Optimization of the half wave plate configuration for the LSPE-SWIPE
  experiment
  The search for the B-mode polarization of Cosmic Microwave Background (CMB)
is the new frontier of observational Cosmology. A B-mode detection would give
an ultimate confirmation to the existence of a primordial Gravitational Wave
(GW) background as predicted in the inflationary scenario. Several experiments
have been designed or planned to observe B-modes. In this work we focus on the
forthcoming Large Scale Polarization Explorer (LSPE) experiment, that will be
devoted to the accurate measurement of CMB polarization at large angular
scales. LSPE consists of a balloon-borne bolometric instrument, the Short
Wavelength Instrument for the Polarization Explorer (SWIPE), and a ground-based
coherent polarimeter array, the STRatospheric Italian Polarimeter (STRIP).
SWIPE will employ a rotating Half Wave Plate (HWP) polarization modulator to
mitigate the systematic effects due to instrumental non-idealities. We present
here preliminary forecasts aimed at optimizing the HWP configuration.
