This X-ray Powder Camera is a device used for recording the diffraction patterns of x-rays caused by powdered samples. It consists of a circular metal base onto which a cylindrical cover can be placed and fastened securely using three levers spaced evenly around its body. The cover is marked with the initials ‘P.L.U.Q.’, indicating it was used in the Physics laboratories at the University of Queensland. The camera also came with a bottle of capillary tubes, marked ‘25 Glaskapillaren’ or ‘25 glass capillaries’. These are known as Lindemann capillaries, and are made of borosilicate glass which has a low absorption of X-rays.
When using the camera, the user would grind the sample of their crystal into powder in an agate mortar, and then load it into one of the glass capillaries. This sample-filled capillary is then loaded into the centre of the camera. To record the image of the x-ray diffraction, the user then inserted a specially-cut strip of 35mm x-ray film. This film was a long strip that wrapped around the inside of the cylindrical cover, forming a complete circular band of film. The film was also specially punctured to allow the x-rays to pass through it as they entered the camera. The x-rays then undergo scattering from the powdered material and form a cone-shaped diffraction pattern. The way the film is arranged means that the strip will show a series of expanding lines that mark the interference lines. A spigot was provided on top of the device to allow the chamber to be evacuated.
This item is part of the UQ Physics Museum Crystallography Tour
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