3.3.2.44. NXxas

Status:

application definition, extends NXobject

Description:

Application definition for X-ray absorption spectroscopy (XAS). ...

Application definition for X-ray absorption spectroscopy (XAS).

This definition contains the common fields shared by all XAS measurements: energy axis, processed intensity, element, edge, and sample information.

The measurement mode (transmission, fluorescence yield, electron yield, HERFD, etc.) is described by an optional mode group whose NeXus type is one of the mode base classes (NXtrans, NXtfy, NXpfy, NXherfd, NXtey, NXpey). The mode group holds all mode-specific raw data, detectors, and instrument geometry.

Symbols:

nEnergy: Number of energy data points

nChan: Number of raw data channels

Groups cited:

NXcollection, NXdata, NXedge, NXelement, NXentry, NXherfd, NXpey, NXpfy, NXsample, NXtey, NXtfy, NXtrans, NXuser

Structure:

ENTRY: (required) NXentry

definition: (required) NX_CHAR ⤆

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

Official NeXus NXDL schema to which this file conforms.

Obligatory value: NXxas

element: (required) NXelement

Excited element

edge: (required) NXedge

Absorption edge

calculated: (optional) NX_BOOLEAN {units=NX_UNITLESS}

Specify if the data comes from a calculation.

energy: (required) NX_FLOAT (Rank: 1, Dimensions: [nEnergy]) {units=NX_ENERGY}

The energy axis of the spectrum.

intensity: (required) NX_FLOAT (Rank: 1, Dimensions: [nEnergy]) {units=NX_ANY}

The processed absorption spectrum. The precise definition ...

The processed absorption spectrum. The precise definition depends on the acquisition mode (transmission, fluorescence yield, electron yield, etc.)

intensity_errors: (optional) NX_FLOAT (Rank: 1, Dimensions: [nEnergy]) {units=NX_ANY}

The errors associated with the intensity of the spectrum.

SAMPLE: (required) NXsample ⤆

name: (required) NX_CHAR ⤆

Descriptive name of the sample

mode: (required) Only one of the following groups may be present:

TRANS: NXtrans

TFY: NXtfy

PFY: NXpfy

HERFD: NXherfd

TEY: NXtey

PEY: NXpey

DATA: (optional) NXdata ⤆

Plot of the X-ray absorption intensity versus energy

energy: link (suggested target: /NXentry/energy)

intensity: link (suggested target: /NXentry/intensity)

COLLECTION: (optional) NXcollection ⤆

DATA: (optional) NXdata ⤆

Table like data structure common in the XAS domain.

data: (required) NX_NUMBER (Rank: 2, Dimensions: [nChan, nEnergy]) ⤆

columns: (required) NX_CHAR (Rank: 1, Dimensions: [nEnergy])

data_collector: (optional) NXuser

name: (required) NX_CHAR ⤆

orcid: (required) NX_CHAR

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/NXxas.nxdl.xml