[3dem] reflections from gold fiducials
Schmid, Michael F.
m-schmid at slac.stanford.edu
Mon Nov 6 13:57:01 PST 2017
We have seen these before; they are a nuisance. Sometimes they weaken the image of the gold fiducial or otherwise confuse the tracking. Crystalline ice chunks do this too, of course, usually much worse.
On 11/6/17, 1:13 PM, "3dem on behalf of Lars-Anders Carlson" <3dem-bounces at ncmir.ucsd.edu on behalf of lars-anders.carlson at umu.se> wrote:
Dear community,
We encountered something during tilt series acquisition recently that I
hadn't seen before: several 10 nm gold fiducials gave clear reflections,
see attached image (compressed snapshot - it looks stronger in the
original images).
The reflections were often symmetrically arranged around a fiducial and
would then disappear at the next tilt ange. We used a 100 um objective
aperture at a Krios at 300kV. Admittedly I never worried about the
crystalline arrangement of gold fiducials before, so I took some higher
mag images of the fiducials, and some of them look mosaic, others more
monocrystalline (see image), which could explain why some cause more
reflections than others.
Is this something people have encountered before? Are some batches of
fiducials better ordered than others at the atomic level? I'm curious to
hear what people think of this since it fascinated me...
Cheers,
Lars
--
Lars-Anders Carlson
Assistant Professor
Dept of Medical Biochemistry and Biophysics
Wallenberg Centre for Molecular Medicine
Umeå University
901 87 Umeå, Sweden
lab website including OPEN POSITIONS:
http://www.carlsonlab.se/
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