EBEX: The E and B Experiment

The E and B experiment (EBEX) is a balloon-borne telescope designed to measure the polar- ization of the cosmic microwave background radiation as well as that from Galactic dust. The instrument is equipped with a 1.5 meter aperture Gregorian-Dragone telescope, providing an 8' beam at three frequency bands centered on 150, 250 and 410 GHz. Polarimetry is achieved by rotating an achromatic half-wave plate on a superconducting magnetic bearing. In January 2013, EBEX completed 11 days of observations in a ight over Antarctica covering 6000 square degrees of the sky. This marks the rst time that arrays with about 1000 transition-edge sensor bolometers have made science observations on a balloon-borne platform. These proceedings describe the EBEX instrument, the science ight and the status of the data analysis. 1 I