JEOL JSM-6390 LA, Руководство пользователя

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SEM manual ETHZ v1.4
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I.3) Tips on image acquisition time & magnification
•
Always use aperture 2
(or 1)
when acquiring images.
•
You can try to increase/decrease the current and adjust the counting time. A medium
current is recommended for most applications (spotsize 70-80) as it gives a strong
signal and a decent sub-micron imaging resolution . However:
o
A lower current (spotsize 50-70) will yield a weaker signal ( è longer imaging
time required) and provide a higher spatial resolution (< 1 µm).
o
A higher current (spotsize >80) will significantly increase the signal but will
yield a lower spatial resolution (large beam size) and is NOT recommended
for imaging .
o
NOTE: If a super-high spatial resolution in SE mode is required (e.g., for imaging foraminifera,
small 3D-image of crystal), use a higher voltage (20 or 25 keV) and the beam aperture 1!
•
Prefer a medium to high magnification (> 100x) to avoid problems of barrel effect on
the edges or shadow effect from the BSE or CL detector.
•
For mosaic images, select a magnification sufficient to reveal all the feature in each
individual image (i.e., consider the true pixel size in micrometre). Check the
Appendix A4 for determining the pixel size of your individual image of the mosaic.
Do not choose a too high magnification that would require to acquire way too many
images! For instance, a magnification between ~70 and 150x is commonly used for
a mosaic image of a full thin section with large grains (> 50-100 µm), but a higher
magnification would be required to reveal micron-sized phases in smaller areas.
I.4) Exporting your images
Images are stored immediately when the acquisition is over. However, you will still need to
export individual images to ultimately have an image with a scale bar (and with the point
you analysed in “Point & Shoot” shown on the image [see Section J.3 ]):
•
Select the image (or Point & Shoot) to export.
•
Click on menu “File > Export as FullRes TIF…”.
•
Click anywhere in the list of the acquired images. A new file ending with “…24bit.tif”
will appear. NOTE: This image is not readable in Thermo NSS; a grey image will
appear if you select it, that’s “normal”.
For mosaic images , you will first need to MERGE all the files by selecting the menu “Batch
Processing > Create Montage”. Export then the resulting merged image as a full resolution
TIF image (menu “File > Export as FullRes TIF…” as described above).