The NeXus data format

Abstract

NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitions for the exchange of data between applications. NeXus provides structures for raw experimental data as well as for processed data.

A NeXus/HDF5 based file format for STXM

“…Our aim in defining the NXstxm file format has three priorities: 1. have sufficient flexibility to accommodate any scan type 2. the set of common, standard scans should be easy to read and plot 3. encourage saving all beamline and instrument parameters These aims align well with those of NeXus, [23,24] however the variety of scan types produced by STXM instruments makes for some conflict between aims #1 and #2. While it would be possible to define separate application definitions for each of the different scan types listed above, following this strategy for STXM would either be very limiting in the types of defined scans, or produce an unreasonably large number of application definitions.…”

Practices and Standards for Data and Processing at the APS

“…NeXus is a standard for the storage of raw data acquired at neutron and X-ray user beamlines [2,5,6], which is coordinated by a committee representing 14 major facilities. Although it was initially adopted mainly at neutron facilities, X-ray facilities have played an increasing role in its development; e.g., with the project to become fully interoperable with imgCIF (see sites.google.com/site/nexuscbf and [6]) and with the decision of a leading X-ray detector manufacturer, DECTRIS, to use NeXus for their raw data format.…”

IBEX - an EPICS based control system for the ISIS pulsed neutron and muon source

“…a SampleTemp block representing the "SOME:READBACK" IOC device PV. Blocks can have a logging frequency set and values are automatically recorded in the NeXus [15] format data file created at experiment end. A block may also be given a valid range and put under "run control", which means that neutron data collection will automatically be suspended while it is out of range.…”