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As part of a "Wright Center for
Innovation," SCSAM has installed a dual
beam FIB (focused ion beam) system of the
type xT Nova Nanolab 200 (FEI). In addition
to the focused ion beam, which is used for
machining thin foils suitable for TEM
directly out of the specimen surface, this
instrument includes a complete and
very-high-quality scanning electron
microscope. This system has the advantage
that the specimen can be observed by
(high-resolution) SEM while being milled by
the ion beam. Compared to previous FEI FIB
systems, the Nova comes with a newly
designed computer interface and software
that enables entirely automated milling.
Moreover, the Nova includes a newly
designed internal "lift-out-" system for
transferring the thin film generated by
ion-beam milling onto a special kind of Cu
support grid, which can then be loaded into
the specimen holder of a TEM.
For elemental analysis, the system is
equipped with a state-of-the-art XEDS
XFlash detector 4010 system by Bruker. At
the heart of it the system contains a
Si-drifted detector, which has been
specially selected to provide an
outstanding energy resolution with a FWHM
(full width at half maximum) of
125 eV for Mn Kα
(5.899 keV) at a throughputs of
60..90 kcps (kilo counts per
second). This detector is also suited for
the detection of light elements. At its
highest throughput the system is capable of
counting up to 275 kcps.
Due to the special chip design with
integrated charge amplifier, the XFlash can
process extremely high count rates and at
the same time displays a very good energy
resolution, unrivalled by any other energy
dispersive X-ray detectors. This is due to
a monolithically integrated on-chip FET
acting as a signal amplifier and supports
unprecedented energy resolution. The
detector has an active area of
10 mm2 and is cooled by a
Peltier element. It has a super light
element window (SLEW), allowing the
detection of boron and heavier
elements.
A state-of-the-art Nordlys II EBSD
Detector serves for EBSD (electron
backscatter diffraction) and related
techniques. EBSD measurements of phase and
orientation rely on detecting and analyzing
electron backscatter (Kikuchi) patterns
(EBSP) generated in the SEM from a
polycrystalline sample. NordlysS achieves
the high sensitivity and CCD resolution. At
its highest resolution setting, the full
1344 × 1024 × 12
bit pixel CCD array is used to digitize
EBSP's offering a direct benefit for phase
identification and discrimination of
materials with very similar
crystallographic lattice parameters as well
as accurate measurement of orientation in
materials with close c/a
ratios, where pseudo?symmetry can thwart
accurate orientation measurements.
Combining NordlysS and Advanced Fit
software enables reliable determination of
orientations down to 0.5° and correct
identification of orientations in
pseudo-symmetric materials with
c/a ratios as low as
2 %.
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