Black and white photographic print showing the passage of a positron through a 0.35 cm. lead plate
Black and white photographic print showing the passage of a positron through a 0.35 cm. lead plate, with the production of two further tracks below the plate, taken on Pike's Peak, by Carl David Anderson and Seth H. Neddermeyer, at the California Institute of Technology, Pasadena, California, United States, 1935-1937