JEOL JSM-6390 LA, Руководство пользователя

Страница: 39 / 68

SEM manual ETHZ v1.4
35
J) Quantitative (or qualitative) EDS analysis
In the following, it is assumed that…
•
The “Thermo NSS” program is running.
•
You have created an NSS project folder or opened an existing one (see Section H.1 ).
EDS acquisition can be considered as “qualitative” (i.e., just checking the presence or
absence of some major to minor elements), or “quantitative” (providing you consider a
standard-based quantification, which is what we do in our lab). The following assumes your
goal is to get
standard-based quantitative analysis:
•
“Spectrum”: acquire a single EDX spectrum of the currently scanned area.
•
“Point & Shoot”: acquire an image and select point(s) or area(s) to be analysed by
EDS in this image. This is most likely what you need…
WARNING: If your goal is to perform quantitative analyses, you MUST…
(1) Always load the project template “Silicate calibrated analysis” if you want to run
quantitative analyses (see Section H.1 )! If you haven’t set this template when creating a
new NSS project, click again on the “Project Explorer” , select “silicate calibrated
analysis”, press the “Reset” button aside, and confirm.
(2) Ensure that you have set the Working Distance (WD) to 10 mm . If this is correct,
Thermo NSS will indicate in the footnotes WD 9.700 (at 15 keV) or 9.800 (at 20 keV) .
Figure 22. SEM & EDS information found at the footnote of the NSS program: acceleration
voltage (ACC), magnification (MAG), working distance (WD), last beam current
measurement (BC), dead time (DT), stored count rate (SR), and stage position (X, Y).
J.1) Load standard data
If your goal is to obtain accurate quantitative data , you must load the appropriate standard
data to obtain standard-based quantitative analysis (see also Fig. 23 ):
•
Select the tab “Standards” on the bottom-right panel.
•
Click on “Add Standards”; a new window opens:
o
The top frame displays all currently available standard calibrations.
o
The bottom frame lists the currently selected standards for your analysis.
o
ADD a standard, OPTION 1: Load a set of standards by clicking the button
“Load” and selecting the appropriate set of standards (based on your type of
analysis); choose the most recent one! This is the fastest way to get an initial
collection of standards. Once loaded, you can always remove or add another
standard (see OPTION 2 and REMOVE).
o
ADD a standard, OPTION 2: Select individual entries in the top list and click
“Add Selected”. This option might be necessary for special analyses, or to add
extra elements that were not loaded with OPTION 1.
o
REMOVE a standard: Select an entry in the bottom list and click “Remove
Selected” to remove a standard from your run. NEVER click “DELETE
SELECTED” as it will erase the standardisation file!