This museum item is an Equi-Inclinational Diffractometer, designed by Martin Julian Buerger (MIT), built by Charles Supper Inc. It was made in Boston USA around 1970. Martin Buerger was an American crystallographer born in 1903. He invented the X-ray Precession camera for studying crystals. The MJ Buerger Award was established in his honor.
This kind of instrument is designed to analyze the structure of a material by measuring the scattering pattern that is produced when a beam of radiation or particles, for example X rays or neutrons is shone on it. Different beams have different advantages. Electrons cannot penetrate very far into a sample and so are normally used to explore the surface of the sample. Neutrons and X-rays can penetrate into objects and so are used to explore the interior structure. Neutrons have the added advantage of possessing an intrinsic magnetic moment. This causes them to interact differently with atoms with different magnetic moment alignments.
This particular diffractometer uses an X-ray beam. With a previously aligned crystal, it collects in two dimensions the intensities of hkl reflections by making a 1D scan through the peak. For further upper level reflections the device has to be manually changed. The detector is a Philips scintillation counter.
It was the first computer controlled diffractometer in Australia and was run in the laboratory of Professor Hans Freeman of Sydney University, who kindly donated it to Dr Colin Kennard at UQ. Freeman had done his PhD with Linus Pauling. It came with a PDP-8, a small computer which frequently gave the users trouble. By 1989 Kennard had better equipment and did not use the diffractometer anymore, so it did not produce many publishable results at UQ. It was successfully used in a project with Mervin Hegarty of CSIRO concerning a compound in an imported grass that caused miscarriges in sheep.
This item is part of the UQ Physics Museum Crystallography Tour
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