Insert in Hall D at JLab*

The Jefferson Lab Eta Factory (JEF) experiment will test QCD at the confinement scale and search for new physics beyond the Standard Model in the eta and eta' meson decays. This experiment will utilize the GlueX apparatus and an upgraded Forward Calorimeter (FCAL-II) with a high resolution and high granularity PbWO₄ crystal calorimeter in the central region to suppress the backgrounds due to overlap showers in the calorimeter for the eta and eta' rare decay channels. This PbWO₄ Calorimeter will consist of 1596 crystal modules. The design of FCAL-II and the current status of development will be discussed.