Dear EBSD friends,
I am wondering what the possibilities are for EBSD without sample tilt.
I vaguely remember a paper (or conference talk) where this was done. I think they used a detector which was "penetrated" by the SEM beam, such that the EBSD pattern could be captured directly above the non-tilted sample.
Can anyone point me in the right direction for this, or suggest literature where something like this is done?
Many thanks!
Hi, I think thermo fisher is testing this (authors affiliations)
Article Tilt-free EBSD
i think No.. its not possible to resolve the Kikuchi patterns without tilting
The collection of EBSD patterns is not linked to a sample tilt. The applied tilt only increases the amount of backscattered electrons. The more problematic qustion is how to collect those patterns with a high angular solution and a small distance between pole piece and sample. The standatd configuration of a detector from the side combined with a sample highly tilted is the present solution.
Gert Nolze Thanks Gert.
- Why is the difference from pole piece to sample (i.e. WD) important? I know most SEMs are configured to work best at 5-10mm working distance (WD), and I understand that the stability of the beam and thus the resolution can deteriorate when larger WD is used, but the spatial resolution of EBSD is anyways limited to a few tens of nanometer so this shouldn't be an issue
- The reason why I am searching for 'tilt-free EBSD' is to find a way to avoid band asymmetry, i.e. excess-deficiency effects, in the patterns
Tijmen Vermeij in the paper I sent link before they show patterns with excess-deficiency without tilting and in other papers on-axis TKD and Kikuchi diffraction in TEM also have these effects without tilting. I'm not sure if it is possible to avoid it.
I couldn’t imagine how backscattered electrons could be detected without tilting.
Ebsd patterns are always formed, independent from any tilt. The problem is, that they are weak, and you need a detector at this position. Using the common installation from the side you need to move the sample so deep that the surface is below the detector. Than you can register the signal. However, it requires 10 to 100 times longer acquisition time. For a detector below the pole piece it is not that terrible, but the signal is still weak since the majority of the BSE disappears in the sample or lost so much energy that it only contributes to the background. With more sensitive detectors it will be able to map in future samples without tilt.
Here you go. This was our paper on that:
Article Nanostructure characterisation of flow-formed Cr–Mo–V steel ...
it is transmitted beam KDT
Soran
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