Measurements of electron-pair-production cross sections

A number of cross sections associated with electron pair production have been measured in the photon energy range 10-300 MeV in Ilford G-5 emulsion ($Z_{eff}\simeq 21$). Measurements include the distribution of the recoil momentum and scattering angle of the target nucleus, the divergence angle between the pair members, the energy partition, the effect of photon polarization, and the absolute pair production cross section. Agreements and disagreements with the theory and previous measurements are discussed.