Lite BIRD Lite light Satellite for the studies

Lite. BIRDとは Lite (light) Satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection 2008年 9月JAXA小型科学衛星WGとして承認 3

Search for r=O(0. 01) is well motivated Search for r=O(0. 001) is comprehensive Pagano-Cooray-Melchiorri-Kamionkowski 2007 Current upper limit r = T/S (テンソル・スカラー比） 重力波の相対的な大きさ) inflation potential 6

Future prospects (Lite. BIRD) k Planc + IET a. R U Q r. Be a l Po D R I B e Lit Bモード：高まる発見への期待 7

Anti-Sun direction/Spin axis Bore sight Lenses Focal plane (TES又はSTJ） Half-wave plate ADR Radiation shields SQUIDs BUS unit JT/ST cooler head and compressor 赤外線衛星SPICAの方式 H. Sugita et al. Cryogenics 46 (2006) 149 10

多色焦点面検出器 ~30 cm lenslets 150 GHz-220 GHz diplexer TES 8 -band channelizer Development at UC Berkeley 11

Details on Power and Weight Guesstimation for near-earth option Mission part Weight (kg) Focal plane (detector, optics) 60 Mission part electronics (for detector) 20 Buffle, structure 40 Cryo-harness Power (W) 100 5 Sub-Kelvin refrigerator (ADR) 20 20 2 K refrigerator (JT+starling) 30 160 175 280 Weight (kg) Power (W) Structure, thermal control, etc. 50 30 Solar panel, electronics 30 20 Data acquisition, telemetry 20 60 Attitude control (AC) 50 100 150 210 325 490 Total for mission part Bus part Total for bus part Total (mission + bus) 12

Lite. BIRD Specifications Item Specification Lifetime Orbit AC > 2 years ( 5 years for the mission part) S-E L 2, or near-earth sun-synchronous orbit < 5 arcmin (i. e. < 1/10 x beamsize) Telemetry Weight Power 2 Mbps Mission part < 200 kg, total < 400 kg Mission part < 200 W, total < 500 W Cooling Focal plane Sensitivity Frequencies 100 m. K w/ SPICA-type JT+starling (+ He 3 sorption) + ADR Superconducting detector (TES or STJ) Total NET < 1 m. K s 90 GHz and 150 GHz with a sufficient number of pixels and angular resolution (< 1 deg), + 45 GHz + 300 GHz as much as possible Modulation Satellite rotation + more modulation methods 13

Powerful Duo Small satellite (Lite. BIRD) Ground-based superconducting CMB cameras 15

Backup 16

Experimental Cosmology Program at KEK l Precision Measurements of Cosmic Microwave Background (CMB) Polarization l Objective: B-mode polarization (“curl component”) l Science: Inflation, primordial gravitational wave, quantum gravity l Projects: 2007 08 09 phase I 10 11 12 13 14 15 16 17 18 19 phase II QUIET Polar. Bea. R QUIET+Polar. Bea. R Combined analysis Superconducting detector R&D (w/ RIKEN etc. ) Satellite WG (w/ JAXA etc. ) Preparation for a (small) satellite Launch before 2020 (Actual plans will depend on many factors)

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Experimental sensitivity Total sensitivity Rule of thumb CMB photon density ~ 400/cm 3 statistical fluctuation ~ 20/cm 3 fundamental CMB photon noise ~ 60 m. K sec best detector available now ~ 200 m. K sec need for ~1000 channels “Ideal” detector: noise << CMB photon noise Example: 1000 ch. 1 yr 60 m. K/ 10000. 5 / (3 107)0. 5 ~ 0. 35 n. K 22