3.3.1.28. NXinsertion_device

Status:

base class, extends NXobject

Description:

An insertion device, as used in a synchrotron light source.

Symbols:

No symbol table

Groups cited:

NXdata, 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

Any of these values: undulator | wiggler

gap: (optional) NX_FLOAT {units=NX_LENGTH}

separation between opposing pairs of magnetic poles

taper: (optional) NX_FLOAT {units=NX_ANGLE}

angular of gap difference between upstream and downstream ends of the insertion device

phase: (optional) NX_FLOAT {units=NX_ANGLE}

poles: (optional) NX_INT {units=NX_UNITLESS}

number of poles

magnetic_wavelength: (optional) NX_FLOAT {units=NX_WAVELENGTH}

k: (optional) NX_FLOAT {units=NX_DIMENSIONLESS}

beam displacement parameter

length: (optional) NX_FLOAT {units=NX_LENGTH}

length of insertion device

power: (optional) NX_FLOAT {units=NX_POWER}

total power delivered by insertion device

energy: (optional) NX_FLOAT {units=NX_ENERGY}

energy of peak intensity in output spectrum

bandwidth: (optional) NX_FLOAT {units=NX_ENERGY}

bandwidth of peak energy

harmonic: (optional) NX_INT {units=NX_UNITLESS}

harmonic number of peak

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.

spectrum: (optional) NXdata

spectrum of insertion device

GEOMETRY: (optional) NXgeometry

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

“Engineering” position of insertion device

OFF_GEOMETRY: (optional) NXoff_geometry

This group describes the shape of the beam line component

TRANSFORMATIONS: (optional) NXtransformations

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.

NXDL Source:

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