Radioactive integrated circuit (IC) devices with radioactive material embedded in the substrate of the IC itself, and including logic for “fingerprinting” (that is, determining characteristics that identify the source of the radioactive source material). Radioactive IC devices with embedded detector hardware that determine aspects of radioactivity such as total dose and/or ambient radiation. Radioactive IC devices that can determine an elapsed time based on radioactive decay rates. Radioactive smoke detector using man-made, relatively short half-life radioactive source material.