Threshold Photoneutron Cross Sections For Pb-206, Pb-207, Pb-208, Fe-56, Fe-57, Cr-52, Cr-53, Mg-24, Mg-25, Mg-26, And F-19

The threshold photoneutron cross sections for $^{206,207,208}\mathrm{Pb}$, $^{56,57}\mathrm{Fe}$, $^{52,53}\mathrm{Cr}$, $^{24,25,26}\mathrm{Mg}$, and $^{19}\mathrm{F}$ have been measured to about 1 MeV above the ($\ensuremath{\gamma},n$) threshold. Cross sections are presented and analyzed for the parameters of over 200 resonances. The results bear on several phenomena of interest in nuclear physics; these include $E1$ strength functions, analog states, doorway states, the $M1$ giant resonance, and nonresonant neutron capture.