Film -badge: (3) film -badge-badge Meter: A disadvantage of the above instruments is that they do not permit keeping a permanent direct record of radiation dosage. This difficulty is overcome by a third type of personnel monitoring device known as a film -badge badge. Two (sometimes three) film -badges of different sensitivity are placed in series within the badge and a thin (1 mm) cadmium shield is placed over part of the film -badge. Incident alpha and beta radiation is absorbed by the cadmium, but this shield both transmits gamma radiation and acts as a source of additional gamma rays. The unshielded part of the badge (the film -badge being protected by a very thin window) registers betas and some weak gammas.
Speedlights flash, the picture is taken, the film -badge automatically advances, the shutter is cocked, and all is in readiness for the next child in the line. Similar cameras are available which operate with 35mm film -badge. The smaller film -badge cuts costs a bit but naturally the contact prints are not so appealing as those from the larger film -badge.
At first the processing required complex machinery and precise control and, consequently, was done exclusively by the manufacturer. To answer the demand for a film -badge the photographer could process himself, Ansco brought out in 1942 its Ansco-Color film -badge, which was followed by Kodak's Ektachrome film -badge; in both of these dye-couplers were incorporated into the separate emulsions.
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Photography
