JEM Gamma Radiation Exposure Calculator for Industrial Radiography (ca. 1960s) |
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| There is not much to say about this slide rule that can't be learned from reading the text in the photos. It's purpose was simple: to calculate the appropriate exposure times in gamma radiography for Co-60 and Ir-192 sources. |
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The small unreadable print on the front of the slide rule states "Slide-Chart Corp. 1962, PERRYGRAF Corp., Maywood, Ill." Based on that, I am assuming that it was produced sometime during the 1960s. Nevertheless, it certainly could have been later. |
