The JLab Eta Factory (JEF) program aims to use decays of the
$\eta$ meson to
study higher order terms in Chiral Pertubation theory, to determine the
up-down quark mass ratio, and to probe for C-violating/P-conserving processes
and other physics beyond the Standard Model. The program will take place at
Jefferson Lab using the GlueX detector in Hall D. This article focuses on
the rare $\eta\to\pi^0\gamma\gamma$ decay, which requires an upgrade to the
existing forward calorimeter in the GlueX detector.