Calorimeter Construction: Precision Measurements of η and η' Decays Using the Jefferson Lab Eta Factory*

We introduce a new experiment conducted in experimental Hall D at the Thomas Jefferson National Accelerator Facility, dubbed the Jefferson Lab Eta Factory (JEF). This forthcoming project will perform precision measurements of various η and η' decays focusing on rare neutral modes. The JEF experiment requires upgrading the inner part of the forward lead glass calorimeter of the GlueX detector with high-granularity and improved resolution lead tungstate scintillating crystals. The new calorimeter consists of 1,596 modules undergoing fabrication. During the summer of 2023, we worked on fabricating the calorimeter modules and performed quality assurance tests using a light-emitting diode. We will give an overview of the design of the calorimeter modules, the fabrication of the modules, and the testing procedure for functionality and their results.