B2/B3: Photoemission & core-level spectroscopy¶
Introduction¶
Set of data storage objects to describe photoemission experiments including x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), hard x-ray photoelectron spectroscopy (HAXPES), angle-resolved photoemission spectroscopy (ARPES), two-photon photoemission (2PPE) and photoemission electron microscopy (PEEM). We also included descriptors for advanced specializations, such as spin-resolution, time resolution, near-ambient pressure conditions, dichroism etc.
New Application Definitions¶
We created two new application definitions:
- NXmpes:
A general appdef with minimalistic metadata requirements, apt to describe all photemission experiments.
New Base Classes¶
We developed entirely new base classes:
- NXelectronanalyser:
A base class to describe electron kinetic energy analizers. Contains the collective characteristics of the instrument such as energy resolution, and includes the following subclasses:
- NXcollectioncolumn:
Base class to describe the set of electronic lenses in the electron collection column (standard, PEEM, momentum-microscope, etc.).
- NXenergydispersion:
Base class to describe the energy dispersion sytem (hemispherical, time-of-flight, etc.).
- NXspindispersion:
Base class to describe the set of electronic lenses in the electron collection column.
- NXmanipulator:
A base class to describe the complex manipulators used in photoemission experiments, often with > 4 degrees of freedom, cryogenic cooling and other advanced features.
We developed three base classes to describe data processing, which can be used as subclasses of NXprocess if describing post-processing or as subclasses of NXdetector if describing live, electronics level processing:
- NXcalibration:
A base class to describe the 1D calibration of an axis, with a function mapping a raw data scale to a calibrated scale with the same number of points.
- NXdistortion:
A base class to describe the 2D distortion correction of an axis, with a matrix mapping a raw data image to a undistorted image.
- NXregistration:
A base class to describe the rigid transformations that are applied to an image. May be redundant as they can be described with NXtransformations.
New Common Base Classes¶
We developed two classes that are common to other techniques:
- NXlens_em:
A class to describe all types of lenses. Includes electrostatic lenses for electron energy analysers.
- NXdeflector
A class to describe all kinds of deflectors, including electrostatic and magnetostatic deflectors for electron energy analysers.
Base Classes Extended in Application Definitions¶
We use existent base classes in application definitions and add descriptors:
- NXaperture
Added fileds to describe analyser apertures and slits.
- NXbeam
Adedd fields to describe utrafast laser beams.
- NXdetector
Added fields to describe electron detectors (MCP+Phospor screen, delay lines etc.).
- NXentry
Added fields to describe an experiment.
- NXprocess
Added subclasses and collective processing descriptors.
- NXsample
Added descriptors specific to photoemission experiments.
- NXsource
Added descriptors for laboratory sources (X-ray, UV lamps) but mostly for ultrafast lasers with complex time structures.
- NXinstrument
Added descriptors for the overall resolutions of the experiment (energy, momentum, angular, spatial, temporal).
