R\&D Studies of a Lead-Scintillating Fiber Calorimeter as a STAR Forward Detector

A forward upgrade of the STAR detector will achieve several physics goals. Examples are studying the internal structure of nucleons and nuclei through measurement of di-jets and Drell-Yan and improvements in the resolution of energy weighted event plane determination for study of more central and more peripheral events in heavy-ion collisions. The AGS E864 lead-scintillating fiber calorimeter cells ($(10\,cm)^2 \times 117\,cm$) were repurposed by pixelizing their readout into a three by three array of $(3.3\,cm)^2$ pixels. A prototype six by six array of these cells (324 pixels) was mounted on the west side of the STAR detector during Run14 and events from $^{3}$He+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV were recorded. The detector response was simulated by a GEANT model using HIJING particle production. Further tests of the pixelized cells were conducted at the Fermilab Test Beam Facility. In this talk, we will present the calorimeter response in $^3$He+Au collisions using reconstructed $\pi^0$ from clusters formed from energy deposition by $\pi^0$ decay gammas. Energy resolution and shower shapes from pixelization are also discussed using test beam data and simulations.