LiteBIRD: Lite satellite for the study of B-mode polarization and Inflation from cosmic microwave background radiation detection

H. Ishino, on behalf of the LiteBIRD team

 We present the current status of LiteBIRD, a next generation satellite for the detection of B-mode polarization of the Cosmic Microwave Background (CMB). It aims to measure the tensor-to-scalar ratio with 0.002 sensitivity at the 95% confidence level that will offer us crucial test criteria for major inflation models. LiteBIRD plans to conduct an all-sky survey at the sun-earth second Lagrange point with an angular resolution of about 0.5 degrees to measure the B-mode power spectrum in the multipole range of ell=2 to 200 in its three years of operation. Main systems for the measurement are optical system, focal plane detector arrays and polarization modulators. The optical system contains two telescopes covering the frequency range from 40 to 402 GHz to remove foreground components with a level of less than 1%. Two arrays consisting of 2,622 superconducting transition edge sensors on the focal plane provide a sensitivity of 2.5 uK-arcmin. Each telescope has its own continuous rotating half wave plate that modulates the polarization of incoming photons to mitigate 1/f noise and systematics. We use two telescopes to relax the requirements imposed on the half wave plate specifications in terms of bandwidth and anti-reflection. The LiteBIRD mission has been down-selected as a candidate of the JAXA Strategic Large Missions and is in the Phase-A1. The LiteBIRD US team’s proposal for the NASA Missions of Opportunity has also been down-selected for the Phase-A study to design the focal plane detectors and the ADR. We target to launch the satellite in early 2020s.