Analysis of calibration data from the detectors on the Gaia focal plane has shown that the amount of radiation damage is much lower than predicted based on the pre-launch testing. The contributing factors to this lower level of damage are unconfirmed, although there are several candidates for this variation. One is the increased optical background from light scattering from fibres and ice on the end of the baffle. Another is the impact of the devices being irradiated in-orbit more than 100 K lower in temperature than in the pre-launch test campaigns. Current research at the Open University (OU) suggests that both factors have a major impact on the level of damage received. Simulations developed for the ESA Euclid mission using similar detectors, albeit of a different design, are showing great promise in aiding an understanding of the physics behind the processes of radiation damage in these detectors. A Gaia NPI will allow access to pre-launch test data, post-launch calibration data and also the ability to obtain new test data from the Gaia test bench situated at ESTEC. Using this data, alongside developing the OU simulations to the Gaia detectors, the student will be able to get real information on traps developing in the detectors in-orbit, feeding this information back into other mission research (e.g. Euclid, SMILE, WFIRST etc). The student will then go on to look at how the radiation damage will affect the Gaia output from an astronomy perspective during the mission. Smearing caused by radiation damage can lead to an increased blending of the object of interest with fainter background objects and this could therefore lead to an increased uncertainty in the radial velocity measurements. As the radiation damage builds over time, the uncertainties will also increase and an analysis of this effect and a possible way to correct for it would therefore be of major interest and will have benefits to other space astronomy missions such as ESAs Euclid and PLATO missions.
