Tracking radiation damage of Euclid VIS detectors after 1 year in space

TL;DR

This paper reports on the first year of radiation damage monitoring in Euclid's VIS detectors in space, using trap pumping to detect defects and assess their impact on image quality for galaxy shape measurements.

Contribution

It introduces the first in-space application of trap pumping for CCD defect detection, providing new insights into radiation damage evolution in space-based detectors.

Findings

Radiation-induced defects increased over the first year in space.

Trap pumping effectively detects and characterizes CCD defects.

Data informs radiation damage correction methods for Euclid.

Abstract

Due to the space radiation environment at L2, ESA's Euclid mission will be subject to a large amount of highly energetic particles over its lifetime. These particles can cause damage to the detectors by creating defects in the silicon lattice. These defects degrade the returned image in several ways, one example being a degradation of the Charge Transfer Efficiency, which appears as readout trails in the image data. This can be problematic for the Euclid VIS instrument, which aims to measure the shapes of galaxies to a very high degree of accuracy. Using a special clocking technique called trap pumping, the single defects in the CCDs can be detected and characterised. Being the first instrument in space with this capability, it will provide novel insights into the creation and evolution of radiation-induced defects and give input to the radiation damage correction of the scientific data. We present the status of the radiation damage of the Euclid VIS CCDs and how it has evolved over the first year in space.