Block face SEM breakthrough

Monday, November 13, 2017 - 14:00
Focal Charge Compensation promises to expand versatility and increase data quality without prolonging acquisition times.
The technology is also said to enable easy imaging of even the most charge-prone samples.
Resin-embedded tissues and cells can be imaged without charging artifacts, while the pixel dwell time is reduced.
Decreasing beam exposure time not only ensures fast acquisition rates, but also guards against sample damage, which is key to acquiring reliable and reproducible 3D data.
Charging effects are clearly visible under high vacuum, in contrast to images taken with Focal Charge Compensation, which show no charging effects even in large expanses of bare resin. The images show a ~300 micron diameter axon bundle at different magnifications. [NCMIR]
As Professor Mark Ellisman, Director of NCMIR, says: “Focal Charge Compensation will breathe new life into block face scanning electron microscopy by allowing high quality imaging of previously intractable specimens, including legacy samples prepared with traditional electron microscopy stains.” 
This extension of the 3View system from Gatan eliminates specimen charging.
A gas injection system consisting of a tiny capillary needle is precisely located above the sample. 
Nitrogen is guided through this needle directly onto the block face surface while the chamber is maintained under high vacuum.
This eliminates charging without degrading image quality.
The needle retracts automatically during the cutting cycle so the workflow is uninterrupted and high acquisition rates are maintained.
The 3View system consists of an ultramicrotome directly integrated into the vacuum chamber of the Zeiss Sigma and GeminiSEM field emission scanning electron microscopes.
It enables automated serial block face imaging of embedded samples - such as cells or tissue - with a slice thickness down to 15 nm.
The sample is continuously cut and imaged, and a three-dimensional rendering of the sample with nanometre-scale resolution can be reconstructed.
Learn more here.
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