Radiography of Platinum by Means of Channeled Alpha Particles

Alpha particles emitted from a radioactive source and traversing a metallic foil of adequate thickness emerge only if they are channeled in the metal. They produce an image on a collector. It is shown that this image is strongly affected by lattice defects existing in the foil. Recrystallization of platinum is observed. The activation energy is measured: E=(2.85±0.15) eV. Zones of enhanced channeling exist in the metal along {111} and {100} planes, producing geometrical patterns on the image.