EBEX: a balloon-borne CMB polarization experiment

• Published in: SPIE Proceedings, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
• Main Authors: Reichborn-Kjennerud, Britt, Matsumura, Tomotake
• Other Authors: Holland, Wayne S., Zmuidzinas, Jonas
• Format: Book Part
• Language: unknown
• Published: Society of Photo-Optical Instrumentation Engineers 2010
• Subjects: CMB Polarization; EBEX; Balloon-borne; B-mode; Sumner; Antarc*; Antarctica
• Online Access: https://doi.org/10.1117/12.857138

EBEX is a NASA-funded balloon-borne experiment designed to measure the polarization of the cosmic microwave background (CMB). Observations will be made using 1432 transition edge sensor (TES) bolometric detectors read out with frequency multiplexed SQuIDs. EBEX will observe in three frequency bands centered at 150, 250, and 410 GHz, with 768, 384, and 280 detectors in each band, respectively. This broad frequency coverage is designed to provide valuable information about polarized foreground signals from dust. The polarized sky signals will be modulated with an achromatic half wave plate (AHWP) rotating on a superconducting magnetic bearing (SMB) and analyzed with a fixed wire grid polarizer. EBEX will observe a patch covering ~1% of the sky with 8' resolution, allowing for observation of the angular power spectrum from l = 20 to 1000. This will allow EBEX to search for both the primordial B-mode signal predicted by inflation and the anticipated lensing B-mode signal. Calculations to predict EBEX constraints on r using expected noise levels show that, for a likelihood centered around zero and with negligible foregrounds, 99% of the area falls below r = 0.035. This value increases by a factor of 1.6 after a process of foreground subtraction. This estimate does not include systematic uncertainties. An engineering flight was launched in June, 2009, from Ft. Sumner, NM, and the long duration science flight in Antarctica is planned for 2011. These proceedings describe the EBEX instrument and the North American engineering flight. © 2010 SPIE. EBEX is a NASA supported mission through grant numbers NNX08AG40G and NNX07AP36H. We thank Columbia Scientific Balloon Facility for their enthusiastic support of EBEX. We also acknowledge support from CNRS, Minnesota Super Computing Institute and the Science and Technology Facilities Council. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the office of Science of the U.S. Department of Energy under contract No. ...