Angular Correlation of Scattered Annihilation Radiation.

According to pair theory, the polarization planes of the two quanta emitted in the annihilation of a positron-electron pair with zero relative angular moment,urn should be perpendicular to each other. The experiment verifying the prediction of the theory w~s first proposed by W ~ L ~ R 0); let two annihilation quanta strike two scatterers and let the resulting Compton scattered quanta be recorded in coincidence. Since Compton scattering is more probable in directions perpendicular to the electric veel or of a gamm~ r~y than parallel to it, the rate of coincidences will depend on the relative azimuthal angle qb = (~)1 (~2 Of lhe two detectors, if there is a correlation between the polarization planes of the two quanta. The ratio o between the coincidence counts when the two detectors are at right: angles to each other and the coincidence counts when the detectors ~re coplanar has been calculated by S~YD~¢, ])ASTERNACK and HORNBOSTEL (2) for differenl scattering angles 0. Moreover they calculated the o ratio for a finite