.. auto-generated by dev_tools.docs.nxdl from the NXDL source base_classes/NXattenuator.nxdl.xml -- DO NOT EDIT .. index:: ! NXattenuator (base class) ! attenuator (base class) see: attenuator (base class); NXattenuator .. _NXattenuator: ============ NXattenuator ============ .. 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 device that reduces the intensity of a beam by attenuation. ... A device that reduces the intensity of a beam by attenuation. If uncertain whether to use :ref:`NXfilter` (band-pass filter) or :ref:`NXattenuator` (reduces beam intensity), then choose :ref:`NXattenuator`. **Symbols**: No symbol table **Groups cited**: :ref:`NXoff_geometry`, :ref:`NXtransformations` .. index:: NXtransformations (base class); used in base class, NXoff_geometry (base class); used in base class **Structure**: .. _/NXattenuator@default-attribute: .. index:: default (file attribute) **@default**: (optional) :ref:`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. .. _/NXattenuator/distance-field: .. index:: distance (field) **distance**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} Distance from sample. Note, it is recommended to use NXtransformations instead. .. _/NXattenuator/type-field: .. index:: type (field) **type**: (optional) :ref:`NX_CHAR ` Type or composition of attenuator, e.g. polythene .. _/NXattenuator/thickness-field: .. index:: thickness (field) **thickness**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} Thickness of attenuator along beam direction .. _/NXattenuator/scattering_cross_section-field: .. index:: scattering_cross_section (field) **scattering_cross_section**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_CROSS_SECTION `} Scattering cross section (coherent+incoherent) .. _/NXattenuator/absorption_cross_section-field: .. index:: absorption_cross_section (field) **absorption_cross_section**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_CROSS_SECTION `} Absorption cross section .. _/NXattenuator/attenuator_transmission-field: .. index:: attenuator_transmission (field) **attenuator_transmission**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_DIMENSIONLESS `} .. collapse:: The nominal amount of the beam that gets through ... The nominal amount of the beam that gets through (transmitted intensity)/(incident intensity) .. _/NXattenuator/status-field: .. index:: status (field) **status**: (optional) :ref:`NX_CHAR ` .. collapse:: In or out or moving of the beam ... In or out or moving of the beam Any of these values: ``in`` | ``out`` | ``moving`` .. _/NXattenuator/status@time-attribute: .. index:: time (field attribute) **@time**: (optional) :ref:`NX_DATE_TIME ` time stamp for this observation .. _/NXattenuator/depends_on-field: .. index:: depends_on (field) **depends_on**: (optional) :ref:`NX_CHAR ` .. collapse:: 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. The reference point of the attenuator is its center in the x and y axis. The reference point on the z axis is the surface of the attenuator pointing towards the source. In complex (asymmetic) geometries an NXoff_geometry group can be used to provide an unambiguous reference. .. image:: attenuator/attenuator.png :width: 40% .. _/NXattenuator/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. .. _/NXattenuator/shape-group: **shape**: (optional) :ref:`NXoff_geometry` Shape of this component. Particulary useful to define the origin for position and orientation in non-standard cases. Hypertext Anchors ----------------- List of hypertext anchors for all groups, fields, attributes, and links defined in this class. * :ref:`/NXattenuator/absorption_cross_section-field ` * :ref:`/NXattenuator/attenuator_transmission-field ` * :ref:`/NXattenuator/depends_on-field ` * :ref:`/NXattenuator/distance-field ` * :ref:`/NXattenuator/scattering_cross_section-field ` * :ref:`/NXattenuator/shape-group ` * :ref:`/NXattenuator/status-field ` * :ref:`/NXattenuator/status@time-attribute ` * :ref:`/NXattenuator/thickness-field ` * :ref:`/NXattenuator/TRANSFORMATIONS-group ` * :ref:`/NXattenuator/type-field ` * :ref:`/NXattenuator@default-attribute ` **NXDL Source**: https://github.com/nexusformat/definitions/blob/main/base_classes/NXattenuator.nxdl.xml