.. index:: plotting Declares which :ref:`NXdata` group contains the data to be shown by default. It is needed to resolve ambiguity when more than one :ref:`NXdata` group exists. The value is the name of the default :ref:`NXdata` group. It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See http://wiki.nexusformat.org/2014_How_to_find_default_data for a summary of the discussion. Group of multiple application definitions for "multi-modal" (e.g. SAXS/WAXS) measurements. ``NXsubentry`` is a base class virtually identical to :ref:`NXentry` and is used as the (overlay) location for application definitions. Use a separate ``NXsubentry`` for each application definition. To use ``NXsubentry`` with a hypothetical application definition called ``NXmyappdef``: * Create a group with attribute ``NX_class="NXsubentry"`` * Within that group, create a field called ``definition="NXmyappdef"``. * There are two optional attributes of definition: ``version`` and ``URL`` The intended use is to define application definitions for a multi-modal (a.k.a. multi-technique) :ref:`NXentry`. Previously, an application definition replaced :ref:`NXentry` with its own definition. With the increasing popularity of instruments combining multiple techniques for data collection (such as SAXS/WAXS instruments), it was recognized the application definitions must be entered in the NeXus data file tree as children of :ref:`NXentry`. ISIS Muon IDF_Version Extended title for entry Unique identifier for the experiment, defined by the facility, possibly linked to the proposals Brief summary of the experiment, including key objectives. Description of the full experiment (document in pdf, latex, ...) User or Data Acquisition defined group of NeXus files or :ref:`NXentry` Brief summary of the collection, including grouping criteria. unique identifier for the measurement, defined by the facility. Official NeXus NXDL schema to which this subentry conforms NXDL version number URL of NXDL file Local NXDL schema extended from the subentry specified in the ``definition`` field. This contains any locally-defined, additional fields in the subentry. NXDL version number URL of NXDL file Starting time of measurement Ending time of measurement Duration of measurement Time transpired actually collecting data i.e. taking out time when collection was suspended due to e.g. temperature out of range Such as "2007-3". Some user facilities organize their beam time into run cycles. Name of program used to generate this file Program version number configuration of the program Revision id of the file due to re-calibration, reprocessing, new analysis, new instrument definition format, ... This is the flightpath before the sample position. This can be determined by a chopper, by the moderator or the source itself. In other words: it the distance to the component which gives the T0 signal to the detector electronics. If another component in the NXinstrument hierarchy provides this information, this should be a link. Notes describing entry A small image that is representative of the entry. An example of this is a 640x480 jpeg image automatically produced by a low resolution plot of the NXdata. The value should be an ``image/*``