Neutron Photoproduction Cross Sections of Lanthanum and Praseodymium

The ($\gamma , n$) cross sections for La and Pr have been determined from threshold to 30 MeV. The two cross sections are similar, and both deviate from a Lorentz line shape. The parameters for the two cross sections are La, ${\sigma }_m=304\mathrm{}$ mb $E_m=14.5\mathrm{}$ MeV, ${\sigma }_{\mathrm{int}}=1.36\mathrm{}$ MeVb, ${\Gamma }_{\mathrm{Lor}}=3.3\mathrm{}$ MeV; Pr ${\sigma }_m=305\mathrm{}$ mb, $E_m=14.8\mathrm{}$ MeV, ${\sigma }_{\mathrm{int}}=1.47\mathrm{}$ MeVb, ${\Gamma }_{\mathrm{Lor}}=3.3\mathrm{}$ MeV.