The White Mountain Polarimeter Telescope and an Upper Limit on CMB Polarization

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 Department of Physics, University of California, Santa Barbara, CA 93106 University of California, White Mountain Research Station, Bishop, CA 93514 University of California, Santa Barbara Center for High Altitude Astrophysics at White Mountain, University of California, Santa Barbara, CA 93106 Now at Raytheon Vision Systems, Goleta, CA 93117 Instituto Nacional de Pesquisas Espaciais, Divisao de Astrofisica, Caixa Postal 515, Sao Jose dos Campos, SP 12210-070, Brazil Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria, 16, 20133 Milano, Italy IFP-CNR, Via Roberto Cozzi, 53, 20125 Milano, Italy Now at Department of Physics, New Mexico Institute of Mining and Technology, Socorro, NM 87801 Now at California Institute of Technology, Pasadena, CA 91125 INAF-IASF Bologna, Via P. Gobetti, 101, 40129 Bologna, Italy Department of Physics, University of Wisconsin, Madison, WI 53706