Abstract
Energies of positron annihilation radiation from various materials were measured with Ge detectors. Energies of annihilation radiation are clearly smaller than the electron rest mass. The Compton wavelength and the rest mass of electrons were determined to be 2.426310(15) pm and 511003.1±3.2 eV, respectively, with correction of the positronium binding energy by using annihilation radiation from ice. For other cases the differences are attributed to the minimum potentials of positrons in material as well as the binding energies of electrons. However, the differences are deviated from the expected values.
