General Tree Structure

The general tree structure (with parts described in the sections below) will follow this outline:

HDF5 address	structure	reference
/	(NXroot)	SPEC Data File
/@default	NX_CHAR	SPEC Data File
/@SPEC_num_headers	NX_INT	SPEC Data File
/SCAN	NXentry	Scan
/SCAN/@default	NX_CHAR	Scan
/SCAN/command	NX_CHAR	Scan
/SCAN/comments	NX_CHAR	Scan
/SCAN/counter_cross_reference	NXnote	Counters
/SCAN/counting_basis	NX_CHAR	Scan
/SCAN/data	NXdata	Scan Data
/SCAN/data/@axes	NX_CHAR	Scan Data
/SCAN/data/@signal	NX_CHAR	Scan Data
/SCAN/data/{AXIS}	NX_NUMBER	Scan Data
/SCAN/data/{COLUMN}	NX_NUMBER	Scan Data
/SCAN/data/{SIGNAL}	NX_NUMBER	Scan Data
/SCAN/date	NX_DATE_TIME	Scan
/SCAN/DEGC_SP	NX_NUMBER	Scan
/SCAN/experiment_description	NX_CHAR	Scan
/SCAN/G	NXnote	Geometry
/SCAN/G/G0	NX_NUMBER[]	Geometry
/SCAN/G/G1	NX_NUMBER[]	Geometry
/SCAN/G/G3	NX_NUMBER[]	Geometry
/SCAN/G/G4	NX_NUMBER[]	Geometry
/SCAN/instrument	NXinstrument	Instrument
/SCAN/instrument/diffractometer	NXnote	Geometry
/SCAN/instrument/geometry_parameters	NXnote	link to /SCAN/instrument/diffractometer
/SCAN/instrument/name	NX_CHAR	Geometry
/SCAN/instrument/monochromator	NXmonochromator	Geometry
/SCAN/instrument/monochromator/wavelength	NX_NUMBER	Geometry
/SCAN/instrument/positioners	NXnote	Positioners
/SCAN/M	NX_NUMBER	Scan
/SCAN/MCA	NXnote	Multi-channel analyzer
/SCAN/metadata	NXnote	UNICAT-style metadata
/SCAN/monitor	NXmonitor	Scan
/SCAN/monitor/preset	NX_NUMBER	Scan
/SCAN/positioner_cross_reference	NXnote	Positioners
/SCAN/positioners	NXnote	Positioners
/SCAN/positioners/{POSITIONER}	NXpositioner	Positioners
/SCAN/Q	NX_NUMBER[3]	Geometry
/SCAN/sample	NXsample	Sample
/SCAN/sample/diffractometer_mode	NX_CHAR	Geometry
/SCAN/sample/diffractometer_sector	NX_NUMBER	Geometry
/SCAN/sample/ub_matrix	NX_NUMBER[3,3]	Geometry
/SCAN/sample/unit_cell_a	NX_NUMBER	only twoc geometry
/SCAN/sample/unit_cell_abc	NX_NUMBER[3]	Geometry
/SCAN/sample/unit_cell_alphabetagamma	NX_NUMBER[3]	Geometry
/SCAN/sample/unit_cell_b	NX_NUMBER	only twoc geometry
/SCAN/sample/unit_cell_gamma	NX_NUMBER	only twoc geometry
/SCAN/sample/unit_cell	NX_NUMBER[6]	Geometry
/SCAN/sample/beam	NXbeam	Geometry
/SCAN/sample/beam/incident_wavelength	NX_NUMBER	Geometry
/SCAN/sample/or0	NXnote	Geometry
/SCAN/sample/or0/{ANGLE}	NX_NUMBER	Geometry
/SCAN/sample/or0/{HKL}	NX_NUMBER	Geometry
/SCAN/sample/or0/wavelength	NX_NUMBER	Geometry
/SCAN/sample/or1	NXnote	Geometry
/SCAN/sample/or1/{ANGLE}	NX_NUMBER	Geometry
/SCAN/sample/or1/{HKL}	NX_NUMBER	Geometry
/SCAN/sample/or1/wavelength	NX_NUMBER	Geometry
/SCAN/sample/temperature	NXlog	Temperature
/SCAN/scan_number	NX_INT	Scan
/SCAN/T	NX_NUMBER	Scan
/SCAN/TEMP_SP	NX_NUMBER	Scan
/SCAN/title	NX_CHAR	Scan
/SCAN/{UNRECOGNIZED}	NXnote	Unrecognized Control Line
/SCAN/UserReserved	NXnote	SPEC UserReserved
/SCAN/UXML	NXnote	UXML

NeXus base classes

These classes are used by spec2nexus to structure a NeXus HDF5 data file.

NeXus base class	documentation URL
NXbeam	https://manual.nexusformat.org/classes/base_classes/NXbeam.html
NXdata	https://manual.nexusformat.org/classes/base_classes/NXdata.html
NXdetector	https://manual.nexusformat.org/classes/base_classes/NXdetector.html
NXentry	https://manual.nexusformat.org/classes/base_classes/NXentry.html
NXinstrument	https://manual.nexusformat.org/classes/base_classes/NXinstrument.html
NXmonitor	https://manual.nexusformat.org/classes/base_classes/NXmonitor.html
NXmonochromator	https://manual.nexusformat.org/classes/base_classes/NXmonochromator.html
NXnote	https://manual.nexusformat.org/classes/base_classes/NXnote.html
NXpositioner	https://manual.nexusformat.org/classes/base_classes/NXpositioner.html
NXroot	https://manual.nexusformat.org/classes/base_classes/NXroot.html
NXsample	https://manual.nexusformat.org/classes/base_classes/NXsample.html

Visit the NeXus documentation for a complete list of NeXus classes: https://manual.nexusformat.org/classes/index.html

NeXus data types

These data types are used by spec2nexus to structure a NeXus HDF5 data file.

type	description
NX_CHAR	string representation (UTF-8)
NX_DATE_TIME	ISO8601 date/time representation
NX_INT	any representation of an integer number
NX_NUMBER	any valid NeXus number representation (scaler or array)

Visit the NeXus documentation for a complete list of NeXus data types (and unit categories): https://manual.nexusformat.org/nxdl-types.html