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

.. index::
    ! NXslit (base class)
    ! slit (base class)
    see: slit (base class); NXslit

.. _NXslit:

======
NXslit
======

..
    Contributors List

    .. |contrib_name| replace:: Aaron Brewster|phyy-nx|https://avatars.githubusercontent.com/u/13471434?v=4|2022-06-15

    .. |contrib_name| replace:: Pete R Jemian|prjemian|https://avatars.githubusercontent.com/u/2279984?v=4|2022-01-28

    .. |contrib_name| replace:: Peter Chang|PeterC-DLS|https://avatars.githubusercontent.com/u/1381719?v=4|2020-10-20

    .. |contrib_name| replace:: Tobias Richter|zjttoefs|https://avatars.githubusercontent.com/u/856440?v=4|2018-05-15

    .. |contrib_name| replace:: Joachim Wuttke (l)|jwuttke|https://avatars.githubusercontent.com/u/5262000?v=4|2014-08-26

**Status**:

  base class, extends :ref:`NXobject`

**Description**:

  .. collapse:: A simple slit. ...

      A simple slit.

      For more complex geometries, :ref:`NXaperture` should be used.

**Symbols**:

  No symbol table

**Groups cited**:
  :ref:`NXtransformations`

.. index:: NXtransformations (base class); used in base class

**Structure**:

  .. _/NXslit@default-attribute:

  .. index:: default (file attribute)

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

    .. collapse:: Declares which child group contains a path leading  ...

        .. 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.

  .. _/NXslit/depends_on-field:

  .. index:: depends_on (field)

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

    .. collapse:: Points to the path of the last element in the geometry chain that places ...

        Points to the path of the last element in the geometry chain that places
        this object in space. 
        When followed through that chain is supposed to end at an element depending
        on "." i.e. the origin of the coordinate system.
        If desired the location of the slit can also be described relative to
        an NXbeam, which will allow a simple description of a non-centred slit.

        The reference plane of the slit is orthogonal to the z axis and includes the
        surface that is the entry surface of the slit. The reference point of the slit
        is the centre of the slit opening in the x and y axis on the reference plane.
        The reference point on the z axis is the reference plane.

        .. image:: slit/slit.png
        	:width: 40%


  .. _/NXslit/x_gap-field:

  .. index:: x_gap (field)

  **x_gap**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`} 

    .. collapse:: Size of the gap opening in the first dimension of the local ...

        Size of the gap opening in the first dimension of the local
        coordinate system.

  .. _/NXslit/y_gap-field:

  .. index:: y_gap (field)

  **y_gap**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`} 

    .. collapse:: Size of the gap opening in the second dimension of the local ...

        Size of the gap opening in the second dimension of the local
        coordinate system.

  .. _/NXslit/TRANSFORMATIONS-group:

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

    .. collapse:: This is the group recommended for holding the chain of translation ...

        This is the group recommended for holding the chain of translation
        and rotation operations necessary to position the component within
        the instrument. The dependency chain may however traverse similar groups in
        other component groups.


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

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


* :ref:`/NXslit/depends_on-field </NXslit/depends_on-field>`
* :ref:`/NXslit/TRANSFORMATIONS-group </NXslit/TRANSFORMATIONS-group>`
* :ref:`/NXslit/x_gap-field </NXslit/x_gap-field>`
* :ref:`/NXslit/y_gap-field </NXslit/y_gap-field>`
* :ref:`/NXslit@default-attribute </NXslit@default-attribute>`

**NXDL Source**:
  https://github.com/nexusformat/definitions/blob/main/base_classes/NXslit.nxdl.xml