2.3.3.1.33. NXmonochromator

Status:

base class, extends NXobject

Description:

A wavelength defining device. ...

A wavelength defining device.

This is a base class for everything which selects a wavelength or energy, be it a monochromator crystal, a velocity selector, an undulator or whatever.

The expected units are:

  • wavelength: angstrom

  • energy: eV

Symbols:

No symbol table

Groups cited:

NXaperture, NXcrystal, NXdata, NXgeometry, NXgrating, NXoff_geometry, NXtransformations, NXvelocity_selector

Structure:

@default: (optional) NX_CHAR

Declares which child group contains a path leading ...

Declares which child group contains a path leading to a 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 https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion.

wavelength: (optional) NX_FLOAT {units=NX_WAVELENGTH}

wavelength selected

wavelength_error: (optional) NX_FLOAT {units=NX_WAVELENGTH}

DEPRECATED: see https://github.com/nexusformat/definitions/issues/820

wavelength standard deviation

wavelength_errors: (optional) NX_FLOAT {units=NX_WAVELENGTH}

wavelength standard deviation

energy: (optional) NX_FLOAT {units=NX_ENERGY}

energy selected

energy_error: (optional) NX_FLOAT {units=NX_ENERGY}

DEPRECATED: see https://github.com/nexusformat/definitions/issues/820

energy standard deviation

energy_errors: (optional) NX_FLOAT {units=NX_ENERGY}

energy standard deviation

energy_dispersion: (optional) NX_FLOAT {units=NX_ANY}

Energy dispersion at the exit slit, typically given as eV/mm.

wavelength_dispersion: (optional) NX_FLOAT {units=NX_ANY}

Wavelength dispersion at the exit slit.

depends_on: (optional) NX_CHAR

NeXus positions components by applying a set of translations and rotations ...

NeXus positions components by applying a set of translations and rotations to apply to the component starting from 0, 0, 0. The order of these operations is critical and forms what NeXus calls a dependency chain. The depends_on field defines the path to the top most operation of the dependency chain or the string “.” if located in the origin. Usually these operations are stored in a NXtransformations group. But NeXus allows them to be stored anywhere.

entrance_slit: (optional) NXaperture

Size, position and shape of the entrance slit of the monochromator.

exit_slit: (optional) NXaperture

Size, position and shape of the exit slit of the monochromator.

distribution: (optional) NXdata

geometry: (optional) NXgeometry

DEPRECATED: Use the field depends_on and NXtransformations to position the monochromator and NXoff_geometry to describe its shape instead

OFF_GEOMETRY: (optional) NXoff_geometry

This group describes the shape of the beam line component

CRYSTAL: (optional) NXcrystal

Use as many crystals as necessary to describe

VELOCITY_SELECTOR: (optional) NXvelocity_selector

GRATING: (optional) NXgrating

For diffraction grating based monochromators

TRANSFORMATIONS: (optional) NXtransformations

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/base_classes/NXmonochromator.nxdl.xml