16 mm Camera for Recording Movement of Electroscope Fibers ( 1930s)
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.
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
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
The figure to the right shows two sections of 16 mm film indicating the normal fluctuations of cosmic rays and two ionization bursts.
Last updated: 07/25/07
Copyright 1999, Oak Ridge Associated Universities