3.3.1.57. NXvelocity_selector

Status:

base class, extends NXobject

Description:

A neutron velocity selector

Symbols:

No symbol table

Groups cited:

NXgeometry, NXoff_geometry, NXtransformations

Structure:

@default: (optional) NX_CHAR

Declares which child group contains a path leading ...

Declares which child group contains a path leading to a 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.

type: (optional) NX_CHAR

velocity selector type

rotation_speed: (optional) NX_FLOAT {units=NX_FREQUENCY}

velocity selector rotation speed

radius: (optional) NX_FLOAT {units=NX_LENGTH}

radius at beam centre

spwidth: (optional) NX_FLOAT {units=NX_LENGTH}

spoke width at beam centre

length: (optional) NX_FLOAT {units=NX_LENGTH}

rotor length

num: (optional) NX_INT {units=NX_UNITLESS}

number of spokes/lamella

twist: (optional) NX_FLOAT {units=NX_ANGLE}

twist angle along axis

table: (optional) NX_FLOAT {units=NX_ANGLE}

offset vertical angle

height: (optional) NX_FLOAT {units=NX_LENGTH}

input beam height

width: (optional) NX_FLOAT {units=NX_LENGTH}

input beam width

wavelength: (optional) NX_FLOAT {units=NX_WAVELENGTH}

wavelength

wavelength_spread: (optional) NX_FLOAT {units=NX_WAVELENGTH}

deviation FWHM /Wavelength

depends_on: (optional) NX_CHAR

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.

geometry: (optional) NXgeometry

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

OFF_GEOMETRY: (optional) NXoff_geometry

This group describes the shape of the beam line component

TRANSFORMATIONS: (optional) NXtransformations

Hypertext Anchors

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

NXDL Source:

https://github.com/nexusformat/definitions/blob/main/base_classes/NXvelocity_selector.nxdl.xml