$^{nat}$Dy$(\gamma,n)$ Asymmetry Measurements with Linearly Polarized $\gamma$-rays between 11 and 15 MeV

The $^{nat}$Dy$(\gamma,n)$ reaction was studied at TUNL's High Intensity $\gamma$-ray Source (HI$\gamma$S) using a linearly polarized photon beam at energies 11, 12, 13, 14, and 15 MeV. Measurements were made using liquid scintillator detectors at angles 55$^{\circ}$, 72$^{\circ}$, 90$^{\circ}$, 107$^{\circ}$, 125$^{\circ}$, 142$^{\circ}$. The ratio of neutrons detected parallel to the plane of polarization compared to perpendicular to the plane of polarization was measured as a function of $E_\gamma$, $E_n$, and $\theta$. This ratio may be useful for distinguishing different isotopes from one another, and $^{nat}$Dy is one among many isotopes measured to date. The experimental set-up is discussed, along with the data analysis procedure used to determine the ratio.