ISO 23420-2021 pdf download.Microbeam analysis一Analytical electron microscopy一Method for the determination of energy resolution for electron energy loss spectrum analysis.
7.2.1 Obtain graphite and the other reference sample
Obtain a graphite and a second reference sample. The graphite reference sample has a Carbon K-edge and an EEL peak ECZLP in an EEL spectrum. The second reference sample should have an EEL peak ECZLp appearing close to the zero-loss peak, but the peak spread should not overlap with the zero-loss peak. For example, the boron nitride plasmon-loss (n – n) peak is suitable for the ECZLP as good as the graphite plasmon-loss (it + a) peak.
7.2.2 Measure Cis of graphite by using the XPS
Measure the carbon K-shell binding energy of the graphite using XPS. The Cis Es used as carbon K edge energy ECK of graphite of the EELS. The XPS shall be calibrated by ISO 15472:2010.
7.3 Setup of the S/TEM and the EELS, and sample setting
Samples are recommended to be drop-cast onto a TEM grid, e.g. a holey carbon film support grid, to
ease the measurement. The electron microscope should be adjusted for S/TEM observation in advance.
EELS should also be adjusted in advance so that EEL spectra can be easily obtained. Parameters of the
S/TEM and the EELS are recorded as described in 7,fi.
The quality of an EEL spectrum is easily affected by electron beam induced carbon contamination. The use of an anti-contamination device is strongly recommended for suppression of the contamination. Additionally, a clean environment in the column is also needed to minimise the contamination.
7.4 First energy step, öE1, calibration
7.4.1 EELS acquisition set-up
Set the EEL spectrometer acquisition time and integration numbers so as to secure a sufficient signal-to-noise ratio without any peak saturation for all measurements, including measurements in subsequent sections. Since the measurement conditions such as irradiation current, entrance aperture diameter and capturing device characterization like CCD / CMOS camera are different, acquisition time and integration number cannot be uniformized. Therefore, users of this procedure should optimise acquisition time and integration number for their own systems and should record these values.
7.4.2 Determining the EELS first energy step. 8E1
Set the energy step 6E1 to cover all range from the zero-loss peak to the carbon K edge Ec. of graphite.
In the parallel detection system, energy step SE1 is selected from the preset value under the condition as Formula (2).ISO 23420 pdf download.