ISO 23420:2021 pdf free download – Microbeam analysis一Analytical electron microscopy一Method for the determination of energy resolution for electron energy loss spectrum analysis.
In order to understand the chemical composition, the atomic bonding and the electronic structure, electron energy loss analysis is often performed with the scanning transmission electron microscope or the transmission electron microscope (S/TEM) equipped with the electron energy loss (EEL) spectrometer.
In the analysis using EEL spectrometer system, the energy loss of incident electrons by the inelastic interaction via phonon and plasmon excitations, intra- and inter-band transitions and the inner shell ionization can be measured. The inner shell ionization is particularly useful and important as it gives the information on chemical composition of materials. For the precise analysis based on the energy loss peak decomposition and its energy shifts, it is vitally important to understand the energy resolution of the EEL spectrometer system. However, the determination method of the energy resolution is not standardized yet.
This document provides the procedures for energy step calibration and energy resolution determination useful for the electron energy loss spectrum analysis in the S/TEM equipped with the EEL spectrometer.
3.7
electron energy loss
energy shift of the electron kinetic energy due to the inelastic scattering in solids
3.8
energy dispersion
degree of change in position of the dispersed electrons at the detection plane (3k) per unit energy change
3.9
energy resolution
FWHM of the zero-loss (3.21) peak
3.10
energy step
energy selecting window (3.11) per channel (1) in the parallel detection (3.17) EELS, or energy range limited by the width of energy selecting slit in the serial detection (3.20) EELS
3.11
energy selecting window
energy range for selection of a specific energy loss value
3.12
entrance aperture
aperture for limiting the collection angle (3A) of the EEL spectrometer
3.13
geometric factor
ratio of distance from a projector lens to an EELS entrance aperture to distance from the projector lens to an image detection device
3.14
in-column type EELS
EELS system with the EEL spectrometer located in the imaging system of the TEM
3.15
irradiation diameter
diameter of the electron beam irradiation region for the TEM observation
3.16
K edge
energy loss related to K shell electron transition to the lowest empty state
3.17
parallel detection
simultaneous EELS signal detection for all energy-dispersed electrons focused on the detection plane (3k)
3.18
plasmon-loss
energy loss of electron due to excitation of the quantized plasma oscillations of electrons
3.19
post-column type EELS
EELS system with the EEL spectrometer located behind the imaging/detecting system of the TEM
3.20
serial detection
EEL spectrum detection by scanning the dispersed electrons across the energy selecting slit in front of the detector.