16 mm Camera for Recording Movement of Electroscope Fibers ( 1930s) |
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These unusual looking devices are 16 mm movie cameras designed and built by Hugh Carmichael at the Cavendish Laboratory, ca.1934. The box (ca. 9" x 9" x 2.5") is possibly made of birch while the metal components are brass and steel. The
lens of the camera was focused on the fiber of an electroscope connected
to a large ionization chamber. Cosmic ray interactions in the chamber
would cause a sudden deflection of the fiber and this deflection was
recorded on the slowly advancing (0.1 mm/sec) film. The filming not only
facilitated investigation of these relatively infrequent events, it also
permitted a mathematical analysis that would give the size of an off-scale
deflection. |
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The photograph to the left shows a camera that has been opened up so as to permit a view of the film transport mechanism.
Donated by Hugh Carmichael |
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The figure to the right shows two sections of 16 mm film indicating the normal fluctuations of cosmic rays and two ionization bursts. |
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