Ernest Wollan's Film Badge from Manhattan Project (ca.1943)

This is an example of the film badge developed (pun intended) by Ernest Wollan for use at the University of Chicago's Metallurgical Laboratory during World War II. 

Film had been used previously (as early as 1905) to evaluate radiation exposures, but in most cases the techniques were relatively primitive. For example, one method that was used well into the 1930s involved holding the developed film against a newspaper. If the newspaper could be read through the film, the exposure was low enough to be acceptable.

The photo to the right shows the version of Wollan's badge used at Oak Ridge National Laboratory ca. 1950. Note the number: 0000 (pretty cool).

Badges donated by Herb Pomerance and John Wollan

A key feature of the badge was that it employed filtration (1 mm cadmium) to reduce the variations in the film's response (accuracy) to radiation of different energies.

Wollan headed up the radiation protection program at Chicago during the Manhattan project and he was the first person to employ the title "Health Physicist."  For a story regarding Wollan's accomplishments, click here.

The inspiration for the design was a film badge that Carl Braestrup had been deploying in New York City hospitals since the early 1930s. The problem that Braestrup had been faced with was that the device's accuracy depended on the energy of the photons (x-rays or gamma rays) to which it was exposed. In a hospital setting, a wide range of energies could be encountered: x-ray units emitted low energy photons whereas radium sources emitted some very high energy gamma rays. By incorporating metal filters into the badge, the photon energy could be estimated. Once the energy was known, any necessary corrections to the response of the film would be made.

At the start of World War II, Braestrup was contacted by some people at the Metallurgical Laboratory to find out if he had taken out a patent on the dosimeter. If he had done so, he would have become a very rich man, but he hadn't. In any event, the folk in Chicago used Braestrup’s design as the basis for the film badge used in the Manhattan Project (interview of Carl Braestrup in the BRH Vignettes of Early Radiation Workers).

Reference:

Pardue, Goldstein and Wollan,   Photographic Film as a Pocket Dosimeter, Metallurgical Laboratory Report CH-1553, April, 1944.

US Patent 2,483,991 Radiation Exposure Meter, Ernest Wollan, and Louis Pardue.

Personal communication, Herb Pomerance

 

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Last updated: 07/25/07
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