Zeiss Crossbeam 550, Instruction Manual

Page: 88 / 136

6 Operation | 6.5 Finding Appropriate Detector Settings ZEISS
6.5.7 Setting up the aSTEM/STEM Detector
Purpose The aSTEM/STEM detector is used for compositional imaging or topographical imaging of ultra-
thin specimens. The aSTEM/STEM detector is available either with one video output channel
(aSTEM1) or with four video output channels (aSTEM4). The aSTEM detector is optionally avail-
able.
The aSTEM/STEM detector is equipped with several separate diode segments. The signals of the
segments can individually be added to or subtracted from the output signal in order to allow dif-
ferent STEM imaging modes, e.g. bright field (BF) or oriented dark field (ODF). The most com-
monly used STEM imaging modes are predefined and can be selected from a drop-down menu in
the STEM Control panel.
Fig. 35: Asbestos, oriented darkfield (ODF) image captured with an aSTEM 4 detector (left), ODF
image showing real information about bending and lattice defects within each fiber (right).
STEM Control STEM imaging
mode Output signal
BF S1
DF S2 + S3
ODF S2 - S3
ODF90° S3 - S2
ODF + BF S1 + S2 - S3
ODF90° + BF S1 - S2 + S3
BF + DF All on
User defined name Custom combination
of segments
Active segments
with +/- signs Custom combination
of segments.
"+" on, "-" inverted
88 Instruction Manual ZEISS Crossbeam 550L, Crossbeam 550 | en-US | Rev. 3 | 349500-8122-000