3.3.1.3. NXbeam¶
Status:
base class, extends NXobject
Description:
Properties of the neutron or X-ray beam at a given location.
It will be referenced by beamline component groups within the NXinstrument group or by the NXsample group. Note that variables such as the incident energy could be scalar values or arrays. This group is especially valuable in storing the results of instrument simulations in which it is useful to specify the beam profile, time distribution etc. at each beamline component. Otherwise, its most likely use is in the NXsample group in which it defines the results of the neutron scattering by the sample, e.g., energy transfer, polarizations.
Symbols:
No symbol table
- Groups cited:
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}
Distance from sample
incident_energy[i]: (optional) NX_FLOAT {units=NX_ENERGY}
Energy on entering beamline component
final_energy[i]: (optional) NX_FLOAT {units=NX_ENERGY}
Energy on leaving beamline component
energy_transfer[i]: (optional) NX_FLOAT {units=NX_ENERGY}
Energy change caused by beamline component
incident_wavelength[i]: (optional) NX_FLOAT {units=NX_WAVELENGTH}
Wavelength on entering beamline component
incident_wavelength_spread[i]: (optional) NX_FLOAT {units=NX_WAVELENGTH}
Wavelength spread FWHM on entering component
incident_beam_divergence[2, j]: (optional) NX_FLOAT {units=NX_ANGLE}
Divergence of beam entering this component
extent[2, j]: (optional) NX_FLOAT {units=NX_LENGTH}
Size of the beam entering this component
final_wavelength[i]: (optional) NX_FLOAT {units=NX_WAVELENGTH}
Wavelength on leaving beamline component
incident_polarization[2, j]: (optional) NX_FLOAT {units=NX_ANY}
Polarization vector on entering beamline component
final_polarization[2, j]: (optional) NX_FLOAT {units=NX_ANY}
Polarization vector on leaving beamline component
final_wavelength_spread[i]: (optional) NX_FLOAT {units=NX_WAVELENGTH}
Wavelength spread FWHM of beam leaving this component
final_beam_divergence[2, j]: (optional) NX_FLOAT {units=NX_ANGLE}
Divergence FWHM of beam leaving this component
flux[i]: (optional) NX_FLOAT {units=NX_FLUX}
flux incident on beam plane area
DATA: (optional) NXdata
Distribution of beam with respect to relevant variable e.g. wavelength. This is mainly useful for simulations which need to store plottable information at each beamline component.
Hypertext Anchors¶
Table of hypertext anchors for all groups, fields, attributes, and links defined in this class.
documentation (reST source) anchor |
web page (HTML) anchor |
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