Photon counting with intensified charge coupled device (ICCD) – I. In-depth detector characterization

This study presents an in-depth characterization of an intensified charge-coupled device (ICCD) for low-light measurement, with a focus on identifying single-photon events in spectroscopic applications. The objective is to establish a foundation for using ICCDs in photon counting (PC), which offers advantages over conventional analog detector readout, as demonstrated in Part II of this study with laser-induced breakdown spectroscopy. Emphasis is placed on optimization of ICCD operating parameters for effective differentiation between signal spikes and detector noise. Detector dark noise, threshold setting for single-photon detection, and ICCD operating parameters such as intensifier gain, analog-to-digital conversion rate, and pre-amplifier setting, are characterized and discussed. The intensifier gain is identified as the most critical parameter, significantly affecting signal spike size and ion feedback phenomena. A systematic approach is proposed for selecting optimized operating parameters between minimizing false positives and maximizing counting efficiency.