This museum piece is an X-ray Spectrometer. It was designed by Dr Muller and made by an English firm Adam Hilger. The spectrometer was designed to be extremely compact while still being sufficiently accurate for use in classrooms. It would have been used by advanced students to study the diffraction pattern that resulted when an X-ray beam was shone through a sample. From this information the students would have been able to determine the space lattice structure of the sample and hence analyse its properties. This particular spectrometer was used in the teaching laboratories of UQ for various experiments involving the observation and measurement of X-ray behaviour, diffraction patterns and crystal structure.
The spectrometer has a rectangular iron base which encloses a spring drive. Above the base is a hollow iron box and a thin slit; followed by a rotating crystal mount and a sheet of photographic film that is mounted in a brass arc. The sides of the device are enclosed by lead shielding, leaving the top and bottom open. This shielding is to protect the user against the X-ray radiation. The sample to be studied, normally a piece of crystal, would be mounted in the center of the device. The spring drive powers a toothed wheel which can be used to rotate the crystal. The mount can also be tilted. An X-ray beam would then be shone through the crystal and the resulting diffraction pattern would be recorded on the strip of photographic film in the curved holder, which could then be removed and studied.
Crystals are made up of a geometrically regular lattice of atoms. When X-rays fall incident on the crystal lattice they have the potential to be reflected by the planes formed by the electron clouds of the atoms. Some rays will be reflected by the first plane while the rest pass through to the second. The process repeats itself at each layer, forming a diffraction pattern. By examining the light that passes through the crystal, a user can determine the density and placement of the atoms and electrons in the crystal.
Adam Hilger Ltd was a maker of optical instruments and was founded in 1904 in London. In 1937 it was incorporated into Cambridge Instrument Co. Ltd but continued to trade under its original name until it closed in 1948. After 1948 the company became part of Hilger and Watts.
This item is part of the UQ Physics Museum Crystallography Tour
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