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

Structure:

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

Name of source

@short_name: (optional) NX_CHAR

short name for source, perhaps the acronym

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

probe: (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

  • proton

power: (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

  • C

number_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 rings

top_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.

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

“Engineering” location of source

distribution: (optional) NXdata

The wavelength or energy distribution of the source

NXDL Source:

https://github.com/nexusformat/definitions/blob/master/base_classes/NXsource.nxdl.xml