Unknown Source Capsule
This metal capsule is 1 3/8" long and 3/8" in diameter. While it was not fabricated at Oak Ridge National Laboratory, these types of containers were loaded there, e.g., with 1-10 Ci or so of Ir-192, Sr-90, and Co-60. After loading, the cap would have been welded shut. The cap, as can be seen in the photo below right, is slotted. How it would have been used is uncertain.
Reference
Karl Haff, personal communication. At different times, Haff headed up ORNL's Source Safety Testing Program and their Radiochemical Processing Program.