.. 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 =================== .. 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 **Status**: base class, extends :ref:`NXobject` **Description**: A neutron velocity selector **Symbols**: No symbol table **Groups cited**: :ref:`NXgeometry`, :ref:`NXoff_geometry`, :ref:`NXtransformations` .. index:: NXgeometry (base class); used in base class, NXoff_geometry (base class); used in base class, NXtransformations (base class); used in base class **Structure**: .. _/NXvelocity_selector@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. .. _/NXvelocity_selector/type-field: .. index:: type (field) **type**: (optional) :ref:`NX_CHAR ` velocity selector type .. _/NXvelocity_selector/rotation_speed-field: .. index:: rotation_speed (field) **rotation_speed**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_FREQUENCY `} velocity selector rotation speed .. _/NXvelocity_selector/radius-field: .. index:: radius (field) **radius**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} radius at beam centre .. _/NXvelocity_selector/spwidth-field: .. index:: spwidth (field) **spwidth**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} spoke width at beam centre .. _/NXvelocity_selector/length-field: .. index:: length (field) **length**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} rotor length .. _/NXvelocity_selector/num-field: .. index:: num (field) **num**: (optional) :ref:`NX_INT ` {units=\ :ref:`NX_UNITLESS `} number of spokes/lamella .. _/NXvelocity_selector/twist-field: .. index:: twist (field) **twist**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_ANGLE `} twist angle along axis .. _/NXvelocity_selector/table-field: .. index:: table (field) **table**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_ANGLE `} offset vertical angle .. _/NXvelocity_selector/height-field: .. index:: height (field) **height**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} input beam height .. _/NXvelocity_selector/width-field: .. index:: width (field) **width**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_LENGTH `} input beam width .. _/NXvelocity_selector/wavelength-field: .. index:: wavelength (field) **wavelength**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_WAVELENGTH `} wavelength .. _/NXvelocity_selector/wavelength_spread-field: .. index:: wavelength_spread (field) **wavelength_spread**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_WAVELENGTH `} deviation FWHM /Wavelength .. _/NXvelocity_selector/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. .. 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: **OFF_GEOMETRY**: (optional) :ref:`NXoff_geometry` This group describes the shape of the beam line component .. _/NXvelocity_selector/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:`/NXvelocity_selector/depends_on-field ` * :ref:`/NXvelocity_selector/geometry-group ` * :ref:`/NXvelocity_selector/height-field ` * :ref:`/NXvelocity_selector/length-field ` * :ref:`/NXvelocity_selector/num-field ` * :ref:`/NXvelocity_selector/OFF_GEOMETRY-group ` * :ref:`/NXvelocity_selector/radius-field ` * :ref:`/NXvelocity_selector/rotation_speed-field ` * :ref:`/NXvelocity_selector/spwidth-field ` * :ref:`/NXvelocity_selector/table-field ` * :ref:`/NXvelocity_selector/TRANSFORMATIONS-group ` * :ref:`/NXvelocity_selector/twist-field ` * :ref:`/NXvelocity_selector/type-field ` * :ref:`/NXvelocity_selector/wavelength-field ` * :ref:`/NXvelocity_selector/wavelength_spread-field ` * :ref:`/NXvelocity_selector/width-field ` * :ref:`/NXvelocity_selector@default-attribute ` **NXDL Source**: https://github.com/nexusformat/definitions/blob/main/base_classes/NXvelocity_selector.nxdl.xml