2.3.3.1.4. NXbeam_stop

Status:

base class, extends NXobject

Description:

A device that blocks the beam completely, usually to protect a detector. ...

A device that blocks the beam completely, usually to protect a detector.

Beamstops and their positions are important for SANS and SAXS experiments.

Symbols:

No symbol table

Groups cited:

NXcylindrical_geometry, 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.

description: (optional) NX_CHAR

description of beamstop ...

description of beamstop

Any of these values: circular | rectangular

size: (optional) NX_FLOAT {units=NX_LENGTH}

Size of beamstop. If this is not sufficient to describe the beam stop use ...

Size of beamstop. If this is not sufficient to describe the beam stop use NXoff_geometry instead.

x: (optional) NX_FLOAT {units=NX_LENGTH}

x position of the beamstop in relation to the detector. ...

x position of the beamstop in relation to the detector. Note, it is recommended to use NXtransformations instead.

y: (optional) NX_FLOAT {units=NX_LENGTH}

y position of the beamstop in relation to the detector. ...

y position of the beamstop in relation to the detector. Note, it is recommended to use NXtransformations instead.

distance_to_detector: (optional) NX_FLOAT {units=NX_LENGTH}

distance of the beamstop to the detector. ...

distance of the beamstop to the detector. Note, it is recommended to use NXtransformations instead.

status: (optional) NX_CHAR

Any of these values: in | out

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

../../_images/beam_stop.png

GEOMETRY: (optional) NXgeometry

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

engineering shape, orientation and position of the beam stop.

OFF_GEOMETRY: (optional) NXoff_geometry

This group describes the shape of the beam line component

CYLINDRICAL_GEOMETRY: (optional) NXcylindrical_geometry

This group is an alternative to NXoff_geometry for describing the shape ...

This group is an alternative to NXoff_geometry for describing the shape of the beam stop.

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/FAIRmat-NFDI/nexus_definitions/tree/fairmat/base_classes/NXbeam_stop.nxdl.xml