# An automated system to measure the quantum efficiency of CCDs for astronomy

## TL;DR

This paper presents an automated system designed to accurately measure the quantum efficiency of large CCD sensors across a broad wavelength range, supporting the construction of the LSST camera.

## Contribution

It introduces a novel automated measurement system capable of precise quantum efficiency assessment for large CCD sensors in astronomy.

## Key findings

- Achieved 7% accuracy in quantum efficiency measurements.
- Developed a uniform photon flux system for large sensors.
- Enabled scalable testing for LSST camera components.

## Abstract

We describe a system to measure the Quantum Efficiency in the wavelength range of 300 nm to 1100 nm of 40x40 mm n-channel CCD sensors for the construction of the 3.2 gigapixel LSST focal plane. The technique uses a series of instrument to create a very uniform flux of photons of controllable intensity in the wavelength range of interest across the face the sensor. This allows the absolute Quantum Efficiency to be measured with an accuracy in the 7% range. This system will be part of a production facility at Brookhaven National Lab for the basic component of the LSST camera.