  We present the status of on-going detector development efforts for our joint
NASA/CNES balloon-borne UV multi-object spectrograph, the Faint Intergalactic
Redshifted Emission Balloon (FIREBall-2; FB-2). FB-2 demonstrates a new UV
detector technology, the delta-doped Electron Multiplying CCD (EMCCD), in a low
risk suborbital environment, to prove the performance of EMCCDs for future
space missions and Technology Readiness Level (TRL) advancement. EMCCDs can be
used in photon counting (PC) mode to achieve extremely low readout noise ($<$1
electron). Our testing has focused on reducing clock-induced-charge (CIC)
through wave shaping and well depth optimization with a \nuvu V2 CCCP
Controller, measuring CIC at 0.001 e$^{-}$/pixel/frame. This optimization also
includes methods for reducing dark current, via cooling, and substrate voltage
levels. We discuss the challenges of removing cosmic rays, which are also
amplified by these detectors, as well as a data reduction pipeline designed for
our noise measurement objectives. FB-2 flew in 2018, providing the first time
an EMCCD was used for UV observations in the stratosphere. FB-2 is currently
being built up to fly again in 2020, and improvements are being made to the
EMCCD to continue optimizing its performance for better noise control.
