2.3.3.3.153. NXmpes

Status:

application definition (contribution), extends NXobject

Description:

This is the most general application definition for ...

This is the most general application definition for photoemission experiments.

Groups and fields are named according to the ISO 18115-1:2023 specification as well as the IUPAC Recommendations 2020.

Symbols:

The symbols used in the schema to specify e.g. dimensions of arrays

n_transmission_function: Number of data points in the transmission function.

Groups cited:

NXactivity, NXactuator, NXaperture, NXbeam, NXcalibration, NXcollectioncolumn, NXcoordinate_system, NXdata, NXdistortion, NXelectron_detector, NXelectronanalyzer, NXenergydispersion, NXentry, NXenvironment, NXfabrication, NXfit, NXhistory, NXinstrument, NXlog, NXmanipulator, NXpid_controller, NXregistration, NXresolution, NXsample, NXsensor, NXsource, NXuser

Structure:

ENTRY: (required) NXentry

definition: (required) NX_CHAR ⤆

Obligatory value: NXmpes

@version: (required) NX_CHAR ⤆

title: (required) NX_CHAR ⤆

start_time: (required) NX_DATE_TIME ⤆

Datetime of the start of the measurement. ...

Datetime of the start of the measurement. Should be a ISO8601 date/time stamp. It is recommended to add an explicit time zone, otherwise the local time zone is assumed per ISO8601.

end_time: (recommended) NX_DATE_TIME ⤆

Datetime of the end of the measurement. ...

Datetime of the end of the measurement. Should be a ISO8601 date/time stamp. It is recommended to add an explicit time zone, otherwise the local time zone is assumed per ISO8601.

method: (recommended) NX_CHAR

Name of the experimental method. ...

Name of the experimental method.

If applicable, this name should match the terms given by Clause 11 of the ISO 18115-1:2023 specification.

Examples include:

  • X-ray photoelectron spectroscopy (XPS)

  • angle-resolved X-ray photoelectron spectroscopy (ARXPS)

  • ultraviolet photoelectron spectroscopy (UPS)

  • angle-resolved photoelectron spectroscopy (ARPES)

  • hard X-ray photoemission spectroscopy (HAXPES)

  • near ambient pressure X-ray photoelectron spectroscopy (NAPXPS)

  • photoelectron emission microscopy (PEEM)

  • electron spectroscopy for chemical analysis (ESCA)

  • time-resolved angle-resolved X-ray photoelectron spectroscopy (trARPES)

  • spin-resolved angle-resolved X-ray photoelectron spectroscopy (spin-ARPES)

  • momentum microscopy

transitions: (optional) NX_CHAR

List of strings representing the electronic core levels and Auger transition ...

List of strings representing the electronic core levels and Auger transitions probed in this MPES experiment.

In order for experiments to be comparable, the notation must follow a strict convention.

For core levels:

  • The element symbol (chemical symbol) is written first.

  • It is followed by a whitespace and then the electronic level (e.g., “1s”, “2p”, “3d”, etc.)

  • Fine-structure splitting levels must include the total angular momentum quantum number J, written as a fraction after the orbital label (e.g., “3d5/2”, “4f7/2”).

  • When relevant, fine-structure levels should be specified. If multiple fine-structure levels are probed, they should either be given explicitly or the generic level (e.g., “3d”, “4f”) can be used.

Examples of correct core level notation:

  • “C 1s”

  • “O 1s”

  • “Fe 2p”

  • “Fe 2p3/2”

  • “Fe 2p1/2”

  • “Au 4f”

  • “Au 4f5/2”

  • “Au 4f7/2”

For Auger transitions:

  • The element symbol (chemical symbol) is written first.

  • It is followed by a whitespace and the Auger transitions, which can include:

    • Explicit transitions (e.g., “KLL”, “LMM”) without fine-structure splitting

    • Explicit transitions (e.g., “KL1L2”, “LM1M2”) with fine-structure splitting

    • Simplified valence notation (e.g., “KVV”, “KLV”).

    • Combinations of the above (e.g. “KL1V”).

Examples of correct Auger transition notation:

  • “C KLL”

  • “O KLL”

  • “O KVV”

  • “O KL1L2”

Additional Allowed Entries:

Besides specific core levels and Auger transitions, the following broader spectral regions can also be listed:

  • “Fermi Edge”

  • “Valence Band”

  • “Survey”

Incorrect Notation Examples (Do Not Use):

  • “C1s” (missing space)

  • “O-1s” (incorrect separator)

  • “Fe2p” (missing space)

  • “Au4f7/2” (missing space)

  • “O-KVV” (incorrect separator)

  • “Fe 2p_3/2” (incorrect underscore)

  • “Fe 2p 3/2” (extra space between “p” and “3/2”)

COORDINATE_SYSTEM: (optional) NXcoordinate_system

Description of one coordinate systems that are specific to the setup ...

Description of one coordinate systems that are specific to the setup and the measurement geometry.

Multiple coordinate systems can be used if necessary.

USER: (recommended) NXuser ⤆

Contact information of at least the user of the instrument or the investigat ...

Contact information of at least the user of the instrument or the investigator who performed this experiment. Adding multiple users if relevant is recommended.

name: (required) NX_CHAR ⤆

Name of the user.

affiliation: (required) NX_CHAR ⤆

Name of the affiliation of the user at the time when the experiment was ...

Name of the affiliation of the user at the time when the experiment was performed.

INSTRUMENT: (required) NXinstrument ⤆

Description of the photoemission spectrometer and its individual parts. ...

Description of the photoemission spectrometer and its individual parts.

This concept is related to term 12.58 of the ISO 18115-1:2023 standard.

energy_resolution: (optional) NXresolution

Overall energy resolution of the photoemission instrument.

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: energy

type: (recommended) NX_CHAR ⤆

resolution: (required) NX_FLOAT {units=NX_ENERGY} ⤆

Minimum distinguishable energy separation in the energy spectra. ...

Minimum distinguishable energy separation in the energy spectra.

This concept is related to term 10.24 of the ISO 18115-1:2023 standard.

relative_resolution: (optional) NX_FLOAT ⤆

Ratio of the energy resolution of the photoemission spectrometer at a sp ...

Ratio of the energy resolution of the photoemission spectrometer at a specified energy value to that energy value.

This concept is related to term 10.7 ff. of the ISO 18115-1:2023 standard.

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

source_probe: (recommended) NXsource ⤆

The source used to generate the :ref:`beam_probe

The source used to generate the beam_probe.

Properties refer strictly to parameters of the source, not of the output beam. For example, the energy of the source is not the optical power of the beam, but the energy of the electron beam in a synchrotron or similar.

type: (required) NX_CHAR ⤆

Any of these values or a custom value (if you use a custom value, also set @custom=True):

  • Synchrotron X-ray Source

  • Rotating Anode X-ray

  • Fixed Tube X-ray

  • UV Laser

  • Free-Electron Laser

  • Optical Laser

  • UV Plasma Source

  • Metal Jet X-ray

  • HHG laser

  • UV lamp

  • Monochromatized electron source

name: (recommended) NX_CHAR ⤆

probe: (optional) NX_CHAR ⤆

associated_beam: (required) NX_CHAR

A reference to a beam emitted by this source. ...

A reference to a beam emitted by this source. Should be named with the same appendix, e.g., for source_probe it should refer to beam_probe.

Example:

  • /entry/instrument/source_probe/associated_beam = /entry/instrument/beam_probe

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

source_pump: (optional) NXsource ⤆

The source used to generate the :ref:`beam_pump

The source used to generate the beam_pump in pump-probe experiments.

Properties refer strictly to parameters of the source, not of the output beam.

type: (required) NX_CHAR ⤆

name: (recommended) NX_CHAR ⤆

probe: (optional) NX_CHAR ⤆

associated_beam: (required) NX_CHAR

A reference to a beam emitted by this source. ...

A reference to a beam emitted by this source. Should be named with the same appendix, e.g., for source_pump it should refer to beam_pump.

Example:

  • /entry/instrument/source_pump/associated_beam = /entry/instrument/beam_pump

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

source_TYPE: (optional) NXsource ⤆

Any other source used to generate a beam. ...

Any other source used to generate a beam.

This group is to be used for any additional beams that are not described by source_probe or source_pump.

Examples could be a low energy electron source for charge neutralization (see also flood_gun) or an additional laser source.

Properties refer strictly to parameters of the source, not of the output beam.

Note that the uppercase notation in source_TYPE means that multiple sources can be provided. The uppercase part can be substituted with any string that consists of alphanumeric characters, including both uppercase and lowercase letters from A to Z and numerical digits from 0 to 9. For example, in pump-probe experiments, it is possible to have both a source_laser and a source_electron.

type: (required) NX_CHAR ⤆

name: (recommended) NX_CHAR ⤆

probe: (optional) NX_CHAR ⤆

associated_beam: (required) NX_CHAR

A reference to a beam emitted by this source. ...

A reference to a beam emitted by this source. Should be named with the same appendix, e.g., for source_laser it should refer to beam_laser.

Example:

  • /entry/instrument/source_laser/associated_beam = /entry/instrument/beam_laser

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

beam_probe: (required) NXbeam ⤆

Properties of the probe beam at a given location. ...

Properties of the probe beam at a given location.

This is the beam that is used to facilitate the photoemission during MPES experiments.

distance: (recommended) NX_NUMBER {units=NX_LENGTH}

Distance between the point where the current NXbeam instance is evaluati ...

Distance between the point where the current NXbeam instance is evaluating the beam properties and the point where the beam interacts with the sample. For photoemission, the latter is the point where the the centre of the beam touches the sample surface.

incident_energy: (required) NX_FLOAT {units=NX_ENERGY} ⤆

incident_energy_spread: (recommended) NX_NUMBER {units=NX_ENERGY} ⤆

incident_polarization: (recommended) NX_NUMBER {units=NX_ANY} ⤆

extent: (recommended) NX_FLOAT ⤆

associated_source: (recommended) NX_CHAR

The source that emitted this beam. ...

The source that emitted this beam. Should be named with the same appendix, e.g., for beam_probe it should refer to source_probe. This should be specified if an associated source exists.

Example:

  • /entry/instrument/beam_probe/associated_source = /entry/instrument/source_probe

beam_pump: (optional) NXbeam ⤆

Properties of the pump beam at a given location. ...

Properties of the pump beam at a given location.

In pump-probe experiments, this is the beam that excites the system, initiating a change in its state. It sets the timing for the experiment by defining time zero in a pump-probe setup.

distance: (recommended) NX_NUMBER {units=NX_LENGTH}

Distance between the point where the current NXbeam instance is evaluati ...

Distance between the point where the current NXbeam instance is evaluating the beam properties and the point where the beam interacts with the sample. For photoemission, the latter is the point where the the centre of the beam touches the sample surface.

incident_energy: (required) NX_FLOAT {units=NX_ENERGY} ⤆

incident_energy_spread: (recommended) NX_NUMBER {units=NX_ENERGY} ⤆

incident_polarization: (recommended) NX_NUMBER {units=NX_ANY} ⤆

extent: (recommended) NX_FLOAT ⤆

associated_source: (recommended) NX_CHAR

The source that emitted this beam. ...

The source that emitted this beam. Should be named with the same appendix, e.g., for beam_pump it should refer to source_pump. This should be specified if an associated source exists.

Example:

  • /entry/instrument/beam_pump/associated_source = /entry/instrument/source_pump

beam_TYPE: (optional) NXbeam ⤆

Properties of any other beam at a given location. ...

Properties of any other beam at a given location.

This group is to be used for any additional beams that are not described by beam_probe or beam_pump.

Should be named with the same appendix as source_TYPE, e.g., for source_laser it should refer to beam_laser.

distance: (recommended) NX_NUMBER {units=NX_LENGTH}

Distance between the point where the current NXbeam instance is evaluati ...

Distance between the point where the current NXbeam instance is evaluating the beam properties and the point where the beam interacts with the sample. For photoemission, the latter is the point where the the centre of the beam touches the sample surface.

incident_energy: (required) NX_FLOAT {units=NX_ENERGY} ⤆

incident_energy_spread: (recommended) NX_NUMBER {units=NX_ENERGY} ⤆

incident_polarization: (recommended) NX_NUMBER {units=NX_ANY} ⤆

extent: (recommended) NX_FLOAT ⤆

associated_source: (recommended) NX_CHAR

The source that emitted this beam. ...

The source that emitted this beam. Should be named with the same appendix, e.g., for beam_laser it should refer to source_laser. This should be specified if an associated source exists.

Example:

  • /entry/instrument/beam_laser/associated_source = /entry/instrument/source_laser

ELECTRONANALYZER: (required) NXelectronanalyzer

description: (recommended) NX_CHAR ⤆

work_function: (recommended) NX_FLOAT {units=NX_ENERGY} ⤆

fast_axes: (recommended) NX_CHAR ⤆

slow_axes: (recommended) NX_CHAR ⤆

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

energy_resolution: (optional) NXresolution ⤆

type: (recommended) NX_CHAR ⤆

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: energy

resolution: (required) NX_FLOAT ⤆

transmission_function: (optional) NXdata ⤆

COLLECTIONCOLUMN: (required) NXcollectioncolumn ⤆

scheme: (required) NX_CHAR ⤆

Scheme of the electron collection column. ...

Scheme of the electron collection column.

Any of these values:

  • angular dispersive

  • spatial dispersive

  • momentum dispersive

  • non-dispersive

lens_mode: (recommended) NX_CHAR ⤆

projection: (recommended) NX_CHAR ⤆

angular_acceptance: (optional) NX_FLOAT ⤆

spatial_acceptance: (optional) NX_FLOAT ⤆

field_aperture: (optional) NXaperture ⤆

The size and position of the field aperture inserted in the column. To ...

The size and position of the field aperture inserted in the column. To add additional or other apertures use the APERTURE group of NXcollectioncolumn.

contrast_aperture: (optional) NXaperture ⤆

The size and position of the contrast aperture inserted in the column. ...

The size and position of the contrast aperture inserted in the column. To add additional or other apertures use the APERTURE group of NXcollectioncolumn.

iris: (optional) NXaperture ⤆

Size, position and shape of the iris inserted in the column. ...

Size, position and shape of the iris inserted in the column.

The iris is an aperture in the lens with a variable diameter which can reduce the number of electrons entering the analyzer.

To add additional or other slits use the APERTURE group of NXcollectioncolumn.

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

ENERGYDISPERSION: (required) NXenergydispersion ⤆

scheme: (required) NX_CHAR ⤆

Any of these values:

  • tof

  • hemispherical

  • double hemispherical

  • cylindrical mirror

  • display mirror

  • retarding grid

pass_energy: (recommended) NX_FLOAT {units=NX_ENERGY} ⤆

Only one of ``pass_energy`` or ``drift_energy`` should be supplied. `` ...

Only one of pass_energy or drift_energy should be supplied. pass_energy should be used when working with hemispherical analyzers.

drift_energy: (recommended) NX_FLOAT {units=NX_ENERGY} ⤆

Only one of ``pass_energy`` or ``drift_energy`` should be supplied. `` ...

Only one of pass_energy or drift_energy should be supplied. drift_energy should be used if a TOF is used in the energy dispersive part of the electron analyzer.

energy_scan_mode: (recommended) NX_CHAR ⤆

entrance_slit: (optional) NXaperture ⤆

Size, position and shape of the entrance slit in dispersive analyzers. ...

Size, position and shape of the entrance slit in dispersive analyzers.

To add additional or other slits use the APERTURE group of NXenergydispersion.

exit_slit: (optional) NXaperture ⤆

Size, position and shape of the exit slit in dispersive analyzers. ...

Size, position and shape of the exit slit in dispersive analyzers.

To add additional or other slits use the APERTURE group of NXenergydispersion.

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

ELECTRON_DETECTOR: (required) NXelectron_detector

amplifier_type: (recommended) NX_CHAR ⤆

Type of electron amplifier in the first amplification step. ...

Type of electron amplifier in the first amplification step.

Any of these values: MCP | channeltron

detector_type: (recommended) NX_CHAR ⤆

Description of the detector type. ...

Description of the detector type.

Any of these values:

  • DLD

  • Phosphor+CCD

  • Phosphor+CMOS

  • ECMOS

  • Anode

  • Multi-anode

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

raw_data: (recommended) NXdata

Contains the raw data collected by the detector before calibration. ...

Contains the raw data collected by the detector before calibration. The data which is considered raw might change from experiment to experiment due to hardware pre-processing of the data. This group ideally collects the data with the lowest level of processing possible.

Axes should be named according to the conventions defined below. Note that this list is a glossary with explicitly named axis names, which is only intended to cover the most common measurement axes and is therefore not complete. It is possible to add axes with other names at any time.

@signal: (required) NX_CHAR ⤆

Obligatory value: raw

raw: (required) NX_NUMBER ⤆

Raw data before calibration.

pixel_x: (optional) NX_NUMBER {units=NX_ANY}

Detector pixel in x direction.

pixel_y: (optional) NX_NUMBER {units=NX_ANY}

Detector pixel in y direction.

energy: (recommended) NX_NUMBER {units=NX_ENERGY}

(Un)calibrated energy axis.

@type: (required) NX_CHAR

The energy can be either stored as kinetic or as binding energy. ...

The energy can be either stored as kinetic or as binding energy.

Any of these values:

  • kinetic: (Un)calibrated kinetic energy axis. This concept is related to term 3.35 of the ISO 18115-1:2023 standard.

  • binding: (Un)calibrated binding energy axis. This concept is related to term 12.16 of the ISO 18115-1:2023 standard.

photon_energy: (optional) NX_NUMBER {units=NX_ENERGY}

(Un)calibrated photon energy of the incoming probe beam. ...

(Un)calibrated photon energy of the incoming probe beam.

Could be a link to /entry/instrument/beam_probe/incident_energy.

kx: (optional) NX_NUMBER {units=NX_WAVENUMBER}

(Un)calibrated k-space coordinate in x direction. It is envisioned t ...

(Un)calibrated k-space coordinate in x direction. It is envisioned that the axes in momentum space are named kx, ky, and kz. Typically, the vectors in momentum space are defined such that kx and ky comprise the parallel component, while kz is the perpendicular component.

It is also possible to define k_parallel and k_perpendicular for the parallel and perpendicular momenta, respectively.

Units are typically 1/angstrom.

ky: (optional) NX_NUMBER {units=NX_WAVENUMBER}

(Un)calibrated k-space coordinate in y direction. For more informati ...

(Un)calibrated k-space coordinate in y direction. For more information, see the definition of the kx axis.

kz: (optional) NX_NUMBER {units=NX_WAVENUMBER}

(Un)calibrated k-space coordinate in z direction. For more informati ...

(Un)calibrated k-space coordinate in z direction. For more information, see the definition of the kx axis.

k_parallel: (optional) NX_NUMBER {units=NX_WAVENUMBER}

(Un)calibrated parallel component in k-space. ...

(Un)calibrated parallel component in k-space.

k_parallel and k_perpendicular describe how the electron’s wave vector k is split into components relative to the surface.

k_parallel is the component of the electron’s wave vector that is parallel to the surface. It is conserved during the photoemission process. This means that the electron’s momentum along the surface inside the material is directly related to its measured momentum outside the material.

Units are typically 1/angstrom.

k_perpendicular: (optional) NX_NUMBER {units=NX_WAVENUMBER}

(Un)calibrated perpendicular component in k-space. ...

(Un)calibrated perpendicular component in k-space.

k_perpendicular is the component that is normal (perpendicular) to the surface. It is not conserved during photoemission because the electron experiences a potential change when it exits the material into vacuum. To determine k_perpendicular inside the material, one typically needs to estimate the inner potential \(V_0\), which accounts for the energy shift due to the material’s work function and electronic structure.

Units are typically 1/angstrom.

angular0: (optional) NX_NUMBER {units=NX_ANGLE}

First (un)calibrated angular coordinate. It is envisioned that the a ...

First (un)calibrated angular coordinate. It is envisioned that the axes in angular space are named angular0 and angular1.

The angular axes should be named in order of decreasing speed, i.e., angular0 should be the fastest scan axis and angular1 should be the slow-axis angular coordinate. However, angular0 may also be second slow axis if the measurement is angularly integrated and angular1 could also be the second fast axis in the case of simultaneous dispersion in two angular dimensions.

angular1: (optional) NX_NUMBER {units=NX_ANGLE}

Second (un)calibrated angular coordinate. ...

Second (un)calibrated angular coordinate.

For more information, see the definition of the angular0 axis.

This is typically the slower scan axis compared to angular0.

spatial0: (optional) NX_NUMBER {units=NX_LENGTH}

First (un)calibrated spatial coordinate. It is envisioned that the a ...

First (un)calibrated spatial coordinate. It is envisioned that the axes in angular space are named spatial0 and spatial1.

The spatial axes should be named in order of decreasing speed, i.e., spatial0 should be the fastest scan axis and spatial1` should be the slow-axis spatial coordinate. However, spatial may also be second slow axis if the measurement is spatially integrated and spatial1 could also be the second fast axis in the case of simultaneous dispersion in two spatial dimensions.

spatial1: (optional) NX_NUMBER {units=NX_LENGTH}

Second (un)calibrated spatial coordinate. ...

Second (un)calibrated spatial coordinate.

For more information, see the definition of the spatial0 axis.

This is typically the slower scan axis compared to spatial0.

delay: (optional) NX_NUMBER {units=NX_TIME} ⤆

(Un)calibrated delay time.

temperature: (optional) NX_NUMBER {units=NX_TIME}

(Un)calibrated temperature axis in case of experiments where the tem ...

(Un)calibrated temperature axis in case of experiments where the temperature was scanned. This is typically the sample temperature and could be linked from /entry/sample/temperature_env/temperature_sensor/value.

MANIPULATOR: (optional) NXmanipulator

Manipulator for positioning of the sample.

temperature_sensor: (recommended) NXsensor ⤆

name: (recommended) NX_CHAR ⤆

measurement: (required) NX_CHAR ⤆

Obligatory value: temperature

type: (optional) NX_CHAR ⤆

value: (required) NX_FLOAT ⤆

sample_heater: (optional) NXactuator ⤆

name: (recommended) NX_CHAR ⤆

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: temperature

type: (optional) NX_CHAR ⤆

heater_power: (required) NX_FLOAT ⤆

PID_CONTROLLER: (recommended) NXpid_controller ⤆

setpoint: (recommended) NX_FLOAT ⤆

cryostat: (optional) NXactuator ⤆

name: (recommended) NX_CHAR ⤆

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: temperature

type: (optional) NX_CHAR ⤆

PID_CONTROLLER: (required) NXpid_controller ⤆

setpoint: (recommended) NX_FLOAT ⤆

drain_current_amperemeter: (optional) NXsensor ⤆

name: (recommended) NX_CHAR ⤆

measurement: (required) NX_CHAR ⤆

Obligatory value: current

type: (optional) NX_CHAR ⤆

value: (required) NX_FLOAT ⤆

sample_bias_voltmeter: (recommended) NXsensor ⤆

name: (recommended) NX_CHAR ⤆

measurement: (required) NX_CHAR ⤆

Obligatory value: voltage

type: (optional) NX_CHAR ⤆

value: (required) NX_FLOAT ⤆

sample_bias_potentiostat: (recommended) NXactuator ⤆

name: (recommended) NX_CHAR ⤆

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: voltage

type: (optional) NX_CHAR ⤆

PID_CONTROLLER: (recommended) NXpid_controller ⤆

setpoint: (recommended) NX_FLOAT ⤆

device_information: (recommended) NXfabrication ⤆

vendor: (recommended) NX_CHAR ⤆

model: (recommended) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

pressure_gauge: (recommended) NXsensor ⤆

Device to measure the gas pressure in the instrument.

name: (recommended) NX_CHAR ⤆

measurement: (required) NX_CHAR ⤆

Obligatory value: pressure

type: (optional) NX_CHAR ⤆

value: (required) NX_FLOAT {units=NX_PRESSURE} ⤆

In case of a single or averaged gas pressure measurement, this is the sc ...

In case of a single or averaged gas pressure measurement, this is the scalar gas pressure. It can also be an 1D array of measured pressures (without time stamps).

value_log: (optional) NXlog ⤆

value: (required) NX_NUMBER {units=NX_PRESSURE} ⤆

In the case of an experiment in which the gas pressure changes and is ...

In the case of an experiment in which the gas pressure changes and is recorded, this is an array of length m of gas pressures.

flood_gun: (optional) NXactuator ⤆

Device to bring low-energy electrons to the sample for charge neutralization

name: (recommended) NX_CHAR ⤆

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: current

type: (optional) NX_CHAR ⤆

current: (recommended) NX_FLOAT {units=NX_CURRENT}

In case of a fixed or averaged electron current, this is the scalar curr ...

In case of a fixed or averaged electron current, this is the scalar current. It can also be an 1D array of output current (without time stamps).

current_log: (optional) NXlog

value: (required) NX_NUMBER {units=NX_CURRENT} ⤆

In the case of an experiment in which the electron current is changed ...

In the case of an experiment in which the electron current is changed and recorded with time stamps, this is an array of length m of current setpoints.

history: (optional) NXhistory ⤆

A set of activities that occurred to the instrument prior to/during the ph ...

A set of activities that occurred to the instrument prior to/during the photoemission experiment, including any activities performed on the individual instrument parts. This group can be used to describe the preparation of the instrument prior to the experiment, e.g. the cleaning procedure for a spin filter crystal.

energy_axis_calibration: (recommended) NXcalibration

Calibration event on the energy axis. ...

Calibration event on the energy axis.

For XPS, the calibration should ideally be performed according to ISO 15472:2010 specification.

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: energy

calibrated_axis: (required) NX_FLOAT {units=NX_ENERGY} ⤆

This is the calibrated energy axis to be used for data plotting.

AXIS_axis_calibration: (optional) NXcalibration

Calibration event for one of the axes in the ...

Calibration event for one of the axes in the NXdata.

The naming of these calibrations should follow those in the NXdata. For example, for the momentum axis kx, the corresponding calibration should be called kx_axis_calibration.

calibrated_axis: (recommended) NX_FLOAT ⤆

energy_referencing: (optional) NXcalibration

For energy referencing, the measured energies are corrected for the charging ...

For energy referencing, the measured energies are corrected for the charging potential (i.e., the electrical potential of the surface region of an insulating sample, caused by irradiation) such that those energies correspond to a sample with no surface charge. Usually, the energy axis is adjusted by shifting all energies uniformly until one well-defined emission line peak (or the Fermi edge) is located at a known _correct_ energy.

This concept is related to term 12.74 ff. of the ISO 18115-1:2023 standard.

physical_quantity: (required) NX_CHAR ⤆

Obligatory value: energy

level: (recommended) NX_CHAR

Electronic core or valence level that was used for the calibration. ...

Electronic core or valence level that was used for the calibration.

This should be single string defining the core or valence level that was used for energy referencing.

The notation should be the same as the one described in the NXmpes/ENTRY/transitions field.

reference_peak: (recommended) NX_CHAR

Reference peak that was used for the calibration. ...

Reference peak that was used for the calibration.

For example: adventitious carbon | C-C | metallic Au | elemental Si | Fermi edge | vacuum level

binding_energy: (recommended) NX_FLOAT {units=NX_ENERGY}

The binding energy (in units of eV) that the specified emission line appea ...

The binding energy (in units of eV) that the specified emission line appeared at, after adjusting the binding energy scale.

This concept is related to term 12.16 of the ISO 18115-1:2023 standard.

offset: (recommended) NX_FLOAT {units=NX_ENERGY} ⤆

Offset between measured binding energy and calibrated binding energy of th ...

Offset between measured binding energy and calibrated binding energy of the emission line.

calibrated_axis: (recommended) NX_FLOAT {units=NX_ENERGY} ⤆

This is the calibrated energy axis to be used for data plotting. ...

This is the calibrated energy axis to be used for data plotting.

This could be a link to /entry/data/energy.

transmission_correction: (optional) NXcalibration

In the transmission correction, each intensity measurement for electrons of ...

In the transmission correction, each intensity measurement for electrons of a given kinetic energy is multiplied by the corresponding value in the relative_intensity field of the transmission_function. This calibration procedure is used to account for energy-dependent transmission efficiencies in certain lens modes.

transmission_function: (recommended) NXdata ⤆

Transmission function of the electron analyzer. ...

Transmission function of the electron analyzer.

The transmission function (TF) specifies the detection efficiency for electrons of different kinetic energy passing through the electron analyzer.

This can be a link to /entry/instrument/electronanalyzer/transmission_function.

@signal: (required) NX_CHAR ⤆

Obligatory value: relative_intensity

@axes: (required) NX_CHAR ⤆

Obligatory value: kinetic_energy

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

Kinetic energy values

relative_intensity: (required) NX_FLOAT (Rank: 1, Dimensions: [n_transmission_function]) {units=NX_UNITLESS}

Relative transmission efficiency for the given kinetic energies

REGISTRATION: (optional) NXregistration

Describes the operations of image registration (i.e. affine transformations ...

Describes the operations of image registration (i.e. affine transformations like rotations or translations).

DISTORTION: (optional) NXdistortion

Describes the operations of image distortion correction.

CALIBRATION: (optional) NXcalibration

Any further calibration procedures. For example, a calibration event for the ...

Any further calibration procedures. For example, a calibration event for the photoemission counts (e.g., by dividing by some base line intensity \(I_0\).).

FIT: (optional) NXfit

Any fit procedures.

SAMPLE: (required) NXsample ⤆

name: (required) NX_CHAR ⤆

identifier: (recommended) NX_CHAR

chemical_formula: (recommended) NX_CHAR ⤆

atom_types: (recommended) NX_CHAR

List of comma-separated elements from the periodic table ...

List of comma-separated elements from the periodic table that are contained in the sample. If the sample substance has multiple components, all elements from each component must be included in atom_types.

physical_form: (recommended) NX_CHAR ⤆

situation: (recommended) NX_CHAR ⤆

Any of these values:

  • vacuum

  • inert atmosphere

  • oxidizing atmosphere

  • reducing atmosphere

history: (recommended) NXhistory ⤆

A set of activities that occurred to the sample prior to/during photoemiss ...

A set of activities that occurred to the sample prior to/during photoemission experiment.

sample_preparation: (recommended) NXactivity ⤆

Details about the sample preparation for the photoemission experiment (e ...

Details about the sample preparation for the photoemission experiment (e.g. UHV cleaving, in-situ growth, sputtering/annealing, etc.).

start_time: (required) NX_DATE_TIME ⤆

end_time: (recommended) NX_DATE_TIME ⤆

method: (recommended) NX_CHAR

Details about the method of sample preparation before the photoemissio ...

Details about the method of sample preparation before the photoemission experiment.

temperature_env: (recommended) NXenvironment ⤆

Sample temperature (either controlled or just measured) and actuators/sens ...

Sample temperature (either controlled or just measured) and actuators/sensors controlling/measuring it.

value: (optional) NX_FLOAT {units=NX_TEMPERATURE} ⤆

This is to be used if there is no actuator/sensor that controls/measures ...

This is to be used if there is no actuator/sensor that controls/measures the temperature.

An example would be a room temperature experiment where the temperature is not actively measured, but rather estimated.

Note that this method for recording the temperature is not advised, but using NXsensor and NXactuator is strongly recommended instead.

temperature_sensor: (recommended) NXsensor ⤆

Temperature sensor measuring the sample temperature. ...

Temperature sensor measuring the sample temperature.

In most cases, this can be a link to /entry/instrument/manipulator/temperature_sensor if a manipulator is present in the instrument.

sample_heater: (optional) NXactuator ⤆

Device to heat the sample. ...

Device to heat the sample.

In most cases, this can be a link to /entry/instrument/manipulator/sample_heater if a manipulator is present in the instrument.

cryostat: (optional) NXactuator ⤆

Cryostat for cooling the sample. ...

Cryostat for cooling the sample.

In most cases, this can be a link to /entry/instrument/manipulator/cryostat if a manipulator is present in the instrument.

gas_pressure_env: (recommended) NXenvironment ⤆

Gas pressure surrounding the sample and actuators/sensors controlling/meas ...

Gas pressure surrounding the sample and actuators/sensors controlling/measuring it.

value: (optional) NX_FLOAT {units=NX_PRESSURE} ⤆

This is to be used if there is no actuator/sensor that controls/measures ...

This is to be used if there is no actuator/sensor that controls/measures the gas pressure around the sample. An example would be a UHV experiment where the gas pressure is not monitored.

Note that this method for recording the gas pressure is not advised, but using NXsensor and NXactuator is strongly recommended instead.

pressure_gauge: (recommended) NXsensor ⤆

Gauge measuring the gas pressure. ...

Gauge measuring the gas pressure.

In most cases, this can be a link to /entry/instrument/pressure_gauge or to another NXsensor measuring gas pressure (typically, the gauge in closest proximity to the sample) if such a pressure gauge is present in the instrument.

bias_env: (recommended) NXenvironment ⤆

Bias of the sample with respect to analyzer ground and actuators/sensors ...

Bias of the sample with respect to analyzer ground and actuators/sensors controlling/measuring it.

This concept is related to term 8.41 of the ISO 18115-1:2023 standard.

value: (optional) NX_FLOAT {units=NX_VOLTAGE} ⤆

This is to be used if there is no actuator/sensor that controls/measures ...

This is to be used if there is no actuator/sensor that controls/measures the bias.

Note that this method for recording the bias is not advised, but using NXsensor and NXactuator is strongly recommended instead.

voltmeter: (recommended) NXsensor ⤆

Sensor measuring the applied voltage. ...

Sensor measuring the applied voltage.

In most cases, this can be a link to /entry/instrument/manipulator/sample_bias_voltmeter if a manipulator is present in the instrument.

potentiostat: (optional) NXactuator ⤆

Actuator applying a voltage to sample and sample holder. ...

Actuator applying a voltage to sample and sample holder.

In most cases, this can be a link to /entry/instrument/manipulator/sample_bias_potentiostat if a manipulator is present in the instrument.

drain_current_env: (optional) NXenvironment ⤆

Drain current of the sample and sample holder.

value: (optional) NX_FLOAT {units=NX_CURRENT} ⤆

This is to be used if there is no actuator/sensor that controls/measures ...

This is to be used if there is no actuator/sensor that controls/measures the drain current.

Note that this method for recording the drain current is not advised, but using NXsensor and NXactuator is strongly recommended instead.

amperemeter: (recommended) NXsensor ⤆

Amperemeter measuring the drain current of the sample and sample holder. ...

Amperemeter measuring the drain current of the sample and sample holder.

In most cases, this can be a link to /entry/instrument/manipulator/drain_current_amperemeter if a manipulator is present in the instrument.

flood_gun_current_env: (optional) NXenvironment ⤆

Current of low-energy electrons to the sample (for charge neutralization) ...

Current of low-energy electrons to the sample (for charge neutralization) and actuators/sensors controlling/measuring it.

flood_gun: (recommended) NXactuator ⤆

Flood gun creating a current of low-energy electrons. ...

Flood gun creating a current of low-energy electrons.

In most cases this can be a link to /entry/instrument/flood_gun if a flood_gun is present in the instrument.

value: (optional) NX_FLOAT {units=NX_CURRENT}

This is to be used if there is no actuator/sensor that controls/measur ...

This is to be used if there is no actuator/sensor that controls/measures the drain_current.

Note that this method for recording the flood gun current is not advised, but using NXsensor and NXactuator is strongly recommended instead.

data: (required) NXdata ⤆

The default NXdata group containing a view on the measured data. ...

The default NXdata group containing a view on the measured data. This NXdata group contains a collection of the main relevant fields (axes). If you want to provide additional views on your data, you can additionally use the generic NXdata group of NXentry.

In NXmpes, it is recommended to provide an energy axis.

Axes should be named according to the conventions defined below. Note that this list is a glossary with explicitly named axis names, which is only intended to cover the most common measurement axes and is therefore not complete. It is possible to add axes with other names at any time.

@signal: (required) NX_CHAR ⤆

Obligatory value: data

@energy_indices: (recommended) NX_INT ⤆

data: (required) NX_NUMBER {units=NX_ANY} ⤆

Represents a measure of one- or more-dimensional photoemission counts, whe ...

Represents a measure of one- or more-dimensional photoemission counts, where the varied axis may be for example energy, momentum, spatial coordinate, pump-probe delay, spin index, temperature, etc. The axes traces should be linked to the actual encoder position in NXinstrument or calibrated axes in NXprocess.

energy: (recommended) NX_NUMBER {units=NX_ENERGY}

Calibrated axis for the energy of the measured electrons. ...

Calibrated axis for the energy of the measured electrons.

Could be linked from the respective ‘@reference’ field.

@type: (required) NX_CHAR

The energy can be either stored as kinetic or as binding energy. ...

The energy can be either stored as kinetic or as binding energy.

Any of these values:

  • kinetic: Calibrated kinetic energy axis. In case the kinetic energy axis is referenced to the Fermi level \(E_F\) (e.g., in entry/process/energy_referencing), kinetic energies \(E\) are provided as \(E-E_F\). This concept is related to term 3.35 of the ISO 18115-1:2023 standard.

  • binding: Calibrated binding energy axis. This concept is related to term 12.16 of the ISO 18115-1:2023 standard.

@reference: (recommended) NX_CHAR

The energy can be dispersed according to different strategies. ``@refere ...

The energy can be dispersed according to different strategies. @reference points to the path of a field defining the calibrated axis which the energy axis refers.

For example:

@reference: ‘entry/process/energy_calibration/calibrated_axis’

photon_energy: (optional) NX_NUMBER {units=NX_ENERGY}

Calibrated photon energy of the incoming probe beam. ...

Calibrated photon energy of the incoming probe beam.

Could be a link to /entry/instrument/beam_probe/incident_energy.

kx: (optional) NX_NUMBER {units=NX_WAVENUMBER}

Calibrated k-space coordinate in x direction. It is envisioned that the ax ...

Calibrated k-space coordinate in x direction. It is envisioned that the axes in momentum space are named kx, ky, and kz. Typically, the vectors in momentum space are defined such that kx and ky comprise the parallel component, while kz is the perpendicular component.

It is also possible to define k_parallel and k_perp for the parallel and perpendicular momenta, respectively.

Units are typically 1/angstrom.

ky: (optional) NX_NUMBER {units=NX_WAVENUMBER}

Calibrated k-space coordinate in y direction. For more information, see th ...

Calibrated k-space coordinate in y direction. For more information, see the definition of the kx axis.

kz: (optional) NX_NUMBER {units=NX_WAVENUMBER}

Calibrated k-space coordinate in z direction. For more information, see th ...

Calibrated k-space coordinate in z direction. For more information, see the definition of the kx axis.

k_parallel: (optional) NX_NUMBER {units=NX_WAVENUMBER}

Calibrated parallel component in k-space. ...

Calibrated parallel component in k-space.

k_parallel and k_perpendicular describe how the electron’s wave vector k is split into components relative to the surface.

k_parallel is the component of the electron’s wave vector that is parallel to the surface. It is conserved during the photoemission process. This means that the electron’s momentum along the surface inside the material is directly related to its measured momentum outside the material.

Units are typically 1/angstrom.

k_perpendicular: (optional) NX_NUMBER {units=NX_WAVENUMBER}

Calibrated perpendicular component in k-space. ...

Calibrated perpendicular component in k-space.

k_perpendicular is the component that is normal (perpendicular) to the surface. It is not conserved during photoemission because the electron experiences a potential change when it exits the material into vacuum. To determine k_perpendicular inside the material, one typically needs to estimate the inner potential \(V_0\), which accounts for the energy shift due to the material’s work function and electronic structure.

Units are typically 1/angstrom.

angular0: (optional) NX_NUMBER {units=NX_ANGLE}

First calibrated angular coordinate. It is envisioned that the axes in ang ...

First calibrated angular coordinate. It is envisioned that the axes in angular space are named angular0 and angular1.

The angular axes should be named in order of decreasing speed, i.e., angular0 should be the fastest scan axis and angular1 should be the slow-axis angular coordinate. However, angular0 may also be second slow axis if the measurement is angularly integrated and angular1 could also be the second fast axis in the case of simultaneous dispersion in two angular dimensions.

angular1: (optional) NX_NUMBER {units=NX_ANGLE}

Second calibrated angular coordinate. ...

Second calibrated angular coordinate.

For more information, see the definition of the angular0 axis.

This is typically the slower scan axis compared to angular0.

spatial0: (optional) NX_NUMBER {units=NX_LENGTH}

First calibrated spatial coordinate. It is envisioned that the axes in ang ...

First calibrated spatial coordinate. It is envisioned that the axes in angular space are named spatial0 and spatial1.

The spatial axes should be named in order of decreasing speed, i.e., spatial0 should be the fastest scan axis and spatial1` should be the slow-axis spatial coordinate. However, spatial may also be second slow axis if the measurement is spatially integrated and spatial1 could also be the second fast axis in the case of simultaneous dispersion in two spatial dimensions.

spatial1: (optional) NX_NUMBER {units=NX_LENGTH}

Second calibrated spatial coordinate. ...

Second calibrated spatial coordinate.

For more information, see the definition of the spatial0 axis.

This is typically the slower scan axis compared to spatial0.

delay: (optional) NX_NUMBER {units=NX_TIME} ⤆

Calibrated pump-probe delay time. Could be a link to ...

Calibrated pump-probe delay time. Could be a link to /entry/instrument/beam_pump/pulse_delay.

temperature: (optional) NX_NUMBER {units=NX_TIME}

Calibrated temperature axis in case of experiments where the temperature w ...

Calibrated temperature axis in case of experiments where the temperature was scanned. This is typically the sample temperature and could be linked from /entry/sample/temperature_env/temperature_sensor/value.

Hypertext Anchors

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

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXmpes.nxdl.xml