.. auto-generated by script ../../../../utils/nxdl2rst.py from the NXDL source NXgrating.nxdl.xml

.. index::
    ! NXgrating (base class)
    ! grating (base class)
    see: grating (base class); NXgrating

.. _NXgrating:

=========
NXgrating
=========

**Status**:

  base class, extends :ref:`NXobject`

**Description**:

  A diffraction grating, as could be used in a soft X-ray monochromator

**Symbols**:

  No symbol table

**Groups cited**:
  :ref:`NXdata`, :ref:`NXshape`, :ref:`NXtransformations`

.. index:: NXshape (base class); used in base class, NXdata (base class); used in base class, NXtransformations (base class); used in base class

**Structure**:

  .. _/NXgrating@default-attribute:

  .. index:: default (file attribute)

  **@default**: (optional) :ref:`NX_CHAR <NX_CHAR>`

    .. index:: plotting

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

  .. _/NXgrating/angles-field:

  .. index:: angles (field)

  **angles[2]**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_ANGLE <NX_ANGLE>`}

    Blaze or trapezoidal angles, with the angle of the upstream facing edge listed first. Blazed gratings can be identified by the low value of the first-listed angle.

  .. _/NXgrating/period-field:

  .. index:: period (field)

  **period[]**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}

    List of polynomial coefficients describing the spatial separation of lines/grooves as a function of position along the grating, in increasing powers of position. Gratings which do not have variable line spacing will only have a single coefficient (constant).

  .. _/NXgrating/duty_cycle-field:

  .. index:: duty_cycle (field)

  **duty_cycle**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}


  .. _/NXgrating/depth-field:

  .. index:: depth (field)

  **depth**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}


  .. _/NXgrating/diffraction_order-field:

  .. index:: diffraction_order (field)

  **diffraction_order**: (optional) :ref:`NX_INT <NX_INT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}


  .. _/NXgrating/deflection_angle-field:

  .. index:: deflection_angle (field)

  **deflection_angle**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_ANGLE <NX_ANGLE>`}

    Angle between the incident beam and the utilised outgoing beam.

  .. _/NXgrating/interior_atmosphere-field:

  .. index:: interior_atmosphere (field)

  **interior_atmosphere**: (optional) :ref:`NX_CHAR <NX_CHAR>`


    Any of these values: ``vacuum`` | ``helium`` | ``argon``

  .. _/NXgrating/substrate_material-field:

  .. index:: substrate_material (field)

  **substrate_material**: (optional) :ref:`NX_CHAR <NX_CHAR>`


  .. _/NXgrating/substrate_density-field:

  .. index:: substrate_density (field)

  **substrate_density**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_MASS_DENSITY <NX_MASS_DENSITY>`}


  .. _/NXgrating/substrate_thickness-field:

  .. index:: substrate_thickness (field)

  **substrate_thickness**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}


  .. _/NXgrating/coating_material-field:

  .. index:: coating_material (field)

  **coating_material**: (optional) :ref:`NX_CHAR <NX_CHAR>`


  .. _/NXgrating/substrate_roughness-field:

  .. index:: substrate_roughness (field)

  **substrate_roughness**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}


  .. _/NXgrating/coating_roughness-field:

  .. index:: coating_roughness (field)

  **coating_roughness**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}


  .. _/NXgrating/layer_thickness-field:

  .. index:: layer_thickness (field)

  **layer_thickness**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}

    An array describing the thickness of each layer

  .. _/NXgrating/shape-group:

  **shape**: (optional) :ref:`NXshape`

    A NXshape group describing the shape of the mirror

  .. _/NXgrating/figure_data-group:

  **figure_data**: (optional) :ref:`NXdata`

    Numerical description of the surface figure of the mirror.

  .. _/NXgrating/TRANSFORMATIONS-group:

  **TRANSFORMATIONS**: (optional) :ref:`NXtransformations`

    "Engineering" position of the grating


Hypertext Anchors
-----------------

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


================================================================================== ==================================================================================
documentation (reST source) anchor                                                 web page (HTML) anchor                                                            
================================================================================== ==================================================================================
:ref:`/NXgrating/angles-field </NXgrating/angles-field>`                           :ref:`#nxgrating-angles-field </NXgrating/angles-field>`                          
:ref:`/NXgrating/coating_material-field </NXgrating/coating_material-field>`       :ref:`#nxgrating-coating-material-field </NXgrating/coating_material-field>`      
:ref:`/NXgrating/coating_roughness-field </NXgrating/coating_roughness-field>`     :ref:`#nxgrating-coating-roughness-field </NXgrating/coating_roughness-field>`    
:ref:`/NXgrating/deflection_angle-field </NXgrating/deflection_angle-field>`       :ref:`#nxgrating-deflection-angle-field </NXgrating/deflection_angle-field>`      
:ref:`/NXgrating/depth-field </NXgrating/depth-field>`                             :ref:`#nxgrating-depth-field </NXgrating/depth-field>`                            
:ref:`/NXgrating/diffraction_order-field </NXgrating/diffraction_order-field>`     :ref:`#nxgrating-diffraction-order-field </NXgrating/diffraction_order-field>`    
:ref:`/NXgrating/duty_cycle-field </NXgrating/duty_cycle-field>`                   :ref:`#nxgrating-duty-cycle-field </NXgrating/duty_cycle-field>`                  
:ref:`/NXgrating/figure_data-group </NXgrating/figure_data-group>`                 :ref:`#nxgrating-figure-data-group </NXgrating/figure_data-group>`                
:ref:`/NXgrating/interior_atmosphere-field </NXgrating/interior_atmosphere-field>` :ref:`#nxgrating-interior-atmosphere-field </NXgrating/interior_atmosphere-field>`
:ref:`/NXgrating/layer_thickness-field </NXgrating/layer_thickness-field>`         :ref:`#nxgrating-layer-thickness-field </NXgrating/layer_thickness-field>`        
:ref:`/NXgrating/period-field </NXgrating/period-field>`                           :ref:`#nxgrating-period-field </NXgrating/period-field>`                          
:ref:`/NXgrating/shape-group </NXgrating/shape-group>`                             :ref:`#nxgrating-shape-group </NXgrating/shape-group>`                            
:ref:`/NXgrating/substrate_density-field </NXgrating/substrate_density-field>`     :ref:`#nxgrating-substrate-density-field </NXgrating/substrate_density-field>`    
:ref:`/NXgrating/substrate_material-field </NXgrating/substrate_material-field>`   :ref:`#nxgrating-substrate-material-field </NXgrating/substrate_material-field>`  
:ref:`/NXgrating/substrate_roughness-field </NXgrating/substrate_roughness-field>` :ref:`#nxgrating-substrate-roughness-field </NXgrating/substrate_roughness-field>`
:ref:`/NXgrating/substrate_thickness-field </NXgrating/substrate_thickness-field>` :ref:`#nxgrating-substrate-thickness-field </NXgrating/substrate_thickness-field>`
:ref:`/NXgrating/TRANSFORMATIONS-group </NXgrating/TRANSFORMATIONS-group>`         :ref:`#nxgrating-transformations-group </NXgrating/TRANSFORMATIONS-group>`        
:ref:`/NXgrating@default-attribute </NXgrating@default-attribute>`                 :ref:`#nxgrating-default-attribute </NXgrating@default-attribute>`                
================================================================================== ==================================================================================


**NXDL Source**:
  https://github.com/FAIRmat-Experimental/nexus_definitions/tree/fairmat/base_classes/NXgrating.nxdl.xml