Challenges in CMB polarimetry for SPIDER and future experiments
In this talk I will introduce SPIDER: a balloon-borne CMB polarimeter, and present preliminary results from its 2015 Antarctic flight. The main focus of SPIDER is detecting or constraining a so-called B-mode component in the CMB polarisation field that matches the signal from a stochastic background of gravitational waves predicted by the simplest models of inflation. Disentangling this signal from other B-mode sources caused by weak gravitational lensing, polarized astrophysical sources and instrumental effects poses an enormous challenge for current and upcoming experiments. I will give an overview of these B-mode contaminants and conclude with a more detailed look at spurious B-modes caused by incomplete modelling of the instrument’s optical response and possible ways to avoid them or correct for them.