A far infrared polarimeter

Abstract We describe an experiment to measure calibration sources, the polarization of Cosmic Microwave Background Radiation (CMBR) and the polarization induced on the CMBR from S–Z effects, using a polarimeter, MITOPol, that will be employed at the MITO telescope. Two modulation methods are presented and compared: an amplitude modulation with a Fresnel double rhomb and a phase modulation with a modified Martin–Puplett interferometer. A first light is presented from the campaign (summer 2003) that has permitted to estimate the instrument spurious polarization using the second modulation method.