| Abstract: | The gamma rays emitted from three photon annihilation of positrons and electrons were selected with a triple coincidence method and the linear polarization of one of the three photons was investigated by using Compton scattering. Under two geometric conditions of three photons annihilation (α1=α2=α3=120° and α1=90°, α2=α3=135°), the ratio of the scattered photons which were parallel with the annihilation plane to those perpendicular with the annihilation plane were 1.82±0.06 and 1.53±0.08, thus the linear polarization of the photons to the annihilation plane were 0.56±0.04 and 0.40±0.09. |
