The six-meter Atacama Cosmology Telescope (ACT) in Chile was built to measure the cosmic microwave background (CMB) at arcminute angular scales. We are building a new polarization sensitive receiver for ACT (ACTPol). ACTPol will characterize the gravitational lensing of the CMB and aims to constrain the sum of the neutrino masses with ~0.05 eV precision, the running of the spectral index of inflation-induced fluctuations, and the primordial helium abundance to better than 1%. Our observing fields will overlap with the SDSS BOSS survey at optical wavelengths, enabling a variety of cross-correlation science, including studies of the growth of cosmic structure from Sunyaev-Zel'dovich observations of clusters of galaxies as well as independent constraints on the sum of the neutrino masses. We describe the science objectives and the initial receiver design.
@article{arxiv.1006.5049,
title = {ACTPol: A polarization-sensitive receiver for the Atacama Cosmology Telescope},
author = {M. D. Niemack and P. A. R. Ade and J. Aguirre and F. Barrientos and J. A. Beall and J. R. Bond and J. Britton and H. M. Cho and S. Das and M. J. Devlin and S. Dicker and J. Dunkley and R. Dunner and J. W. Fowler and A. Hajian and M. Halpern and M. Hasselfield and G. C. Hilton and M. Hilton and J. Hubmayr and J. P. Hughes and L. Infante and K. D. Irwin and N. Jarosik and J. Klein and A. Kosowsky and T. A. Marriage and J. McMahon and F. Menanteau and K. Moodley and J. P. Nibarger and M. R. Nolta and L. A. Page and B. Partridge and E. D. Reese and J. Sievers and D. N. Spergel and S. T. Staggs and R. Thornton and C. Tucker and E. Wollack and K. W. Yoon},
journal= {arXiv preprint arXiv:1006.5049},
year = {2010}
}