Delta-doped Electron Multiplying CCDs for FIREBall-2.

Abstract. We present the status of on-going detector development efforts for our joint NASA/CNES balloon14borne UV multi-object spectrograph, the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2; FB-2). FB-215 demonstrates a new UV detector technology, the delta-doped Electron Multiplying CCD (EMCCD), in a low risk16 suborbital environment, to prove the performance of EMCCDs for future space missions and Technology Readiness17 Level (TRL) advancement. EMCCDs can be used in photon counting (PC) mode to achieve extremely low readout18 noise (<1 electron). Our testing has focused on reducing clock-induced-charge (CIC) through wave shaping and well19 depth optimization with a Nu¨vu¨ V2 CCCP Controller, measuring CIC at 0.001 e􀀀/pixel/frame. This optimization also20 includes methods for reducing dark current, via cooling, and substrate voltage levels. We discuss the challenges of21 removing cosmic rays, which are also amplified by these detectors, as well as a data reduction pipeline designed for our22 noise measurement objectives. FB-2 flew in 2018, providing the first time an EMCCD was used for UV observations23 in the stratosphere. FB-2 is currently being built up to fly again in 2020, and improvements are being made to the24 EMCCD to continue optimizing its performance for better noise control.