ORNL Annular Source (late 1950s, early 1960s)
This stainless steel dummy source, manufactured at Oak Ridge National Laboratory (ORNL) in the late 1950s or early 1960s, is 4 3/4" tall. The outer diameter is 1 1/2" and the central channel, which runs all the way through the source, is 1" in diameter. The ORNL source catalog indicates that these annular sources were fabricated in lengths from 4 3/4 to 10 inches long, and diameters from 1.5 to 4 1/2 inches. Not many were produced.
The source material, Cs-137, was in the form of cesium chloride powder. It was sealed inside a container that was sealed inside the outer container seen in the photos. In other words, the radioactive material was doubly encapsulated. It seems from the information in the ORNL catalog that between 100 and 1000 curies were used. With a 100 curie source, the exposure rate in the center of the tube was approximately 50,000 R/hr. Its purpose would have been to irradiate fluids (e.g., blood) flowing through, and possible around, the tube.
- Joe Setaro, personal communication.
- Oak Ridge National Laboratory Catalog of Radio and Stable Isotopes. 4th revision, April 1963.