Calculs de la correction couIombienne dans Ie phénomène de production de paire par des rayons γ d’énergie comprise entre 2 et 20 MeV

Summary  We present an extension of the Bethe and Maximon calculation for pair production by photons of intermediate energies (2 to 20 MeV). We include in the matrix element the main terms omitted by those authors. We show that the correction term that we introduce can be of the same order of magnitude than the leading one, especially for pair production by low-energy photons (∼ 2 MeV) in the field of heavy elements. Our results are valid for all values of the pair opening angle, but the screening is assumed to be negligible.