Pinning Down Low-x Physics With the MPC-EX at RHIC-PHENIX

The evolution of the nuclear parton distribution functions (nPDFs) are an important ingredient to understanding results from heavy ion collisions. A silicon-tungsten preshower detector, the MPC-EX, was added to the front of the existing MPC electromagnetic calorimeter in the PHENIX detector for the 2016 $d$+Au run. Situated at 3<|$\eta$|<4 and full azimuth, the MPC-EX will enhance the capabilities of measuring photons and $\pi^0$s originating from collisions at large $Q^2$ and low-$x$ partons in the gold beam. In this talk I will overview the status of the detector in the 2016 d+Au and discuss the current state of analysis and how it is expected to answer open questions regarding the evolution of nPDFs.