EM History at the Department
Electron microscopy as a research tool was introduced at the Department in connection with the moving into the Arrhenius Laboratory in 1973. Two TEM instruments were then acquired, a Siemens ELMISKOP 102 (point-to-point resolution 3.5 Å) and a Philips EM 301 with lower resolution but equipped with a Link EDS thin-window detector and a microanalysis system. The Siemens microscope was designed and used mainly for ‘high resolution’ work while the Philips instrument was intended essentially for image crystallography on organic/biological matter. Much research was done, especially with the Siemens instrument, also by visiting scientists from many parts of the world. The substances studied included tungsten and molybdenum oxides, including ‘shear structures’, and tungsten bronzes and other ternary tungsten oxides, but also – in collaboration with other research groups – other materials, such as dental plaque and bone, hydrogen storage material and rapidly quenched metals. Computer-based image simulation was also introduced, partly in cooperation with foreign scientists, as an aid for interpretation of the images.
The lack of a SEM was felt increasingly troublesome but the situation could be temporarily unravelled by a donation of a 12 years old JEM-U3 by a nearby company in 1980. It was equipped with a Link-860 EDS system, and was very much used by many research groups.
The resolution power of electron microscopes developed rapidly on a commercial basis during the 70-ties as research had demonstrated that imaging could go below unit cell level. The need for better resolution than that offered by the Siemens instrument was crucial to further progress and a JEM-200CX with top-entry stage and 2.4 Å resolution could be bought in 1982. This 200 kV microscope with LaB6 cathode was much in use for almost 20 years, when it had to leave the scene, replaced by a JEM-3010 from Japan.
To facilitate image interpretation a Kontron IBAS/IPS image processing system was acquired in 1984, which could be used on-line with the 200CX and, later, with the JSM-880 SEM instrument. Two SEM instrument could namely be bought in 1987, to replace the almost 20-years old scanning electron microscope we had. A JSM-820 standard SEM and a JSM-880 ‘high-resolution’ instrument (15 Å resolution) were acquired, both provided with Link EDS detectors (the latter with a thin-window spectrometer) connected to an X-ray microanalysis system. Both instruments, but particularly the JSM-820, have been used very much by practically all research groups at the Department for over 19 years!
To make possible the simultaneous identification of a crystallite by electron diffraction and determination of its composition by EDX a JEM-2000 FX (200 kV) could be bought in 1988. It has a side-entry double-tilt goniometer and a Link QX200 X-ray microanalysis system attached. CBED is also possible on this microscope. The need for this instrument is demonstrated by its booking list, which has been nearly full in daytime for all 19 years it has been in use.
In the 90-ties the 200CX was felt increasingly old-fashioned and the need for a more modern high-resolution instrument became urgent. A 300 kV JEM-3010 with high-resolution pole-piece (resolution 1.7 Å) and motor-driven double-tilt side-entry goniometer could be acquired in 1994. It has a LaB6 cathode and an image pick-up system so that images can be directly transferred to a computer for processing. Intentionally, it was not equipped with an EDX system to avoid compromises on the resolution. It has been used over the years by many different research groups.
All TEM microscopes, except the first two, were acquired thanks to generous donations by the Knut and Alice Wallenberg Foundation.
In August 1979 we arranged a Nobel symposium at Lidingö on "Direct Imaging of Atoms in Crystal and Molecules", with 33 invited experts from all over the world and 12 observers, who also took part in the discussions. A EUCHEM conference on “High Resolution Electron Microscopy in Solid State Chemistry” was arranged at Skepparholmen (Stockholm) in June 1983 and another EUCHEM conference on “Electron Crystallography” at Skytteholm (Stockholm), by the electron crystallography group, in June 1996.