NXspectrum_set_em_xray

Status:

base class, extends NXobject

Description:

Container for reporting a set of energy-dispersive X-ray spectra.

Virtually the most important case is that spectra are collected in a scanning microscope (SEM or STEM) for a collection of points. The majority of cases use simple d-dimensional regular scan pattern, such as single point, line profiles, or (rectangular) surface mappings. The latter pattern is the most frequently used.

For now the base class provides for scans for which the settings, binning, and energy resolution is the same for each scan point.

IUPAC instead of Siegbahn notation should be used.

Symbols:

n_y: Number of pixel per X-ray mapping in the slow direction

n_x: Number of pixel per X-ray mapping in the fast direction

n_photon_energy: Number of X-ray photon energy (bins)

n_elements: Number of identified elements

n_peaks: Number of peaks

Groups cited:

NXdata, NXion, NXpeak, NXprocess

Structure:

PROCESS: (optional) NXprocess

Details how X-ray spectra were processed from the detector readings.

source: (optional) NX_CHAR

Typically the name of the input, (vendor) file from which all the NXdata instances in this NXspectrum_set_em_xray were loaded during parsing to represent them in e.g. databases.

@version: (optional) NX_CHAR

An at least as strong as SHA256 hashvalue of the dataset/file which represents the source digitally to support provenance tracking.

program: (optional) NX_CHAR

Commercial or otherwise given name to the program which was used to process detector data into the X-ray spectra stack and summary.

@version: (optional) NX_CHAR

Program version plus build number, commit hash, or description of an ever persistent resource where the source code of the program and build instructions can be found so that the program can be configured in such a manner that the result file is ideally recreatable yielding the same results.

stack: (optional) NXdata

Collected X-ray spectra for all pixels of a rectangular region-of-interest. This representation supports rectangular scan pattern.

@long_name: (optional) NX_CHAR

X-ray photon counts

counts: (optional) NX_UINT (Rank: 3, Dimensions: [n_y, n_x, n_photon_energy]) {units=NX_UNITLESS}

ypos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_y]) {units=NX_LENGTH}

@long_name: (optional) NX_CHAR

Label for the y axis

xpos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_x]) {units=NX_LENGTH}

@long_name: (optional) NX_CHAR

Label for the x axis

photon_energy: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_photon_energy]) {units=NX_ENERGY}

@long_name: (optional) NX_CHAR

X-ray energy

summary: (optional) NXdata

Accumulated X-ray spectrum over all pixels of a rectangular region-of-interest. This representation supports rectangular scan pattern.

@long_name: (optional) NX_CHAR

X-ray photon counts

counts: (optional) NX_UINT (Rank: 1, Dimensions: [n_photon_energy]) {units=NX_UNITLESS}

photon_energy: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_photon_energy]) {units=NX_ENERGY}

@long_name: (optional) NX_CHAR

X-ray energy

indexing: (optional) NXprocess

Details about computational steps how peaks were indexed as elements.

program: (optional) NX_CHAR

Given name of the program that was used to perform this computation.

@version: (optional) NX_CHAR

Program version plus build number, commit hash, or description of an ever persistent resource where the source code of the program and build instructions can be found so that the program can be configured in such a manner that the result file is ideally recreatable yielding the same results.

element_names: (optional) NX_CHAR (Rank: 1, Dimensions: [n_elements])

List of the names of identified elements.

PEAK: (optional) NXpeak

Name and location of each X-ray line which was indexed as a known ion. For each ion an NXion instance should be created which specifies the origin of the signal. For each ion also the relevant IUPAC notation X-ray lines should be specified.

ION: (optional) NXion

iupac_line_names: (optional) NX_CHAR

IUPAC notation identifier of the line which the peak represents.

This can be a list of IUPAC notations for (the seldom) case that multiple lines are group with the same peak.

composition_map: (optional) NXprocess

Individual element-specific EDX/EDS/EDXS/SXES mapping

A composition map is an image whose intensities for each pixel are the accumulated X-ray quanta under the curve(s) of a set of peaks.

program: (optional) NX_CHAR

Given name of the program that was used to perform this computation.

@version: (optional) NX_CHAR

Program version plus build number, commit hash, or description of an ever persistent resource where the source code of the program and build instructions can be found so that the program can be configured in such a manner that the result file is ideally recreatable yielding the same results.

peaks: (optional) NX_CHAR (Rank: 1, Dimensions: [n_peaks])

A list of strings of named instances of NXpeak from indexing whose X-ray quanta where accumulated for each pixel.

name: (optional) NX_CHAR

Human-readable, given name to the image.

DATA: (optional) NXdata

Individual element-specific maps. Individual maps should each be a group and be named according to element_names.

@long_name: (optional) NX_CHAR

Accumulated X-ray photon counts

counts: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_y, n_x]) {units=NX_UNITLESS}

ypos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_y]) {units=NX_LENGTH}

@long_name: (optional) NX_CHAR

Label for the y axis

xpos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_x]) {units=NX_LENGTH}

@long_name: (optional) NX_CHAR

Label for the x axis

Hypertext Anchors

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

NXDL Source:

https://github.com/FAIRmat-Experimental/nexus_definitions/tree/fairmat/contributed_definitions/NXspectrum_set_em_xray.nxdl.xml