Electron tomographic resolution of microns-thick specimens in the ultrahigh voltage electron microscope

• The electron tomography resolution for microns-thick specimens is determined by experiment in the ultra-high voltage electron microscope.
• The electron tomography resolution is evaluated using the Fourier shell correlation method.
• The limitations of electron tomography for microns-thick specimens are due largely to the image quality degradation at higher tilt angle range.

In this study, we determine the electron tomography (ET) resolution for microns-thick specimens by experiment in the ultra-high voltage electron microscope. A tilt series of projection images of a tilted 8 μm thick epoxy-resin film are first acquired. Tomographic reconstructions are then calculated and the resolution is evaluated with the Fourier shell correlation method. The ET resolution of 32 nm is achieved under the condition of 2 MV accelerating voltage. We also demonstrate that some high tilt angle projections may be little useful for improving the final ET resolution because of the corresponding poor image qualities. These results are helpful to understand the possibility and limitation of ET applications in microns-thick specimens.