The White Mountain Polarimeter (WMPol) is a dedicated ground-based microwave telescope and receiver system for observing polarization of the Cosmic Microwave Background. WMPol is located at an altitude of 3880 meters on a plateau in the White Mountains of Eastern California, USA, at the Barcroft Facility of the University of California White Mountain Research Station. Presented here is a description of the instrument and the data collected during April through October 2004. We set an upper limit on E-mode polarization of 14 μK (95% confidence limit) in the multipole range 170<ℓ<240. This result was obtained with 422 hours of observations of a 3 deg2 sky area about the North Celestial Pole, using a 42 GHz polarimeter. This upper limit is consistent with EE polarization predicted from a standard Λ-CDM concordance model.
@article{arxiv.0804.3634,
title = {The White Mountain Polarimeter Telescope and an Upper Limit on CMB Polarization},
author = {Alan R. Levy and Rodrigo Leonardi and Markus Ansmann and Marco Bersanelli and Jeffery Childers and Terrence D. Cole and Ocleto D'Arcangelo and G. Vietor Davis and Philip M. Lubin and Joshua Marvil and Peter R. Meinhold and Gerald Miller and Hugh O`Neill and Fabrizio Stavola and Nathan C. Stebor and Peter T. Timbie and Maarten van der Heide and Fabrizio Villa and Thyrso Villela and Brian D. Williams and Carlos A. Wuensche},
journal= {arXiv preprint arXiv:0804.3634},
year = {2009}
}