GroundBIRD: Observing Cosmic Microwave Polarization at Large Angular Scale with Kinetic Inductance Detectors and High-Speed Rotating Telescope
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Cosmic microwave background (CMB) is an important source of information about the origin of our universe. In particular, odd-parity large angular scale patterns in the CMB polarization, the primordial B-modes, are strong evidence for an inflationary universe, related to the accelerating expansion of the metric. We are developing a unique telescope, GroundBIRD, to take CMB polarization measurements. The telescope combines novel techniques: high-speed rotation scanning, cold optics, and microwave kinetic inductance detectors (MKIDs). We evaluated the response of MKIDs on the rotation stage. Method of shielding from the geo-magnetic field is established. We have also developed a receiver cryostat. We are able to maintain a sufficient cold status for observations on the optical configuration. We plan to start commissioning the system by observing CMB in Japan in 2015–2016. We will then deploy GroundBIRD in the Canary Islands for further scientific observations.
KeywordsCosmic microwave background Polarization Microwave kinetic inductance detector
This work is supported by Grants-in-Aid for Scientific Research from The Ministry of Education, Culture, Sports, Science, and Technology, Japan (KAKENHI Grant Nos. 23684017, 25610064, 26105519, 26247045, 14J10972, 15H05448, and 15H05743), the Center for the Promotion of Integrated Sciences (CPIS) of SOKENDAI, the FY 2012 Joint Development Research on an Open Application Basis program of the NAOJ, Research Grants in the Natural Sciences from the Mitsubishi Foundation, and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2013R1A1A2004972).