4.3.1.17. NXentry¶
Status:
base class, extends NXobject
Description:
(required) NXentry describes the measurement.
The top-level NeXus group which contains all the data and associated information that comprise a single measurement. It is mandatory that there is at least one group of this type in the NeXus file.
Symbols:
No symbol table
- Groups cited:
NXcollection, NXdata, NXinstrument, NXmonitor, NXnote, NXparameters, NXprocess, NXsample, NXsubentry, NXuser
Structure:
@default: (optional) NX_CHAR
Declares which NXdata group contains the data to be shown by default. It is used to resolve ambiguity when one NXdata group exists. The value names a child group. If that group itself has a
defaultattribute, continue this chain until an NXdata group is reached.For more information about how NeXus identifies the default plottable data, see the Find Plottable Data, v3 section.
@IDF_Version: (optional) NX_CHAR
ISIS Muon IDF_Version
title: (optional) NX_CHAR
Extended title for entry
experiment_identifier: (optional) NX_CHAR
Unique identifier for the experiment, defined by the facility, possibly linked to the proposals
experiment_description: (optional) NX_CHAR
Brief summary of the experiment, including key objectives.
collection_identifier: (optional) NX_CHAR
User or Data Acquisition defined group of NeXus files or NXentry
collection_description: (optional) NX_CHAR
Brief summary of the collection, including grouping criteria.
entry_identifier: (optional) NX_CHAR
unique identifier for the measurement, defined by the facility.
entry_identifier_uuid: (optional) NX_CHAR
features: (optional) NX_CHAR
Reserved for future use by NIAC.
definition: (optional) NX_CHAR
(alternate use: see same field in NXsubentry for preferred)
Official NeXus NXDL schema to which this entry conforms which must be the name of the NXDL file (case sensitive without the file extension) that the NXDL schema is defined in.
For example the
definitionfield for a file that conformed to the NXarpes.nxdl.xml definition must contain the string NXarpes.This field is provided so that NXentry can be the overlay position in a NeXus data file for an application definition and its set of groups, fields, and attributes.
It is advised to use NXsubentry, instead, as the overlay position.
@version: (optional) NX_CHAR
NXDL version number
@URL: (optional) NX_CHAR
URL of NXDL file
definition_local: (optional) NX_CHAR
DEPRECATED: see same field in NXsubentry for preferred use
Local NXDL schema extended from the entry specified in the
definitionfield. This contains any locally-defined, additional fields in the entry.@version: (optional) NX_CHAR
NXDL version number
@URL: (optional) NX_CHAR
URL of NXDL file
start_time: (optional) NX_DATE_TIME
Starting time of measurement
end_time: (optional) NX_DATE_TIME
Ending time of measurement
duration: (optional) NX_INT {units=NX_TIME}
Duration of measurement
collection_time: (optional) NX_FLOAT {units=NX_TIME}
Time transpired actually collecting data i.e. taking out time when collection was suspended due to e.g. temperature out of range
run_cycle: (optional) NX_CHAR
Such as “2007-3”. Some user facilities organize their beam time into run cycles.
program_name: (optional) NX_CHAR
revision: (optional) NX_CHAR
Revision id of the file due to re-calibration, reprocessing, new analysis, new instrument definition format, …
@comment: (optional) NX_CHAR
pre_sample_flightpath: (optional) NX_FLOAT {units=NX_LENGTH}
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.
DATA: (optional) NXdata
The data group
Note
Before the NIAC2016 meeting [1], at least one NXdata group was required in each NXentry group. At the NIAC2016 meeting, it was decided to make NXdata an optional group in NXentry groups for data files that do not use an application definition. It is recommended strongly that all NeXus data files provide a NXdata group. It is permissable to omit the NXdata group only when defining the default plot is not practical or possible from the available data.
For example, neutron event data may not have anything that makes a useful plot without extensive processing.
Certain application definitions override this decision and require an NXdata group in the NXentry group. The
minOccurs=0attribute in the application definition will indicate the NXdata group is optional, otherwise, it is required.experiment_documentation: (optional) NXnote
Description of the full experiment (document in pdf, latex, …)
notes: (optional) NXnote
Notes describing entry
thumbnail: (optional) NXnote
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.
@type: (optional) NX_CHAR
The mime type should be an
image/*Obligatory value:
image/*USER: (optional) NXuser
SAMPLE: (optional) NXsample
INSTRUMENT: (optional) NXinstrument
COLLECTION: (optional) NXcollection
MONITOR: (optional) NXmonitor
PARAMETERS: (optional) NXparameters
PROCESS: (optional) NXprocess
SUBENTRY: (optional) NXsubentry
Hypertext Anchors¶
List of hypertext anchors for all groups, fields, attributes, and links defined in this class.