# Single-electron and single-photon sensitivity with a silicon Skipper CCD

## TL;DR

This paper introduces a silicon Skipper CCD with ultra-low noise readout capable of counting single electrons and photons, enabling highly sensitive detection for physics and astronomy applications.

## Contribution

The development of a stable, large-area CCD with reproducible sub-electron readout noise using a non-destructive floating-gate amplifier system.

## Key findings

- Achieved 0.068 e- rms/pix readout noise over millions of pixels
- Enabled precise counting of electrons from 0 to over 1500 per pixel
- Demonstrated capability to detect single photons in optical and near-infrared

## Abstract

We have developed a non-destructive readout system that uses a floating-gate amplifier on a thick, fully depleted charge coupled device (CCD) to achieve ultra-low readout noise of 0.068 e- rms/pix. This is the first time that discrete sub-electron readout noise has been achieved reproducibly over millions of pixels on a stable, large-area detector. This allows the precise counting of the number of electrons in each pixel, ranging from pixels with 0 electrons to more than 1500 electrons. The resulting CCD detector is thus an ultra-sensitive calorimeter. It is also capable of counting single photons in the optical and near-infrared regime. Implementing this innovative non-destructive readout system has a negligible impact on CCD design and fabrication, and there are nearly immediate scientific applications. As a particle detector, this CCD will have unprecedented sensitivity to low-mass dark matter particles and coherent neutrino-nucleus scattering, while astronomical applications include future direct imaging and spectroscopy of exoplanets.