SCRATA Exposure Calculator for Gamma Radiography (ca. 1960s) |
|
|
| This slide rule was produced for the Steel Castings & Trade Association (SCRATA) by Blundell Harling Limited of Weymouth England. It's purpose was to calculate the appropriate exposure times in gamma radiography. |
|
|
|
The factors that the slide rule took into account were the source nuclide (cobalt, thulium, cesium or iridium), the source activity, the source to film distance, as well as the thickness and density of the material being "x-rayed." It even calculated the decay of iridium sources! |
