Beyond CCDs: Characterization of sCMOS detectors for optical astronomy

Modern scientific complementary metal-oxide semiconductor (sCMOS) detectors provide a competitive alternative to charge-coupled devices (CCDs). They boast comparable performances with faster frame rates, lower read noise, higher dynamic range and have lower production costs such that industry favours sCMOS production. We characterized several commercially available sCMOS detectors to gauge the state of this technology for use in optical astronomy. This included large-pixel detectors (e.g. Teledyne Prime 95B, Andor Sona-11) comparable to traditional CCDs, along with one quantitative sCMOS detector, the Hamamatsu Orca-Quest C15550-20UP, which has photon-resolving capability. We found low levels of dark current, read noise, faulty pixels, and fixed pattern noise, as well as >98% linearity across all detectors. The Quest, in particular, had a dark current of 0.008 +/- 0.034 e-/s/px (-20C) and a read noise of 0.37 +/- 0.10 e- (in standard scan). We also tested this detector on-sky to evaluate its photometric accuracy. Our tests demonstrated that sCMOS detectors perform superior to CCDs in optical imaging and provide more readily available alternatives for upcoming optical instruments.