Historical Context:
The Stereoscan S4-10 represents the fourth iteration of the Scanning Electron Microscope (SEM) model developed and manufactured by Cambridge Ltd. in the United Kingdom (UK). It stands as an improved version of the original commercial Scanning Electron Microscope, the Stereoscan MK1. Introduced in 1972, it combined Vacuum Tube (Valve) and Semiconductor Circuits, positioning it as one of the most advanced microscopes at the time.
The lineage of Stereoscan Scanning Electron Microscopes can be traced back to the pioneering work of Prof. Oatly at the University of Cambridge in the UK. It builds upon the foundational contributions of scientists such as Manfred von Ardenne, Max Knoll, Vladimir Zworkin, and James Hillier, among others. Notably, the Stereoscan MK1 democratized access to scanning electron microscopy for average researchers, as prior to its introduction, SEMs were predominantly utilized by physicists who constructed their own machines.
About:
The Stereoscan S4-10, currently showcased at our DemoSpace, was originally acquired by the Geology Department of the University of Heidelberg, where it served for many years. During its use, it featured an early type of LaB6 (Lanthanum Hexaboride) cathode, utilizing a unique Electron Beam furnace/evaporator source arrangement to heat the LaB6 cathode via electron bombardment. Unlike modern LaB6 cathodes, which use resistive heating, this arrangement is notable for its type and shape of LaB6 employed. A further difference between contemporary LaB6 cathodes, which are single crystals of small size, this historical LaB6 cathode consists of a LaB6 ceramic rod, pressed and sintered into the shape of a square rod tipped with a pyramid emitting electrons.
Presently, this LaB6 cathode is not installed in the machine due to time constraints and significant usage challenges. Therefore, in the interest of presenting a functional machine requiring minimal maintenance to the public, the more common Tungsten Hairpin cathode is currently utilized. However, the LaB6 cathode may be reinstated into the machine at a future, yet undetermined time. This exceptional cathode is displayed in display in a show case, alongside other cathode types utilized in electron microscopy, allowing visitors to discern the vast differences between this polycrystalline LaB6 cathode and the single crystal cathodes used in contemporary Electron Microscopes.
After its service at the University of Heidelberg, the S4-10 came into the possession of Stefan Diller, a founding member of the Museum, who utilized it for Scientific Photography. Diller upgraded this machine to include three Secondary Electron Detectors, as visible in its current display. These detectors, used with a Point Electronics DOSDISS digital interface, facilitated the creation of stunning scientific artworks. By assigning each detector to a color channel – Red, Green, and Blue – grayscale images typical of Electron Microscope imagery are transformed into vibrant, colored art. Conceptually, the detector’s position can be compared to the placement of a light source in conventional photography, enabling the illumination of a sample by three different colored lights from three directions, each 90° apart.
The microscope was upgraded to the advanced Phillips 515 model before being relocated to the Netherlands, where it operated for several years before being stored about a decade ago. In September 2023, Mr. Diller, the previous owner, brought the device to the Electron Microscopy Museum Nuremberg. As the chairman of the association, Mr. Diller is keen on ensuring the inclusion of this remarkable device in the collection.
