Planck-LFI CPV: Drain currents verification after HYM Tuning

Abstract

As for the same test performed before the Hyper matrix tuning (REF XXX) , this test was devoted to characterise the i-V response of LNAs when Vg1 and Vg2 are independently changed over a defined set of values. In particular , it is aimed at two main purposes: a) compare the radiometers i-V response with data acquired before Hyper Matrix Tuning: this check allows to sort out any possible problems related with the functionality of the LNAs, after the many bias changes characterizing the HYM Tuning procedure. b) Provide a detailed characterization of the radiometer response, with respect to bias changes, in the final operative conditions, that is when the optimal tuned bias are set. In fact, the accurate knowledge of the i-V curves could be useful in order to check, at any time of the Planck mission, possible changes in the radiometers response due to aging , bias fluctuation or to any other criticality.