NXsample¶
Status:
base class, extends NXobject
Description:
Any information on the sample.
This could include scanned variables that are associated with one of the data dimensions, e.g. the magnetic field, or logged data, e.g. monitored temperature vs elapsed time.
Symbols:
symbolic array lengths to be coordinated between various fields
n_comp: number of compositions
n_Temp: number of temperatures
n_eField: number of values in applied electric field
n_mField: number of values in applied magnetic field
n_pField: number of values in applied pressure field
n_sField: number of values in applied stress field
- Groups cited:
NXbeam, NXdata, NXenvironment, NXgeometry, NXlog, NXnote, NXpositioner, NXsample_component, NXtransformations
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.
name: (optional) NX_CHAR
Descriptive name of sample
chemical_formula: (optional) NX_CHAR
The chemical formula specified using CIF conventions. Abbreviated version of CIF standard:
Only recognized element symbols may be used.
Each element symbol is followed by a ‘count’ number. A count of ‘1’ may be omitted.
A space or parenthesis must separate each cluster of (element symbol + count).
Where a group of elements is enclosed in parentheses, the multiplier for the group must follow the closing parentheses. That is, all element and group multipliers are assumed to be printed as subscripted numbers.
Unless the elements are ordered in a manner that corresponds to their chemical structure, the order of the elements within any group or moiety depends on whether or not carbon is present.
If carbon is present, the order should be:
C, then H, then the other elements in alphabetical order of their symbol.
If carbon is not present, the elements are listed purely in alphabetic order of their symbol.
This is the Hill system used by Chemical Abstracts.
temperature: (optional) NX_FLOAT (Rank: anyRank, Dimensions: [n_Temp]) {units=NX_TEMPERATURE}
Sample temperature. This could be a scanned variable
electric_field: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_eField]) {units=NX_VOLTAGE}
magnetic_field: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_mField]) {units=NX_ANY}
stress_field: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_sField]) {units=NX_ANY}
pressure: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_pField]) {units=NX_PRESSURE}
Applied pressure
changer_position: (optional) NX_INT {units=NX_UNITLESS}
Sample changer position
unit_cell_abc: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_LENGTH}
Crystallography unit cell parameters a, b, and c
unit_cell_alphabetagamma: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_ANGLE}
Crystallography unit cell parameters alpha, beta, and gamma
unit_cell: (optional) NX_FLOAT (Rank: 2, Dimensions: [n_comp, 6]) {units=NX_LENGTH}
Unit cell parameters (lengths and angles)
unit_cell_volume: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_VOLUME}
Volume of the unit cell
sample_orientation: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_ANGLE}
This will follow the Busing-Levy convention:
Busing and H. A. Levy (1967). Acta Cryst. 22, 457-464
orientation_matrix: (optional) NX_FLOAT (Rank: 3, Dimensions: [n_comp, 3, 3])
Orientation matrix of single crystal sample using Busing-Levy convention:
Busing and H. A. Levy (1967). Acta Cryst. 22, 457-464
ub_matrix: (optional) NX_FLOAT (Rank: 3, Dimensions: [n_comp, 3, 3])
UB matrix of single crystal sample using Busing-Levy convention:
Busing and H. A. Levy (1967). Acta Cryst. 22, 457-464.
This is the multiplication of the orientation_matrix, given above, with the \(B\) matrix which can be derived from the lattice constants.
mass: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_MASS}
Mass of sample
density: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_MASS_DENSITY}
Density of sample
relative_molecular_mass: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_MASS}
Relative Molecular Mass of sample
type: (optional) NX_CHAR
Any of these values:
sample
sample+can
can
sample+buffer
buffer
calibration sample
normalisation sample
simulated data
none
sample environment
situation: (optional) NX_CHAR
The atmosphere will be one of the components, which is where its details will be stored; the relevant components will be indicated by the entry in the sample_component member.
Any of these values:
air
vacuum
inert atmosphere
oxidising atmosphere
reducing atmosphere
sealed can
other
description: (optional) NX_CHAR
Description of the sample
preparation_date: (optional) NX_DATE_TIME
Date of preparation of the sample
component: (optional) NX_CHAR (Rank: 1, Dimensions: [n_comp])
Details of the component of the sample and/or can
sample_component: (optional) NX_CHAR (Rank: 1, Dimensions: [n_comp])
Type of component
Any of these values:
sample
|can
|atmosphere
|kit
concentration: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_MASS_DENSITY}
Concentration of each component
volume_fraction: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp])
Volume fraction of each component
scattering_length_density: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_comp]) {units=NX_SCATTERING_LENGTH_DENSITY}
Scattering length density of each component
unit_cell_class: (optional) NX_CHAR
In case it is all we know and we want to record/document it
Any of these values:
triclinic
monoclinic
orthorhombic
tetragonal
rhombohedral
hexagonal
cubic
space_group: (optional) NX_CHAR (Rank: 1, Dimensions: [n_comp])
Crystallographic space group
point_group: (optional) NX_CHAR (Rank: 1, Dimensions: [n_comp])
Crystallographic point group, deprecated if space_group present
path_length: (optional) NX_FLOAT {units=NX_LENGTH}
Path length through sample/can for simple case when it does not vary with scattering direction
path_length_window: (optional) NX_FLOAT {units=NX_LENGTH}
Thickness of a beam entry/exit window on the can (mm). It is assumed to be the same for entry and exit
thickness: (optional) NX_FLOAT {units=NX_LENGTH}
sample thickness
sample_id: (optional) NX_CHAR
Identification number or signatures of the sample used.
state: (optional) NX_CHAR
Physical state of the sample
purity: (optional) NX_FLOAT {units=NX_UNITLESS}
Chemical purity of the sample
orientation: (optional) NX_CHAR
Surface termination of the sample (if crystalline)
layer: (optional) NX_CHAR
Number of layers of the sample (e.g. bulk, monolayer, pentalayer, etc.)
chemical_name: (optional) NX_CHAR
Full chemical name of the sample
chem_id_cas: (optional) NX_CHAR
CAS registry number of the sample chemical content.
gas: (optional) NX_CHAR
Gases might be fluxed on the surface for various reasons. Chemical designation, or residual.
gas_pressure: (optional) NX_NUMBER {units=NX_PRESSURE}
In the case of a fixed pressure measurement this is the scalar pressure. In the case of an experiment in which pressure changes, or anyway is recorded, this is an array of length m of pressures.
surface_dopant: (optional) NX_CHAR
Element of evaporated surface dopant such as alkali or other
surface_dopant_coverage: (optional) NX_FLOAT {units=NX_LENGTH}
Nominal thickness of the evaporated dopant
bias: (optional) NX_FLOAT {units=NX_VOLTAGE}
Voltage applied to sample and sample holder.
growth_method: (optional) NX_CHAR
Sample growth method (e. g. molecular beam epitaxy, chemical vapor deposition etc.)
vendor: (optional) NX_CHAR
Name of the sample vendor (company or research group)
substrate_material: (optional) NX_CHAR
Material of the substrate in direct contact with the sample.
substrate_state: (optional) NX_CHAR
Physical state of the substrate, similar options to sample_state
drain_current: (optional) NX_FLOAT {units=NX_CURRENT}
Current to neutralize the photoemission current. This field may also be found in NXmanpulator if present.
bias_voltage: (optional) NX_FLOAT {units=NX_VOLTAGE}
Possible bias of the sample with respect to analyser ground. This field may also be found as sample_bias in NXmanipulator if present.
external_DAC: (optional) NX_FLOAT {units=NX_ANY}
value sent to user’s sample setup
short_title: (optional) NX_CHAR
20 character fixed length sample description for legends
rotation_angle: (optional) NX_FLOAT {units=NX_ANGLE}
Optional rotation angle for the case when the powder diagram has been obtained through an omega-2theta scan like from a traditional single detector powder diffractometer
x_translation: (optional) NX_FLOAT {units=NX_LENGTH}
Translation of the sample along the X-direction of the laboratory coordinate system
distance: (optional) NX_FLOAT {units=NX_LENGTH}
Translation of the sample along the Z-direction of the laboratory coordinate system
depends_on: (optional) NX_CHAR
Refers to the last transformation specifying the positon of the manipulator in the NXtransformations chain.
geometry: (optional) NXgeometry
The position and orientation of the center of mass of the sample
BEAM: (optional) NXbeam
Details of beam incident on sample - used to calculate sample/beam interaction point
SAMPLE_COMPONENT: (optional) NXsample_component
One group per sample component This is the perferred way of recording per component information over the n_comp arrays
sample_history: (optional) NXnote
A descriptor to keep track of the treatment of the sample before entering the photoemission experiment. Ideally, a full report of the previous operations, in any format (NXnote allows to add pictures, audio, movies). Alternatively, a reference to the location or a unique identifier or other metadata file. In the case these are not available, free-text description
notes: (optional) NXnote
Further notes.
transmission: (optional) NXdata
As a function of Wavelength
temperature: (optional) NXlog
temperature.value is a link to e.g. temperature_env.sensor1.value
temperature_log: (optional) NXlog
temperature_log.value is a link to e.g. temperature_env.sensor1.value_log.value
temperature_env: (optional) NXenvironment
Additional sample temperature environment information
magnetic_field: (optional) NXlog
magnetic_field.value is a link to e.g. magnetic_field_env.sensor1.value
magnetic_field_log: (optional) NXlog
magnetic_field_log.value is a link to e.g. magnetic_field_env.sensor1.value_log.value
magnetic_field_env: (optional) NXenvironment
Additional sample magnetic environment information
external_ADC: (optional) NXlog
logged value (or logic state) read from user’s setup
POSITIONER: (optional) NXpositioner
Any positioner (motor, PZT, …) used to locate the sample
TRANSFORMATIONS: (optional) NXtransformations
Collection of axis-based translations and rotations to describe the location and geometry of the manipulator as a component in the instrument. Conventions from the NXtransformations base class are used. In principle, the McStas coordinate system is used. The first transformation has to point either to another component of the system or . (for pointing to the reference frame) to relate it relative to the experimental setup. Typically, the components of a system should all be related relative to each other and only one component should relate to the reference coordinate system.
Hypertext Anchors¶
List of hypertext anchors for all groups, fields, attributes, and links defined in this class.