The Helios is a state of the art SEM, equipped with a field emission gun and a focused ion beam, combining the very fine milling capabilities used in the semiconductor industry with the superb imaging of the FEI scanning electron microscopes. While it is possible to produce high quality tomograms using the TEM's at the NYSBC, the Helios offers the advantage of doing the same for bulkier specimens, by iteratively imaging the surface of the specimen after removing a layer of specimen. These tomograms have the further advantage of not being subject to missing wedge or CTF artifacts, although the nominal resolution achievable is lower than with a TEM. In addition, this instrument adds the ability to produce electron transparent specimens for cryo-tomography.

A computer associated with this microscope has also been acquired. This computer runs under Windows XP and has a customized version of AMIRA, making the assembly of images produced by the Helios into 3-D maps a seamless process which can be easily followed by segmentation and other powerful capabilities for data visualization.

Specifications for this instrument, as well as operational specifics will be available to affiliates of the NYSBC at http://www.nysbc.net/twiki/bin/view/Main/CryoEM