3.3.1.51. NXsource¶
Status:
base class, extends NXobject
Description:
The neutron or x-ray storage ring/facility.
Symbols:
No symbol table
- Groups cited:
NXdata, NXgeometry, NXnote, NXoff_geometry, 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.
distance: (optional) NX_FLOAT {units=NX_LENGTH}
Effective distance from sample Distance as seen by radiation from sample. This number should be negative to signify that it is upstream of the sample.
name: (optional) NX_CHAR
type: (optional) NX_CHAR
type of radiation source (pick one from the enumerated list and spell exactly)
Any of these values:
Spallation Neutron Source
Pulsed Reactor Neutron Source
Reactor Neutron Source
Synchrotron X-ray Source
Pulsed Muon Source
Rotating Anode X-ray
Fixed Tube X-ray
UV Laser
Free-Electron Laser
Optical Laser
Ion Source
UV Plasma Source
Metal Jet X-rayprobe: (optional) NX_CHAR
type of radiation probe (pick one from the enumerated list and spell exactly)
Any of these values:
neutron
x-ray
muon
electron
ultraviolet
visible light
positron
protonpower: (optional) NX_FLOAT {units=NX_POWER}
Source power
emittance_x: (optional) NX_FLOAT {units=NX_EMITTANCE}
Source emittance (nm-rad) in X (horizontal) direction.
emittance_y: (optional) NX_FLOAT {units=NX_EMITTANCE}
Source emittance (nm-rad) in Y (horizontal) direction.
sigma_x: (optional) NX_FLOAT {units=NX_LENGTH}
particle beam size in x
sigma_y: (optional) NX_FLOAT {units=NX_LENGTH}
particle beam size in y
flux: (optional) NX_FLOAT {units=NX_FLUX}
Source intensity/area (example: s-1 cm-2)
energy: (optional) NX_FLOAT {units=NX_ENERGY}
Source energy. For storage rings, this would be the particle beam energy. For X-ray tubes, this would be the excitation voltage.
current: (optional) NX_FLOAT {units=NX_CURRENT}
Accelerator, X-ray tube, or storage ring current
voltage: (optional) NX_FLOAT {units=NX_VOLTAGE}
Accelerator voltage
frequency: (optional) NX_FLOAT {units=NX_FREQUENCY}
Frequency of pulsed source
period: (optional) NX_FLOAT {units=NX_PERIOD}
Period of pulsed source
target_material: (optional) NX_CHAR
Pulsed source target material
Any of these values:
Ta
W
depleted_U
enriched_U
Hg
Pb
Cnumber_of_bunches: (optional) NX_INT
For storage rings, the number of bunches in use.
bunch_length: (optional) NX_FLOAT {units=NX_TIME}
For storage rings, temporal length of the bunch
bunch_distance: (optional) NX_FLOAT {units=NX_TIME}
For storage rings, time between bunches
pulse_width: (optional) NX_FLOAT {units=NX_TIME}
temporal width of source pulse
mode: (optional) NX_CHAR
source operating mode
Any of these values:
Single Bunch: for storage rings
Multi Bunch: for storage ringstop_up: (optional) NX_BOOLEAN
Is the synchrotron operating in top_up mode?
last_fill: (optional) NX_NUMBER {units=NX_CURRENT}
For storage rings, the current at the end of the most recent injection.
@time: (optional) NX_DATE_TIME
date and time of the most recent injection.
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 source plane is its center in the x and y axis. The source is considered infinitely thin in the z axis.
notes: (optional) NXnote
any source/facility related messages/events that occurred during the experiment
bunch_pattern: (optional) NXdata
For storage rings, description of the bunch pattern. This is useful to describe irregular bunch patterns.
title: (optional) NX_CHAR
name of the bunch pattern
pulse_shape: (optional) NXdata
source pulse shape
geometry: (optional) NXgeometry
DEPRECATED: Use the field depends_on and NXtransformations to position the source and NXoff_geometry to describe its shape instead
“Engineering” location of source.
OFF_GEOMETRY: (optional) NXoff_geometry
This group describes the shape of the beam line component
distribution: (optional) NXdata
The wavelength or energy distribution of the source
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.