Litebird Joint Study Group 211 Researchers from All Over the World

LiteBIRD Joint Study Group 211 researchers from all over the world

H. Sugai18, P. A. R. Ade71, Y. Akiba19,30, D. Alonso71, K. Arnold8, J. Aumont44, J. Austermann5, C. Baccigalupi60,52,58, A. J. Banday44, R. Banerji66, R. B. Barreiro68, S. Basak49,60, J. Beall5, S. Beckman7, M. Bersanelli63,55, J. Borrill3,7, F. Boulanger42, M. L. Brown75, M. Bucher38, A. Buzzelli62, E. Calabrese71, F. J. Casas68, A. Challinor74,72, V. Chan37, Y. Chinone7,18, J.-F. Cliche34, F. Columbro59,57, A. Cukierman7, D. Curtis7, P. Danto40, P. de Bernardis59,57, T. de Haan3, M. De Petris59,57, C. Dickinson75, M. Dobbs34, T. Dotani15, L. Duband39, A. Ducout18, S. Duff5, A. Duivenvoorden70, J.-M. Duval39, K. Ebisawa15, T. Elleflot8, H. Enokida13, H. K. Eriksen66, J. Errard38, T. Essinger-Hileman4, F. Finelli53, R. Flauger8, C. Franceschet63,55, U. Fuskeland66, K. Ganga38, J.-R. Gao65, R. Génova-Santos67,69, T. Ghigna76,18, A. Gomez40, M. L. Gradziel50, J. Grain42, F. Grupp48,47, A. Gruppuso53, J. E. Gudmundsson70, N. W. Halverson9, P. Hargrave71, T. Hasebe15, M. Hasegawa19,30, M. Hattori31, M. Hazumi19,15,18,30, S. Henrot-Versille45, D. Herranz68, C. Hill7,3, G. Hilton5, Y. Hirota13, E. Hivon41, R. Hlozek37, D.-T. Hoang1,77, J. Hubmayr5, K. Ichiki23, T. Iida18, H. Imada45, K. Ishimura32, H. Ishino26,19, G. C. Jaehnig9, M. Jones76, T. Kaga15, S. Kashima24, Y. Kataoka26, N. Katayama18, T. Kawasaki20, R. Keskitalo3, A. Kibayashi26, T. Kikuchi10, K. Kimura27, T. Kisner3, Y. Kobayashi16, N. Kogiso27, A. Kogut4, K. Kohri19, E. Komatsu46, K. Komatsu26, K. Konishi14, N. Krachmalnicoff60,52,58, C. L. Kuo6,2, N. Kurinsky6,2, A. Kushino22, M. Kuwata-Gonokami12, L. Lamagna59,57, M. Lattanzi54, A. T. Lee7,3, E. Linder3,7, B. Maffei42, D. Maino63,55, M. Maki19, A. Mangilli44, E. Martínez-González68, S. Masi59,57, R. Mathon44, T. Matsumura18, A. Mennella63,55, M. Migliaccio62,57, Y. Minami19, K. Mistuda15, D. Molinari61, L. Montier44, G. Morgante53, B. Mot44, Y. Murata15, J. A. Murphy50, M. Nagai24, R. Nagata19, S. Nakamura33, T. Namikawa74, P. Natoli61,54, S. Nerval37, T. Nishibori17, H. Nishino28, Y. Nomura29, F. Noviello71, C. O'Sullivan50, H. Ochi33, H. Ogawa27, H. Ogawa15, H. Ohsaki13, I. Ohta21, N. Okada15, N. Okada27, L. Pagano61,54, A. Paiella59,57, D. Paoletti53, G. Patanchon38, F. Piacentini59,57, G. Pisano71, G. Polenta51, D. Poletti60,52,58, T. Prouvé39, G. Puglisi6, D. Rambaud44, C. Raum7, S. Realini63,55, M. Remazeilles75, G. Roudil44, J. A. Rubiño-Martín67,69, M. Russell8, H. Sakurai12, Y. Sakurai18, M. Sandri53, G. Savini73, D. Scott36, Y. Sekimoto15,19,30, B. D. Sherwin74,72, K. Shinozaki17, M. Shiraishi25, P. Shirron4, G. Signorelli56, G. Smecher35, P. Spizzi40, S. L. Stever18, R. Stompor38, S. Sugiyama29, A. Suzuki3, J. Suzuki19, E. Switzer4, R. Takaku12, H. Takakura11, S. Takakura18, Y. Takeda15, A. Taylor76, E. Taylor7, Y. Terao13, K. L. Thompson6,2, B. Thorne76, M. Tomasi63,55, H. Tomida15, N. Trappe50, M. Tristram45, M. Tsuji25, M. Tsujimoto15, C. Tucker71, J. Ullom5, S. Uozumi26, S. Utsunomiya18, J. Van Lanen5, G. Vermeulen43, P. Vielva68, F. Villa53, M. Vissers5, N. Vittorio62, F. Voisin38, I. Walker71, N. Watanabe20, I. Wehus66, J. Weller48,47, B. Westbrook7, B. Winter73, E. Wollack4, R. Yamamoto10, N. Y. Yamasaki15, M. Yanagisawa26, T. Yoshida15, J. Yumoto12, M. Zannoni64,55, A. Zonca8 Aim of LiteBIRD Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection To test inflation scenario.

Existence of hot big bang established since discovery of Cosmic Microwave Background (CMB) in 1964.

Problems remain on uniformity, flatness, monopole. → Inflation proposed since 1980s.

LiteBIRD tests whether or not inflation really existed before hot big bang. Concepts of LiteBIRD Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection

1. Focused on CMB B-mode polarization by primordial gravitational waves produced by inflation, targeting both of: recombination era, with multipole moment 11≦l≦200 (17°≧q≧0.9°) reionization era, with 2≦l≦10 (90°≧q≧18°), optimizing the angular resolution as modest. Full success: dr < 1 x 10-3 (for r=0 (r=tensor-to-scalar ratio))

2. Warm launch without requirements of heavy vessels/tanks.

3. Use of multichroic detectors with ground-based heritage for the effective use of finite focal plane areas. 9090°° 99°° 0.90.9°°

B mode spiral pattern produced as well as E mode, the latter of which is also produced by density fluctuation.

gravitational lens

z~1000 z~10 Reionization Recombination

LB: 2≦l ≦200

Thomson Scattering 5 Gravitational wave http://background.uchicago.edu/~whu/ http://www.einstein-online.info/ intermediate/Polarization/polar1.html Advantages of Measurements from Space - Free from atmospheric effects - High sensitivity - Stability; Less systematic errors - No restrictions on observing-band selection

- No pickups from ground

Tropospheric ice clouds (Takakura et al. 2018) Scan strategy 11691 monthweekdayyearmonths minutes for case of Orbit: spin=0.1rpm precession~90min Sun-Earth L2 Lissajous

L2: Sun, Earth, Moon in almost same direction. → Easy to avoid facing to them. (0.05-0.1rpm) (But care should be taken on cosmic rays.)

7 Current status of LiteBIRD 2019 May ISAS/JAXA selected LiteBIRD as strategic large mission #2.

with design modification on cooling chain & focal planes: Adiabatic Demagnetization Refrigerators (ADRs) in series, removing JAXA-provided 1K JT.

2019 July LiteBIRD Kickoff Symposium @ ISAS/JAXA LiteBIRD general view 15 frequency bands for foreground cleaning: - Low Frequency Telescope (LFT): 34 to 161 GHz - Medium/High Frequency Telescope (MHFT): 166 to 448 GHz

Mass: 2.6 ton Electrical power: 3.0 kW Launch planned in 2027 FY Cooling chain

Current baseline: i) Down to 4.8 K: Sunshield and passive cooling with V grooves. 15K pulse tube coolers to strengthen this.

A 4K-JT with 2 double-ST precoolers. 100 mK Continuous ADR ii) From 4.8 K to 1.75 K: A parallel three-stage Adiabatic Demagnetization Refrigerator (ADR) for providing continuous cooling at 1.75K. iii) From 1.75 K to 100 mK: A multi-staged ADR with continuous cooling See J.-M. Duval, et al. in this workshop for details. at 300 mK and 100 mK. Telescopes, Focal planes & LiteBIRD Sensitivity Low Frequency Telescope Medium/High Frequency Telescope

See B. Mot, et al. for MHFT Crossed Dragone with crossed angle 90° 1

Multichroic pixels 1

15 frequency bands in total

Total sensitivity 2mK・arcmin

for Tmission = 3yrs (Vertical lines show CO/HCN line frequencies) 1 Table 2. LiteBIRD telescope parameters 1 Telescope Low Freq. Medium Freq. High Freq. Frequency 34-161 GHz 89-224 GHz 166-448 GHz Field of view 20°x 10° 28°diameter 28°diameter Aperture diameter 400 mm 300 mm 200 mm Angular resolution 70-24 arcmin 38-28 arcmin 29-18 arcmin Rotational HWP 46~83 rpm 39~70 rpm 61~110 rpm Number of detectors 1248 2074 1354 2 Transition-edge sensor (TES) developments

TES bolometers form a multichroic pixel. coupled with a silicon lenslet & a sinuous antenna See B. Westbrook, et al. for LFT&MFT. coupled with silicon platelet-based corrugated horn & OMT for HFT.

TES parameter optimization for LiteBIRD: Low saturation power detector for satellite environment. ∝ See G. Jaehnig, et al. Noise equivalent power √(Psat Tb), with Tc/Tb being optimized. (Psat: saturated power, Tc: transition temp., Tb: thermal bath temp.) Sensor impedance coupling to frequency domain multiplexer. Electro-thermal time constants controlled with additional heat capacity of PdAu. Transition-edge sensor (TES) developments

Cosmic-ray mitigation methods by reducing heat propagation: Palladium structures to absorb phonons. See Y. Minami, et al. Removing bulk silicon to block phonons.

Design of cryogenic testbed to study interaction between space-optimized detectors and other subsystems, See T. Ghigna, et al. especially polarization modulator unit consisting of magnetically rotating half wave plate. LFT Polarization modulator developments (As for MHFT PM developments, see B. Mot, et al.)

Cryogenic holder mechanism

Anti-reflection structure

Sapphire stacked Achromatic HWP

HWP holder Launch lock mechanism Rotation mechanism [SPIE 10708-12] Y. Sakurai et al. "Design and development of a polarization modulator unit based on a continuous rotating half-wave plate for LiteBIRD" [SPIE 10708-142] K. Komatsu et al. "Prototype design and evaluation of the nine-layer achromatic half-wave plate for the LiteBIRD low frequency telescope" Summary – LiteBIRD –

- Aiming at detecting signature of inflation. Whole sky observations of mm wavelength radio linear polarization, without atmospheric effects. → Detect specific spatial pattern of CMB polarization angle distribution produced by primordial gravitational waves.

- Selected as strategic large mission #2.

- Plan to launch in 2027 FY; Three-year observations at L2. LiteBIRD poster presentations

J.-M. Duval, et al. (108-157) “LiteBIRD cryogenic chain: 100 mK cooling with mechanical coolers and ADRs”

B. Mot, et al. (183-311) “The Medium and High Frequencies Telescopes of LiteBIRD”

B. Westbrook, et al. (226) “Detector fabrication development for the LiteBIRD satellite mission”

G. Jaehnig, et al. (75-227) “Development of Low-Frequency Space-Optimized TES Bolometer Arrays for LiteBIRD”

Y. Minami, et al. (74-272) “Irradiation tests of superconducting detectors and comparison with simulations”

T. Ghigna, et al. (99-257) “Design of a testbed for the study of system interference in space CMB polarimetry” Table 1. Updated basic parameters and baseline design for LiteBIRD 1 Mission category JAXA’s strategic large mission Launch vehicle H3-22L or equivalent Launch schedule 2027 FY Ground station JAXA’s ground stations (USC, GREAT) Observation period 3 years Uncertainty of tensor-to- dr < 1 x 10-3 scalar ratio r Multipole moment 2 ≦ l ≦ 200 Orbit Sun–Earth Lagrange point 2; Lissajous orbit Scan “Precession” angle 45°(10-2~-3 rpm); spin angle 50°(0.05~0.1 rpm) Pointing knowledge < 2.1 arcmin Cooling system Radiative cooling and mechanical refrigerators (Stirling and JT) without cryogen. Cool in space after launch. ADRs are used to cool the focal plane down to 100 mK Focal-plane detector Multi-chroic superconducting detector (TES) array with more than 4000 bolometers Sensitivity 2 mK・arcmin Observing frequencies 15 bands between 34 and 448 GHz Modulation Satellite spin and half-wave-plate modulation Data transfer 9.6 GByte / day Mass 2.6 ton Electrical power 3.0 kW 2