.. auto-generated by dev_tools.docs.nxdl from the NXDL source base_classes/NXvelocity_selector.nxdl.xml -- DO NOT EDIT

.. index::
    ! NXvelocity_selector (base class)
    ! velocity_selector (base class)
    see: velocity_selector (base class); NXvelocity_selector

.. _NXvelocity_selector:

===================
NXvelocity_selector
===================

**Status**:

  base class, extends :ref:`NXcomponent`

**Description**:

  A neutron velocity selector

**Symbols**:

  No symbol table

**Groups cited**:
  :ref:`NXgeometry`, :ref:`NXoff_geometry`

.. index:: NXgeometry (base class); used in base class, NXoff_geometry (base class); used in base class

**Structure**:

  .. _/NXvelocity_selector/type-field:

  .. index:: type (field)

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

    velocity selector type

  .. _/NXvelocity_selector/rotation_speed-field:

  .. index:: rotation_speed (field)

  **rotation_speed**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_FREQUENCY <NX_FREQUENCY>`} 

    velocity selector rotation speed

  .. _/NXvelocity_selector/radius-field:

  .. index:: radius (field)

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

    radius at beam centre

  .. _/NXvelocity_selector/spwidth-field:

  .. index:: spwidth (field)

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

    spoke width at beam centre

  .. _/NXvelocity_selector/length-field:

  .. index:: length (field)

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

    rotor length

  .. _/NXvelocity_selector/num-field:

  .. index:: num (field)

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

    number of spokes/lamella

  .. _/NXvelocity_selector/twist-field:

  .. index:: twist (field)

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

    twist angle along axis

  .. _/NXvelocity_selector/table-field:

  .. index:: table (field)

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

    offset vertical angle

  .. _/NXvelocity_selector/height-field:

  .. index:: height (field)

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

    input beam height

  .. _/NXvelocity_selector/width-field:

  .. index:: width (field)

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

    input beam width

  .. _/NXvelocity_selector/wavelength-field:

  .. index:: wavelength (field)

  **wavelength**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_WAVELENGTH <NX_WAVELENGTH>`} 

    wavelength

  .. _/NXvelocity_selector/wavelength_spread-field:

  .. index:: wavelength_spread (field)

  **wavelength_spread**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_WAVELENGTH <NX_WAVELENGTH>`} 

    deviation FWHM /Wavelength

  .. _/NXvelocity_selector/depends_on-field:

  .. index:: depends_on (field)

  **depends_on**: (optional) :ref:`NX_CHAR <NX_CHAR>` :ref:`⤆ </NXcomponent/depends_on-field>`

    .. collapse::   Add a definition for the reference point of a velocity selector. ...

        .. todo::
          Add a definition for the reference point of a velocity selector.

  .. _/NXvelocity_selector/geometry-group:

  **geometry**: (optional) :ref:`NXgeometry` 


    .. index:: deprecated


    **DEPRECATED**: Use the field `depends_on` and :ref:`NXtransformations` to position the velocity selector and NXoff_geometry to describe its shape instead


  .. _/NXvelocity_selector/OFF_GEOMETRY-group:

  :bolditalic:`OFF_GEOMETRY`: (optional) :ref:`NXoff_geometry` 

    This group describes the shape of the beam line component


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

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


* :ref:`/NXvelocity_selector/depends_on-field </NXvelocity_selector/depends_on-field>`
* :ref:`/NXvelocity_selector/geometry-group </NXvelocity_selector/geometry-group>`
* :ref:`/NXvelocity_selector/height-field </NXvelocity_selector/height-field>`
* :ref:`/NXvelocity_selector/length-field </NXvelocity_selector/length-field>`
* :ref:`/NXvelocity_selector/num-field </NXvelocity_selector/num-field>`
* :ref:`/NXvelocity_selector/OFF_GEOMETRY-group </NXvelocity_selector/OFF_GEOMETRY-group>`
* :ref:`/NXvelocity_selector/radius-field </NXvelocity_selector/radius-field>`
* :ref:`/NXvelocity_selector/rotation_speed-field </NXvelocity_selector/rotation_speed-field>`
* :ref:`/NXvelocity_selector/spwidth-field </NXvelocity_selector/spwidth-field>`
* :ref:`/NXvelocity_selector/table-field </NXvelocity_selector/table-field>`
* :ref:`/NXvelocity_selector/twist-field </NXvelocity_selector/twist-field>`
* :ref:`/NXvelocity_selector/type-field </NXvelocity_selector/type-field>`
* :ref:`/NXvelocity_selector/wavelength-field </NXvelocity_selector/wavelength-field>`
* :ref:`/NXvelocity_selector/wavelength_spread-field </NXvelocity_selector/wavelength_spread-field>`
* :ref:`/NXvelocity_selector/width-field </NXvelocity_selector/width-field>`

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