Advanced modelling and combined data analysis of Planck focal plane instruments

The main topic of my PhD work is the software modelling of the ESA Planck Low Frequency Instrument (LFI) radiometers. The software model, implemented in QUCS, relies on measured frequency response of the LFI radiometers components and on an analytical waveguide simulator in order to simulate the LFI bandpasses channel by channel. Modelled bandpasses showed good consistency with the measured performance and suffered less systematic effects, they are therefore the best estimate available for the radiometers frequency response. Thanks to the collaboration with Jean-Michel Lamarre, HFI Instrument Scientist, the bolometric instrument on-board Planck, the focus of my activity was broadened and included the study of cross-correlation between HFI and LFI data, on two main aspects: The computation of the thermal transfer functions of the stage at 4K during tests and from simulations. The 4K stage is a key element in the HFI cryogenic chain and it is used as a stable reference load by LFI. The design of quick look analysis sessions exploiting both instruments scientific and housekeeping data in order to identify systematic effects. Sessions relies on the data visualization software KST and consist of a set of already implemented and tested basic sessions, allowing for example to produce spectra and cross-correlations, and a set of advanced sessions, dedicated on the study of a specific aspect, for example the correlation between LFI 70 GHz and HFI 100 GHz channels.