4.3.1.30. NXmirror

Status:

base class, extends NXobject

Description:

A beamline mirror or supermirror.

Symbols:

No symbol table

Groups cited:

NXdata, NXgeometry, NXoff_geometry, NXshape, NXtransformations

Structure:

@default: (optional) NX_CHAR

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:

  • single: mirror with a single material as a reflecting surface

  • multi: mirror with stacked, multiple layers as a reflecting surface

description: (optional) NX_CHAR

description of this mirror

incident_angle: (optional) NX_FLOAT {units=NX_ANGLE}

bend_angle_x: (optional) NX_FLOAT {units=NX_ANGLE}

bend_angle_y: (optional) NX_FLOAT {units=NX_ANGLE}

interior_atmosphere: (optional) NX_CHAR

Any of these values: vacuum | helium | argon

external_material: (optional) NX_CHAR

external material outside substrate

m_value: (optional) NX_FLOAT {units=NX_UNITLESS}

The m value for a supermirror, which defines the supermirror regime in multiples of the critical angle of Nickel.

substrate_material: (optional) NX_CHAR

substrate_density: (optional) NX_FLOAT {units=NX_MASS_DENSITY}

substrate_thickness: (optional) NX_FLOAT {units=NX_LENGTH}

coating_material: (optional) NX_CHAR

substrate_roughness: (optional) NX_FLOAT {units=NX_LENGTH}

coating_roughness: (optional) NX_FLOAT {units=NX_LENGTH}

even_layer_material: (optional) NX_CHAR

even_layer_density: (optional) NX_FLOAT {units=NX_MASS_DENSITY}

odd_layer_material: (optional) NX_CHAR

odd_layer_density: (optional) NX_FLOAT {units=NX_MASS_DENSITY}

layer_thickness: (optional) NX_FLOAT {units=NX_LENGTH}

An array describing the thickness of each layer

depends_on: (optional) NX_CHAR

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.

Given a flat mirror, the reference plane is the plane which contains the “entry” surface of the mirror. The reference point of the mirror in the x and y axis is the centre of the mirror on that plane. The reference plane is orthogonal to the z axis and the location of this plane is the reference point on the z axis. The mirror faces negative z values.

../../_images/mirror.png

GEOMETRY: (optional) NXgeometry

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

reflectivity: (optional) NXdata

Reflectivity as function of wavelength

shape: (optional) NXshape

DEPRECATED: Use NXoff_geometry instead

A NXshape group describing the shape of the mirror

figure_data: (optional) NXdata

Numerical description of the surface figure of the mirror.

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 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/NXmirror.nxdl.xml