SENSEI: Characterization of Single-Electron Events Using a Skipper-CCD

Authors:
  • LBLiron Barak
    Liron Barak
  • IBItay M. Bloch
    Itay M. Bloch
  • ABAna Botti
    Ana Botti
  • MCMariano Cababie
    Mariano Cababie
  • GCGustavo Cancelo
    Gustavo Cancelo
  • LCLuke Chaplinsky
    Luke Chaplinsky
  • FCFernando Chierchie
    Fernando Chierchie
  • MCMichael Crisler
    Michael Crisler
  • ADAlex Drlica-Wagner
    Alex Drlica-Wagner
  • RERouven Essig
    Rouven Essig
  • JEJuan Estrada
    Juan Estrada
  • EEErez Etzion
    Erez Etzion
Preprint
Publisher website
Google Scholar
Abstract
We use a science-grade Skipper Charge Coupled Device (Skipper-CCD) operating in a low-radiation background environment to develop a semi-empirical model that characterizes the origin of single-electron events in CCDs. We identify, separate, and quantify three independent contributions to the single-electron events, which were previously bundled together and classified as ``dark counts'': dark current, amplifier light, and spurious charge. We measure a dark current, which depends on exposure, of (5.89+-0.77)x10^-4 e-/pix/day, and an unprecedentedly low spurious charge contribution of (1.52+-0.07)x10^-4 e-/pix, which is exposure-independent. In addition, we provide a technique to study events produced by light emitted from the amplifier, which allows the detector's operation to be optimized to minimize this effect to a level below the dark-current contribution. Our accurate characterization of the single-electron events allows one to greatly extend the sensitivity of experiments searching for dark matter or coherent neutrino scattering. Moreover, an accurate understanding of the origin of single-electron events is critical to further progress in ongoing R\&D efforts of Skipper and conventional CCDs.