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Groundbird Experiment an Experiment for CMB PolarizaOn Measurements at a Large Angular Scale from the Ground

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Groundbird Experiment an Experiment for CMB Polariza�On Measurements at a Large Angular Scale from the Ground GroundBIRD Experiment an experiment for CMB polariza2on measurements at a large angular scale from the ground Osamu Tajima (KEK) The GroundBIRD group GroundBIRD’s target Probing Inflationary Universe B-modes in CMB polarization is Primordial its smoking-gun signature !! Gravitational Foregrounds Now Waves CMB First star Begin of the Universe Inflation Big Bang Dark age Recombination Re-ionization Galaxy formation Age 10-36 sec 380 Kyr 1 Myr 13.8 Gyr 2 Now Foregrounds Foregrounds Now First starCMB CMBFirst star Begin of the Begin of the Universe Universe Inflation Inflation Dark age Dark age Reionization RecombinationRecombination Reionization 10 Chaotic p=1 ) Chaotic p=0.2 2 SSB (N =47~62) 1 e -1 (uK 10 π -2 /2 10 r = 0.10 l 10-3 10-4 r = 0.01 l(l+1)C -5 Two bumps structure is expected 10 10 100 1000 3 Multipole l (=180o/θ) Primordial B-modes Natural to have an experimental target:! " "spectrum measurements, ! " "i.e. simultaneous measurements of two bumps Model predictions 10 ) Chaotic p=1 2 Chaotic p=0.2 SSB (N =47~62) 1 e (uK 10-1 π /2 -2 l 10 r = 0.10 10-3 -4 r = 0.01 l(l+1)C 10 10-5 10 100 1000 Multipole l (=180o/θ) 4 Advantage of spectrum measurements w.r.t. physics Spectrum shape allows us to distinguish ! "whether the inflation model is ! "``standard’’ or ``beyond the standard’’! Just an example… At the case of Big Bounce model by exotic quantum-gravitational effects J. Grain, A. Barrau, T. Cailleteau, J. Mielczarek, Phys.Rev.D82:123520 (2010). ``Beyond the standard’’ is also big discovery !!! 5 ""(whereas it may be dark horse targets … ) Advantage of spectrum measurements 10° 1° 0.1° Model predic+ons of Primordial B-modes 10 Chaotic p=1 E-modes ) Chaotic p=0.2 2 SSB (N =47~62) 1 e -1 Lensing B-modes (uK 10 π -2 /2 10 r = 0.10 l Primordial B-modes 10-3 -4 r = 0.01 l(l+1)C 10 10-5 10 100 1000 Mul4pole l Lensing B-modes become dominant at a small angular scale 6 Advantage of spectrum measurements Expansion of scan range is promising solu2on 10° 1° 0.1° Model predic+ons of Primordial B-modes Model predic+ons of ) Primordial B-modes 2 10 Chaotic p=1 aims to measure B-modes E-modes ) Chaotic p=0.2 2 1 SSB (N =47~62) spectrum shape (uK e π -1 Lensing B-modes (uK 10 /2 π l GroundBIRD C -2 /2 10 r = 0.10 l Primordial B-modes 10-3 Primordial B-modes l(l+1) Lensing B-modes -4 r = 0.01 l(l+1)C 10 10-5 10 Mul4pole l 100 1000 Mul4pole l Lensing B-modes become dominant at a small angular scale Large angular scale is free from the lensing B-modes 7 GroundBIRD - overview Plan to have test observa+on in CMB (FOV ±10°) Japan (early 2014). Then, instruments will be moved to Chile for science observa+ons Cold op2cs at 4K Single scan paern at Chile Mizuguchi-Dragone Dual reflector Focal plane (0.5° at 150GHz) MKIDs at 0.25 K High speed rotation Rotaon stage scan at 20 RPM! No decelera2on ! To be 1/f noise free !8 GroundBIRD’s scan strategy Very large observing area GroundBIRD: 30% of full sky Other ground-based (e.g. QUIET ~3%) Effec4vely, it is similar to the low earth orbit (LEO) scan of the satellite experiments. GroundBIRD implements “Super-LEO” scan. 9 Eliminaon of 1/f noise effects limits the scan range by the scan modulaon Usual le-right azimuth scan GroundBIRD’s high-speed (average scan speed: 3o/sec) rotaLon scan (20 rpm) 60o e.g., FOV 10o, EL 70o o 60 Fast scan is the most promising way to eliminate 1/f noise effects GroundBIRD Loss factor : A Detector’s 1/f noise A x Cl GroundBIRD maintains Δ fknee = 100 mHz No loss A = 1 at l = 6 1/f-noise-free condion No 1/f noise (even w/o con4nuous rotaon of HWP) Loss factor : A 10 Average scan speed Another 1/f noise source Effects of atmospheric fluctuaon Typical atmospheric fknee is ≈ Hz at Atacama Desert in Chile (5,000 m), whereas it is not polarized in our oBserva2on frequency Bands Simulation assuming atmospheric fknee = 10 Hz, detector’s intrinsic fknee = 100 mHz! 10% gain diff. Responses in Stokes’ Q Fourier scape Pair gain diff. induces the residual effects in polarizaon response. Calibra+on is GB’s scan freq. (0.3 Hz) important ! 11 Calibraon during CMB observaon Good demonstration! by QUIET & ABS! Difference btw sky (10K) and sparse wires (300K) makes uniform polarizaon signals Rotation in constant speed Ideal modulation O. Tajima et al. , J. Low Temp. Phys., 167, 936 (2012). 12 For the case of GroundBIRD Responses for each antenna (simulaon) 1/2 Input: Atm. fknee = 10 Hz, detector’s fknee = 100 mHz & NET = 300 uKs , ! and 10% of pair gain diff. Response as a func4on of 4me Response in Fourier scape Calibraon cos2θ response signal (1/2 of fscan) Calibraon 2 sin θ response signal (1/2 of fscan) Before / After! the calibration! sin2θ response 5 min. of data precisely calibrates the pair gain difference. 13 Calibraon also makes good syst. error control Precision of calibraon with 5 min. data T = 0.5 K! calibration Temperature anisotropy (TT) Tcalibration = 1.0 K BeYer precision with lower fknee of atmospheric fluctua2on ) 2 Systematic bias induced by! (uK π TT x pair gain diff. (0.1%) Atmospheric f at Atacama Dessert/2 knee l Prospects that we can trace B-modes ( r = 0.01) pair gain difference with 0.1% precision with the con2nuous l(l+1)C itera2on in every 5 min. Systema2c errors can Be controlled Below the level of r = 0.01 Mul4pole l 14 Systemac error control (cont.) Temperature anisotropy (TT) Angle caliBra2on also does well ) 2 Alignment of wire Systematic bias induced by! direc+on should be (uK precise π TT x pair gain diff. (0.1%) /2 EB mixing l with 0.1o of B-modes ( r = 0.01) angle precision l(l+1)C Demonstration of this calibration strategy is one of the important Mul4poletargets lof test observation 15 Status of the development Development of MKIDs with Developments of each all Japan technologies component in parallel RIKEN, NAOJ, Okayama, and KEK MKIDs See posters Rotaon stage Prototype Mirror Rotary joints for electricity and helium gas 16 Rotatable Cryocooling System Cryocooler Patent pending Vacuum chamBer Rev. Scien. Instru. 84, 055116 (2013). Wireless-LAN Scan speed x40 !! Real 4me monitoring RotaLon stage Rotary joints QUIET’s scan: ~3deg/sec Simultaneous circulaon of High pressure hoses electricity and helium gas !! (connected to the compressor) Weights on the stage for this test (~100 kg) Focal plane design High frequency detectors are useful to understand foregrounds; i.e., dust 145! 145! GHz GHz 145! 220! 145! GHz GHz GHz 145! 145! GHz GHz Design by Karatsu & NiMa (NAOJ). Please visit poster P-16 Design array sensi4vity ~ 10 uKs1/2 Posters about MKIDs • Devise R&D! P-16: K. Karatsu, ``Development of MKID camera for future ground-based CMB observaons’’ P-17: T. Noguchi, ``Influence of quasipar4cles in the intra-gap states on the noise of a MKID’’ Student P-19: H. WatanaBe, ``Hybrid MKIDs with ground-side deposi4on - A novel method for microwave detec4on with a resonator separated from an antenna’’ P-20: M. Yoshida, ``The development of MKIDs and its low nois amplifier for CMB experiment’’ • Readout system w/ common mode noise suppression! P-21: Y. Kibe, ``Low noise readout system for MKIDs with frequency-domain mul4plexing technique towards applicaon of CMB observaon’’ Summary • GroundBIRD aims to measure inflationary B-modes ``spectrum’’ from the ground! – Provides unique physics studies! • Whether Standard or Beyond-standard inflation model! • Free from lensing B-mode! • Unique technologies realize the unique physics! – High-speed rotation scan ! • Very large observing fields (fsky ~30%)New! idea is challenge !! • 1/f-noise-free conditions! Demonstration is important – Continuous calibration using sparse wires! • Good systematic error control & eliminating the effects of atm. fluctuation! – Cold optics conditions, i.e., instruments are compact! • Plan to have test observation in Japan in 2014.! • Then, we will move to Chile for scientific observations! 20 Near term plan .
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