Photograph showing the tracks of recoil atoms
Photograph showing the tracks of recoil atoms from the natural disintegration of actinon and actinium A (from Iréne Joliot-Curie and Frédéric Joliot)
Photograph showing the tracks of recoil atoms from the natural disintegration of actinon and actinium A (from Iréne Joliot-Curie and Frédéric Joliot)