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

.. index::
    ! NXoptical_system_em (base class)
    ! optical_system_em (base class)
    see: optical_system_em (base class); NXoptical_system_em

.. _NXoptical_system_em:

===================
NXoptical_system_em
===================

**Status**:

  base class, extends :ref:`NXobject`

**Description**:

  A container for qualifying an electron optical system.

**Symbols**:

  No symbol table

**Groups cited**:
  none

**Structure**:

  .. _/NXoptical_system_em/camera_length-field:

  .. index:: camera_length (field)

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

    .. collapse:: Citing the JEOL TEM glossary this is *an effective distance from a specimen ...

        Citing the JEOL TEM glossary this is *an effective distance from a specimen
        to a plane where an observed diffraction pattern is formed*.

  .. _/NXoptical_system_em/magnification-field:

  .. index:: magnification (field)

  **magnification**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_DIMENSIONLESS <NX_DIMENSIONLESS>`} 

    .. collapse:: The factor of enlargement of the apparent size, ...

        The factor of enlargement of the apparent size,
        not the physical size, of an object.

  .. _/NXoptical_system_em/defocus-field:

  .. index:: defocus (field)

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

    .. collapse:: The defocus aberration constant (oftentimes referred to as C_1_0). ...

        The defocus aberration constant (oftentimes referred to as C_1_0).
        See respective details in :ref:`NXaberration` class instances.

  .. _/NXoptical_system_em/semi_convergence_angle-field:

  .. index:: semi_convergence_angle (field)

  **semi_convergence_angle**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_ANGLE <NX_ANGLE>`} 

    .. collapse:: Citing the JEOL TEM glossary this is the value *when a cone shaped, ...

        Citing the JEOL TEM glossary this is the value *when a cone shaped,
        convergent electron beam illuminates a specimen, the semi-angle of the cone
        is termed convergence angle.*

  .. _/NXoptical_system_em/field_of_view-field:

  .. index:: field_of_view (field)

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

    .. collapse:: The extent of the observable parts of the specimen given the current ...

        The extent of the observable parts of the specimen given the current
        magnification and other settings of the instrument.

  .. _/NXoptical_system_em/working_distance-field:

  .. index:: working_distance (field)

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

    .. collapse:: Citing `Globalsino <https://www.globalsino.com/EM/page4586.html>`_ this is ...

        Citing `Globalsino <https://www.globalsino.com/EM/page4586.html>`_ this is
        *a distance between the specimen and the lower pole piece in SEM system*.

  .. _/NXoptical_system_em/beam_current-field:

  .. index:: beam_current (field)

  **beam_current**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_CURRENT <NX_CURRENT>`} 

    .. collapse:: Beam current as measured relevant for the illumination of the specimen. ...

        Beam current as measured relevant for the illumination of the specimen.
        Users should specify further details like how the beam current
        was measured using the beam_current_description field.

  .. _/NXoptical_system_em/beam_current_description-field:

  .. index:: beam_current_description (field)

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

    Specify further details how the beam current was measured or estimated.


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

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


* :ref:`/NXoptical_system_em/beam_current-field </NXoptical_system_em/beam_current-field>`
* :ref:`/NXoptical_system_em/beam_current_description-field </NXoptical_system_em/beam_current_description-field>`
* :ref:`/NXoptical_system_em/camera_length-field </NXoptical_system_em/camera_length-field>`
* :ref:`/NXoptical_system_em/defocus-field </NXoptical_system_em/defocus-field>`
* :ref:`/NXoptical_system_em/field_of_view-field </NXoptical_system_em/field_of_view-field>`
* :ref:`/NXoptical_system_em/magnification-field </NXoptical_system_em/magnification-field>`
* :ref:`/NXoptical_system_em/semi_convergence_angle-field </NXoptical_system_em/semi_convergence_angle-field>`
* :ref:`/NXoptical_system_em/working_distance-field </NXoptical_system_em/working_distance-field>`

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