3.3.2.13. NXazint2d

Status:

application definition, extends NXobject

Description:

Application definition for data from two-dimensional area detectors that has bee ...

Application definition for data from two-dimensional area detectors that has been integrated azimuthally, with a certain radial binning in units of q or 2theta and with a binning around the azimuthal angle eta.

An example application that creates these files is documented here: https://maxiv-science.github.io/azint_writer/

Symbols:

The symbol(s) listed here will be used below to coordinate datasets with the same shape.

nImg: Number of integrated images

nRad: Number of radial bins

nRadEdge: Number of radial bin edges (nRad+1)

nEta: Number of azimuthal bins

nEtaEdge: Number of azimuthal bin edges (nEta+1)

Groups cited:

NXdata, NXentry, NXinstrument, NXmonitor, NXmonochromator, NXparameters, NXprocess, NXsource

Structure:

ENTRY: (required) NXentry

The ``NXsubentry`` or Multi-Method Data convention described here: ...

The NXsubentry or Multi-Method Data convention described here: https://manual.nexusformat.org/rules.html#table-nxsubentry should be used when different method (e.g. NXcanSAS or NXmonopd), NXazint1d or other NXazint2d data, integrated with different options, should be stored under the same NXentry.

In case of a single NXazint2d data processing the standard convention with the application definition directly under NXentry should be used.

@default: (optional) NX_CHAR ⤆

Declares which :ref:`NXdata` group ...

Declares which NXdata group contains the data to be shown by default. It is needed to resolve ambiguity when more than one NXdata group exists. The value is the name of the default NXdata group.

definition: (required) NX_CHAR ⤆

Official NeXus NXDL schema to which this file conforms. ...

Official NeXus NXDL schema to which this file conforms.

Obligatory value: NXazint2d

solid_angle_applied: (required) NX_BOOLEAN

is solid angle correction applied or not.

polarization_applied: (required) NX_BOOLEAN

is polarization correction applied or not.

normalization_applied: (required) NX_BOOLEAN

is a normalization correction applied or not. ...

is a normalization correction applied or not.

It indicates that integrated intensities and their errors were already divided by the appropriate normalization factors accounting for the effective number or weighted contribution of detector pixels to each integration bin.

monitor_applied: (optional) NX_BOOLEAN

is a monitor correction applied or not. ...

is a monitor correction applied or not.

The monitor correction accounts for external factors that are independent of the azimuthal integration process. Most commonly, this involves normalizing for fluctuations in the incident beam intensity or, where applicable, variations in exposure time.

INSTRUMENT: (required) NXinstrument ⤆

name: (required) NX_CHAR ⤆

Name of instrument (beamline) where data was collected.

MONOCHROMATOR: (required) NXmonochromator ⤆

wavelength: (required) NX_FLOAT {units=angstrom} ⤆

Wavelength in angstrom.

energy: (required) NX_FLOAT {units=keV} ⤆

Energy in keV.

SOURCE: (required) NXsource ⤆

name: (required) NX_CHAR ⤆

Name of laboratory where data was collected.

type: (required) NX_CHAR ⤆

Type of laboratory where data was collected.

probe: (required) NX_CHAR ⤆

Type of probe.

reduction: (required) NXprocess ⤆

program: (required) NX_CHAR ⤆

Name of the program that made this file.

version: (required) NX_CHAR ⤆

Version of the progam that made this file.

date: (required) NX_DATE_TIME ⤆

Date the file was created.

reference: (required) NX_CHAR

Citation or other references for the algorithm used in the processing.

note: (optional) NX_CHAR

Notes required to help interpret the data, e.g. on coordinate systems.

input: (required) NXparameters ⤆

Parameters should exactly match those required by the algorithm used in th ...

Parameters should exactly match those required by the algorithm used in the processing. For example, azint requires error_model, mask, n_splitting, poni, etc.

MONITOR: (optional) NXmonitor ⤆

Monitor data for example I_zero.

data: (required) NX_NUMBER (Rank: 1, Dimensions: [nImg]) ⤆

DATA: (required) NXdata ⤆

Azimuthally integrated data with radial binning in q or 2theta and with azimuthal binning.

@axes: (required) NX_CHAR ⤆

Obligatory value: ['.', 'azimuthal_axis', 'radial_axis']

@interpretation: (required) NX_CHAR

Obligatory value: image

@signal: (required) NX_CHAR ⤆

Obligatory value: I

I: (required) NX_NUMBER (Rank: 3, Dimensions: [nImg, nEta, nRad])

@long_name: (required) NX_CHAR

Obligatory value: intensity

@units: (required) NX_CHAR

Obligatory value: arbitrary units

I_errors: (optional) NX_NUMBER (Rank: 3, Dimensions: [nImg, nEta, nRad]) ⤆

@long_name: (optional) NX_CHAR

Obligatory value: estimated intensity error

@units: (optional) NX_CHAR

Obligatory value: arbitrary units

radial_axis: (required) NX_NUMBER (Rank: 1, Dimensions: [nRad]) ⤆

@long_name: (required) NX_CHAR ⤆

Any of these values: q | 2theta

@units: (required) NX_CHAR

Any of these values: NX_PER_LENGHT | NX_WAVENUMBER | NX_ANGLE

radial_axis_edges: (optional) NX_NUMBER (Rank: 1, Dimensions: [nRadEdge]) ⤆

@long_name: (required) NX_CHAR ⤆

Any of these values: q bin edges | 2theta bin edges

@units: (required) NX_CHAR

Any of these values: NX_PER_LENGTH | NX_WAVENUMBER | NX_ANGLE

norm: (optional) NX_NUMBER (Rank: 2, Dimensions: [nEta, nRad])

Values of the normalization correction. ...

Values of the normalization correction.

The normalization correction accounts for the effective number or weighted contribution of detector pixels to each integration bin.

Note: An important aspect of the normalization strategy is how polarization and solid angle corrections are incorporated, which can vary depending on the specific application, software, and its configuration options (see, for example, PyFAI documentation). Additionally, the normalization strategy may include a relative or absolute calibration factor. Two common normalization approaches are: “Relative normalization” to the PONI (Point Of Normal Incidence) pixel, and “Absolute calibration”, which yields the number of photons scattered by the sample in a given direction per unit solid angle. The type of the normalization strategy is not indicated on this level. It must be concluded from the software used or its parameters.

The monitor correction is not included in the normalization correction and it is specified separately.

@long_name: (required) NX_CHAR

Obligatory value:

  • effective number of pixels contributing to the corresponding bin

@units: (required) NX_CHAR

Obligatory value: arbitrary units

azimuthal_axis: (optional) NX_NUMBER (Rank: 1, Dimensions: [nEta])

@long_name: (required) NX_CHAR

Obligatory value: azimuthal bin center

@units: (required) NX_CHAR

Obligatory value: NX_ANGLE

azimuthal_axis_edges: (optional) NX_NUMBER (Rank: 1, Dimensions: [nEtaEdge])

@long_name: (required) NX_CHAR

Obligatory value: azimuthal bin edges

@units: (required) NX_CHAR

Obligatory value: NX_ANGLE

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source:

https://github.com/nexusformat/definitions/blob/main/applications/NXazint2d.nxdl.xml