Cryo-Transmission Electron Microscopy

Electron and ion beam technologies (Structural & Morphology Characterization)

The neutron instrumentation at the MLZ, in particular Small Angle Neutron Scattering, reflectometry and macromolecular crystallography allow to investigate structures in the range from 1 nm up to several hundred nm in reciprocal space. In soft matter and biology the contrast between hydrogen and deuterium is used to gain deep and quantitative insights about the shape and interactions of the objects forming the investigated structure.

Cryogenic Transmission electron microscopy (Cryo-TEM) yield real space pictures of soft matter systems; virtually it may complete and enhance any SANS investigation in reciprocal space on soft matter investigation in the range from 1 nm up to several hundred nm.

With Cryo-TEM, we are able to extract information in the real space about size measurements and distribution of particles, shape, self-assembly systems and aggregates. Transmission electron microscope allows to get quantitative information about roughness and intermolecular distances can be extracted and indirect information concerning average radius and periodical distances by performing a Fourier transform in TEM image. Additionally, diffraction patterns can be obtained.

With TEM, the energy filter and the energy loss method allows to get information about atomic composition of the observed system. The energy filter is an additional way to enhance contrast in complementary to thickness dependent amplitude contrast, the small angle phase contrast and the diffraction contrast for crystalline structure investigation.

The instrument is a 200 kV JEM-FS2200 from JEOL with a field emission gun (FEG) and an on-line Omega Energy Filter allowing measurements at magnification from x 50 to x 1 M with a resolution of 0,2 nm in point and 0,1 nm in lattice. The Microscope is equipped with a Tietz CMOS camera with 2048 x 2048 pixels square area. 

The soft matter samples have to be investigated either in dried or frozen state (Cryo-TEM) to be able to work in the necessary vacuum and to suppress blurring motion of the object as well as radiation damage.

As the samples have to be very thin (max~100nm), Cryo-TEM investigations require sophisticated sample preparation, the TEM laboratory comprises therfore an extended suite of preparation equipment. Users will be supported by JCNS scientists (M.S. Appavou) to conduct the suitable preparation and Cryo-TEM investigation. 

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