] (Processed_Data.html “wikilink”) Editor: [Ray Osborn] (Ray_Osborn.html “wikilink”) (Argonne National Laboratory, USA)

• X-Ray Synchrotron Raw Editor: [Stuart Campbell] (Stuart_Campbell.html “wikilink”) (Diamond Light Source, UK)

• Muon Time Differential Editor: [Steve Cottrell] (Steve_Cottrell.html “wikilink”) (ISIS, UK)

Planned

These definitions are currently being worked on and so could still undergo major revisions. When they near completion they will be moved into the Proposed category above.

• Diffraction

  • Protein Crystallography

  • Time-of-Flight Neutron Powder Diffraction, Editor: [Peter Peterson] (Pfpeterson.html “wikilink”) (Spallation Neutron Source, USA).

  • [Time-of-Flight Neutron Single Crystal Diffractometer] (Time-of-Flight_Neutron_Single_Crystal_Diffractometer.html “wikilink”), Editor: TBA

• Reflectometry

  • [Time-of-Flight Neutron Reflectometry] (Time-of-Flight_Neutron_Reflectometry.html “wikilink”), Editor: Robert Dalgliesh (ISIS Pulsed Neutron and Muon Source, UK)

  • Monochromatic Neutron and X-ray Reflectometry, Editor: Paul Kienzle (NIST Center for Neutron Research, USA)

• Imaging

  • X-ray Tomography

• Small-Angle Scattering

  • Grazing Incidence Small-Angle X-ray Scattering, Editor: TBA

  • [Time-of-Flight Small Angle Scattering] (Time-of-Flight_Small_Angle_Scattering.html “wikilink”), Editor: Stephen King (ISIS Pulsed Neutron and Muon Source, UK)

  • Ultra-Small-Angle Neutron Scattering, Editor: TBA

  • Ultra-Small-Angle X-ray Scattering, Editor: [User%3APete Jemian] (Pete_Jemian.html “wikilink”) (Advanced Photon Source, USA)

• Spectrometers

  • [Time-of-Flight Neutron Direct Geometry Spectrometer] (Time-of-Flight_Neutron_Direct_Geometry_Spectrometer.html “wikilink”), Editor: Toby Perring (ISIS Pulsed Neutron and Muon Source, UK)

  • [Time-of-Flight Neutron Indirect Geometry Spectrometer] (Time-of-Flight_Neutron_Indirect_Geometry_Spectrometer.html “wikilink”), Editor: Martyn Bull (ISIS Pulsed Neutron and Muon Source, UK)

  • XAS: X-ray Absorption Spectroscopy

  • XPCS: X-ray Photon Correlation Spectroscopy

• Spin-Echo

  • [Neutron Spin Echo] (Neutron_Spin_Echo.html “wikilink”), Editor: Robert Georgii (FRM-II, Germany)

  • [Time-of-Flight Neutron Spin Echo] (Time-of-Flight_Neutron_Spin_Echo.html “wikilink”), Editor: TBA