The S-Process Branching-Point at $^{\mathrm{205}}$PB

Accurate neutron-capture cross sections for radioactive nuclei near the line of beta stability are crucial for understanding $s$-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. We consider photon scattering using monoenergetic and 100{\%} linearly polarized photon beams to obtain the photoabsorption cross section on $^{\mathrm{206}}$Pb below the neutron separation energy. This observable becomes an essential ingredient in the Hauser-Feshbach statistical model for calculations of capture cross sections on 205Pb. The newly obtained photoabsorption information is also used to estimate the Maxwellian-averaged radiative cross section of $^{\mathrm{205}}$Pb(n,g)$^{\mathrm{206}}$Pb at 30 keV. The astrophysical impact of this measurement on s-process nucleosynthesis will be discussed.