The BICEP2 CMB polarization experiment
The Bicep2 telescope is designed to measure the polarization of the cosmic microwave background on angular scales near 2-4 degrees, near the expected peak of the B-mode polarization signal induced by primordial gravitational waves from inflation. Bicep2 follows the success of Bicep, which has set the most sensitive current limits on B-modes on 2-4 degree scales. The experiment adopts a new detector design in which beam-defining slot antennas are coupled to TES detectors photolithographically patterned in the same silicon wafer, with multiplexing SQUID readout. Bicep2 takes advantage of this design's higher focal-plane packing density, ease of fabrication, and multiplexing readout to field more detectors than Bicep1, improving mapping speed by nearly a factor of 10. Bicep2 was deployed to the South Pole in November 2009 with 500 polarization-sensitive detectors at 150 GHz, and is funded for two seasons of observation. The first months' data demonstrate the performance of the Caltech/JPL antenna-coupled TES arrays, and two years of observation with Bicep2 will achieve unprecedented sensitivity to B-modes on degree angular scales.
Additional Information© 2010 SPIE. The International Society for Optical Engineering. This paper is dedicated to the memory of Andrew Lange, who died under tragic circumstances in January 2010. Andrew made invaluable contributions to the field of experimental cosmology. He played a central role in the conception of the BICEP2 and Keck experiments. His scientific aptitude, leadership, and unique abilities to recognize and develop young scientists are sorely missed by his friends and colleagues. Bicep2 has been made possible by support from the National Science Foundation, Grant No. ANT-0742818. Detector development has been made possible by the generous support of the Gordon and Betty Moore Foundation. RWO gratefully acknowledges support from the Kavli Institute for Particle Astrophysics and Cosmology. We are grateful to have Steffen Richter as our 2010 South Pole winter-over. The Bicep2 team would also like to thank the South Pole Station staff for logistical support. We thank our Bicep, Keck Array, and Spider colleagues for useful discussions and shared expertise. Finally we wish to thank Barbara Wertz and Kathy Deniston for their tireless logistical and administrative support.
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