base class, extends NXobject


A beamline aperture. This group is deprecated, use NXslit instead.


No symbol table

Groups cited:

NXgeometry, NXnote, NXtransformations


@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.

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.

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.


material: (optional) NX_CHAR

Absorbing material of the aperture

description: (optional) NX_CHAR

Description of aperture

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.

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

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: