Assessment of proton radiation-induced charge transfer inefficiency in the CCD273 detector for the Euclid Dark Energy Mission

摘要

Euclid is a medium class mission selected for launch in 2019, with a primary goal to study the dark universe using the weak lensing and baryonic acoustic oscillations techniques. Weak lensing depends on accurate shape measurements, therefore it is beneficial that the effects of radiation-induced charge transfer inefficiency (CTI) in the Euclid CCD over the six year mission are understood and minimised. This paper describes the initial evaluation of the tolerance to radiation induced charge transfer inefficiency (CTI) of the CCD273 produced by e2v technologies plc, making comparisons with the previous CCD selected for Euclid the CCD203. The CCD273 benefits from the inclusion of a charge injection structure for trap suppression and a reduction in the register channel width. The improvement in tolerance to radiation induced serial CTI achieved by reducing the channel width from 50 um to 20 um was measured experimentally to be a factor of 1.7, which compares well to a factor of 1.9 found using a charge volume model.