3.3.1.1. NXaperture

Status:

base class, extends NXobject

Description:

A beamline aperture. ...

A beamline aperture.

Note, the group was incorrectly documented as deprecated, but it is not and it is in common use.

Symbols:

No symbol table

Groups cited:

NXgeometry, NXnote, 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.

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.

The reference point of the aperture is its center in the x and y axis. The reference point on the z axis is the surface of the aperture pointing towards the source.

In complex (asymmetic) geometries an NXoff_geometry group can be used to provide an unambiguous reference.

../../_images/aperture.png

material: (optional) NX_CHAR

Absorbing material of the aperture

description: (optional) NX_CHAR

Description of aperture

TRANSFORMATIONS: (optional) NXtransformations

OFF_GEOMETRY: (optional) NXoff_geometry

Use this group to describe the shape of the aperture

GEOMETRY: (optional) NXgeometry

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

location and shape of aperture ...

location and shape of aperture

BLADE_GEOMETRY: (optional) NXgeometry

DEPRECATED: Use NXoff_geometry instead to describe the shape of the aperture

location and shape of each blade

NOTE: (optional) NXnote

describe any additional information in a note

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/NXaperture.nxdl.xml