330-PS-1004 (USN 708062):  Navy’s Two Types of Radiation Detectors.  Lieutenant Rosemary Lalferty is holding one of the two types of radiation “dog tags” developed by the U.S. Navy Research Laboratory under sponsorship of the Bureau of Ships, for the protection of its personnel.  The oblong object on the table is the other type.   Both types of “Dosimeters,” which measure the amount of radiation exposure the wearer has experienced, are simple, rugged and inexpensive.  They keep their sensitivity in storage and under extreme heat.  One type uses salt crystals known as Alkali Halides, which are normally transparent but turn blue when exposed to gamma rays.  A U.S. Navy medic can compare the intensity of the shade of blue of the “dog tag” with a color chart and decide on the spot the degree of seriousness of the individual radiation casualty.  Silver-activated phosphate glass is the sensitive element in the other type.  Gamma Rays convert the glass into phosphor which takes on an orange color under ultraviolet light.  The intensity of the color is the measure of the radiation dose.   A quick measure can be made visually.  Accurate measurement can be made with a simple and compact photoelectric “reader.”  Photograph released January 15, 1950.   (6/30/2015).
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