Developing the active trap model for CCD charge transfer optimisation in large-scale space missions

Abstract

Charge coupled devices (CCDs) have been the detector of choice for large-scale space mission for many years. Although dominant in this field, the charge transfer performance of the technology degrades over time due to the harsh space- radiation environment. Charge transfer performance can be optimized however, but it is often time consuming and expensive due to the many operating modes of the CCDs. A new technique is presented and developed here, which uses new measurements of the trap landscape present in a CCD, to predict changes in charge transfer inefficiency as a function of different variables. By using this technique, it is possible to focus experimental lab testing on key device parameters, potentially saving many months of laboratory effort. Due to the generality of the method, it can be used to optimize the charge transfer performance of any CCD, and as such has many uses across a wide range of fields. Future CCDs variants that will be used in potential space missions (EMCCD and p-channel CCDs) can use this technique to feedback key device performance to the wider mission consortium before devices are available for experimental testing.