Chromatic Correction within the TEAM project
The TEAM (Transmission Electron Aberration-corrected Microscope) project, a research project for the development of a new generation of high-end electron microscopes, had selected CEOS for the development of a spherical and chromatic aberration corrector.
CEOS's previous TEM correctors could correct for spherical aberration only. The logically next step was the correction of chromatic aberration as well, as it had already been done in SEM. Cc-correction had been considered an extremely challenging technological task. The stability requirements for the supplies in the sub 0.1 ppm range, the complicated electron optics involved and the required machining precision require research at the very front of technology and theory.
The Cc-corrector uses the electric-magnetic quadrupole-octupole principle like the CEOS SEM corrector. But its setup is much more elaborate due to the large number of additional aberrations, which have to be controlled. The number of critical aberrations increases drastically, if a resolution limit of 0.05 nm is aimed for while retaining a sufficiently large field of view.
All TEAM microscopes are running: 0.05 nm details resolved!
Within the TEAM project CEOS delivered various correctors, which have meanwhile been installed into three microscopes. All microscopes are now running in their final target laboratories in the USA.
- The first chromatic corrector was installed in a Titan microscope at the Argonne National Laboratory.
- The so-called TEAM0.5 microscope housing CEOS's improved Cs correctors for TEM and STEM is running at the Lawrence Berkeley National Laboratory(LBNL). With this instrument a first milestone could be reached: 0.05 nm details have been resolved in TEM and STEM imaging.
- TEAM1, the microscope, which combines all new features of the TEAM project has been installed at the LBNL. It was officially set in operation for the users at the National Center for Electron Microscopy in October. It has already produced scientific results, which will be published in the near future.
All these machines will continuously produce new scientific data. We will keep you informed about them, as soon as they are published, on this page and in our literature list.
Other applications of chromatic correction
Besides the hunt for highest resolution in EM a second class of applications of Cc-correction uses instruments which require large pole piece distances in the objective lens. This includes
- in-situ microscopy
- applications requiring high tilt angles like tomography
- magnetic field free imaging
For such applications resolutions in the 0.1 nm range become possible even with pole gaps of 1 cm.