3.3.3.108. NXxas_trans

Status:

application definition (contribution), extends NXxas

Description:

In transmission, the linear attenuation coefficient or absorption ...

In transmission, the linear attenuation coefficient or absorption coefficient \(\mu(E)\) is given by the Beer-Lambert law:

\[\mu(E)t = -\ln(I/I_0)\]

where \(I\) is the intensity of the transmitted beam, \(I_0\) is the intensity of the incident beam, and \(t\) is the thickness of the sample.

The top-level intensity field contains the processed absorption coefficient. When the raw detector data and processing steps are available, they can be stored in the optional NXinstrument and NXprocess groups, enabling full reproducibility of the data reduction.

Symbols:

No symbol table

Groups cited:

NXcrystal, NXdetector, NXentry, NXinstrument, NXmonochromator, NXprocess, NXsource

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_trans

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

The absorption coefficient \(\mu(E)t = -\ln(I/I_0)\).

INSTRUMENT: (optional) NXinstrument ⤆

SOURCE: (required) NXsource ⤆

type: (required) NX_CHAR ⤆

name: (required) NX_CHAR ⤆

probe: (required) NX_CHAR ⤆

Obligatory value: x-ray

monochromator: (optional) NXmonochromator ⤆

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

crystal: (optional) NXcrystal ⤆

d_spacing: (required) NX_FLOAT {units=NX_LENGTH} ⤆

The spacing between crystal planes of the reflection

type: (required) NX_CHAR ⤆

Type or material of monochromating substance ...

Type or material of monochromating substance (Si, Ge, Multilayer).

reflection: (required) NX_INT (Rank: 1, Dimensions: [3]) {units=NX_UNITLESS} ⤆

Miller indices (hkl) values of nominal reflection

i0: (required) NXdetector ⤆

Detector measuring the incident beam intensity ...

Detector measuring the incident beam intensity \(I_0\).

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

itrans: (required) NXdetector ⤆

Detector measuring the transmitted beam intensity ...

Detector measuring the transmitted beam intensity \(I\).

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

iref: (optional) NXdetector ⤆

Detector measuring the reference intensity ...

Detector measuring the reference intensity \(I_{ref}\), placed after a reference sample (typically a metal foil).

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

PROCESS: (optional) NXprocess ⤆

Description of how :ref:`intensity ...

Description of how intensity was obtained from the raw detector data (i0, itrans, and iref). When present, it allows a third party to fully reproduce the data reduction.

program: (optional) NX_CHAR ⤆

Name of the program used for processing.

version: (optional) NX_CHAR ⤆

Version of the program used for processing.

date: (optional) NX_DATE_TIME ⤆

Date and time of processing.

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/contributed_definitions/NXxas_trans.nxdl.xml