Exploring the primordial Universe with QUBIC

Transcription

1 Exploring the primordial Universe with the Q U Bolometric Interferometer for Cosmology J.-Ch. Hamilton, APC, Paris, France (CNRS, IN2P3, Université Paris-Diderot)

2 Expected difficulties in the B-Modes Quest Sensitivity : B polarization is at best 10 times weaker than E Amplitude could be very small... 1 year of Planck is ~ S/N=1 for T/S=0.01 A dedicated space mission might not be for tomorrow. Foregrounds : Need to remove them accurately (can t just mask) Multiwavelength instruments Observe an ultra-clean region can t be too small as primordial B modes are mainly on large scales Systematic effects : Instrument induces leakage of T into E and B (and T>>E>>B) Cross-polarization, beams and ground pickup are major issues Need for accurate polarization modulation and detailed knowledge of instrument properties

3 Possible instruments Imagers with bolometers: No doubt they are nice detectors for CMB: - wide band - low noise Especially true for a satellite (small background) Interferometers: Long history in CMB - CMB anisotropies in the late 90s (CAT: 1 st detection of subdegrees anisotropies, VSA) - CMB polarization 1 st detection (DASI, CBI) Clean systematics: - No telescope (lower ground-pickup & cross-polarization) - Angular resolution set by receivers geometry (well known) Technology used so far - Antennas + HEMTs : higher noise - Correlators : hard to scale to large #channels Can these two nice devices be combined? Bolometric Interferometry C l FT correlator C l Visibilites V(u,v) FT P. Timbie Imager Interferometer l

4 Possible instruments Imagers with bolometers: No doubt they are nice detectors for CMB: - wide band - low noise Especially true for a satellite (small background) Interferometers: Long history in CMB - CMB anisotropies in the late 90s (CAT: 1 st detection of subdegrees anisotropies, VSA) - CMB polarization 1 st detection (DASI, CBI) Clean systematics: - No telescope (lower ground-pickup & cross-polarization) - Angular resolution set by receivers geometry (well known) Technology used so far - Antennas + HEMTs : higher noise - Correlators : hard to scale to large #channels Can these two nice devices be combined? Bolometric Interferometry Good sensitivity Good control of systematics Both

5 The collaboration APC Paris, France IAS Orsay, France CSNSM Orsay, France IRAP Toulouse, France Institut Néel, Grenoble, France Maynooth University, Ireland Università di Milano-Bicocca, Italy Università degli studi, Milano, Italy Università La Sapienza, Roma, Italy University of Manchester, UK Richmond University, USA Brown University, USA University of Wisconsin, USA + China (IHEP & PMO) about to join arxiv: ~ Astroparticle Physics 34 (2011)

6 design 45 cm Sky 0 GHz 20x20 horns14 deg. FWHM <1K Cold box Filters Half-wave plate Primary horns Switches Secondary horns Y polarization bolometer array (~30x30) Polarizing grid <1K X polarization bolometer array (~30x30) 300 mk Cryostat

7 design 45 cm Sky 0 GHz 20x20 horns14 deg. FWHM <1K Cold box Filters Half-wave plate Primary horns Switches Secondary horns Y polarization bolometer array (~30x30) Polarizing grid <1K X polarization bolometer array (~30x30) 300 mk Cryostat

8 design 45 cm Sky 0 GHz 20x20 horns14 deg. FWHM <1K Cold box Filters Half-wave plate Primary horns Switches Secondary horns Y polarization bolometer array (~30x30) Polarizing grid <1K X polarization bolometer array (~30x30) 300 mk Cryostat

9 design 45 cm Sky 1 horn open 0 GHz 20x20 horns14 deg. FWHM Filters Half-wave plate <1K Cold box Primary horns Switches Secondary horns Y polarization bolometer array (~30x30) Polarizing grid <1K 300 mk Cryostat X polarization bolometer array (~30x30)

10 design 45 cm Sky BS 10 1 horn open BS 21 1 baseline BS 54 1 baseline Resulting BS 5 signal 1 baseline GHz x20 horns14 deg. FWHM BS 21 Y polarization bolometer 0 array (~30x30) Resulting BS signal 5 <1K BS 2 Resulting signal Polarizing grid 0 <1K -5 BS 2 Cold box Resulting signal Filters Half-wave plate Primary horns Switches Secondary horns total signal (all baselines) X polarization bolometer array (~30x30) mk Cryostat

11 design fringes successfuly observed in 2009 with MBI-4 [Timbie et al. 2006] 45 cm Sky BS 10 1 horn open MBI-4 data 2009 campaign (PBO- BS 21 Wisc.) 1 baseline BS 1 & baseline 1 & 3 Resulting BS 5 signal 1 baseline GHz x20 horns14 deg. FWHM BS 21 Y polarization bolometer 0 array (~30x30) Resulting BS signal 5 <1K BS 2 Resulting signal Polarizing grid 0 <1K -5 BS 2 Cold box Resulting signal Filters Half-wave plate Primary horns Switches Secondary horns & total signal (all baselines) 2 & X polarization bolometer array (~30x30) mk Cryostat

12 B.I. = Synthesized imager Primary horns array Synthesized beam Window: 403.0mm - Nhorns= Horn position in mm u Horn position in mm 0 GHz, 20x20 horns, 14 deg. FWHM, D=1.2 cm Synthesized beam used to scan the sky as with an imager

13 B.I. = Synthesized imager Primary horns array Synthesized beam Window: 403.0mm - Nhorns= Horn position in mm u Horn position in mm 0 GHz, 20x20 horns, 14 deg. FWHM, D=1.2 cm Synthesized beam used to scan the sky as with an imager

14 B.I. = Synthesized imager Primary horns array Synthesized beam Window: 403.0mm - Nhorns= Horn position in mm u Horn position in mm 0 GHz, 20x20 horns, 14 deg. FWHM, D=1.2 cm Synthesized beam used to scan the sky as with an imager

15 B.I. = Synthesized imager Primary horns array Synthesized beam Window: 403.0mm - Nhorns= (including detector finite size and 30% BW) Horn position in mm FWHM 0.54 deg. 8.5 deg. 2 u Horn position in mm 0 GHz, 20x20 horns, 14 deg. FWHM, D=1.2 cm Synthesized beam used to scan the sky as with an imager

16 Map Making ~ as an imager Scan the sky with synthesized beam Az. scans at constant elevation following a single field Phi rotation around optical axis Reproject data on the sky ˆT = A t N 1 A 1 A t N 1 d Synthesized beam has multiple peaks Usual map making assumes A has a single non zero element in each column - Does not lead to good results Improved method with better beam approximation - Sparse matrices helps fast convergence of CG - First results on simulations are promising [Pierre APC]

17 Map Making ~ as an imager Scan the sky with synthesized beam Az. scans at constant elevation following a single field Phi rotation around optical axis Reproject data on the sky ˆT = A t N 1 A 1 A t N 1 d Synthesized beam has multiple peaks Usual map making assumes A has a single non zero element in each column - Does not lead to good results Improved method with better beam approximation - Sparse matrices helps fast convergence of CG - First results on simulations are promising [Pierre APC]

18 Map Making ~ as an imager Scan the sky with synthesized beam Az. scans at constant elevation following a single field Phi rotation around optical axis Reproject data on the sky ˆT = A t N 1 A 1 A t N 1 d Synthesized beam has multiple peaks Usual map making assumes A has a single non zero element in each column - Does not lead to good results Improved method with better beam approximation - Sparse matrices helps fast convergence of CG - First results on simulations are promising [Pierre APC]

19 Site: Dome C, Antarctica

20 Site: Dome C, Antarctica Great landscape

21 Site: Dome C, Antarctica Great landscape Healthy weather

22 Site: Dome C, Antarctica 0PWV (mm) Great Courtesy L. Valenziano landscape Great for CMB observations Healthy weather

23 Detection Chain TES + + SiGe ASIC Mux CSNSM: Stefanos Marnieros APC: Michel Piat IRAP: Ludovic Montier 2 arrays of 992 NbSi TES Each array : 4x248 elements 100 mk bath (dilution) 3 mm size NEP ~ W.Hz -1/2 time constant ~ 10 ms Multiplexed Readout pre-amplifier+mux - 32:1 multiplexing SiGe ASIC (amp+mux) - 4:1 multiplexing 128 channels / ASIC Low noise: ~200 pv.hz -1/2 low power: ~ few mw

24 Total : Wafer: 3" Bolos: 3mm + 0.2mm Total : Bolos: 3mm + 0.2mm 3" Wafer: Detection Chain TES + + SiGe ASIC Mux CSNSM: Stefanos Marnieros APC: Michel Piat IRAP: Ludovic Montier 2 arrays of 992 NbSi TES Each array : 4x248 elements 100 mk bath (dilution) 3 mm size NEP ~ W.Hz -1/2 time constant ~ 10 ms Multiplexed Readout pre-amplifier+mux - 32:1 multiplexing SiGe ASIC (amp+mux) - 4:1 multiplexing 128 channels / ASIC Low noise: ~200 pv.hz -1/2 low power: ~ few mw Total : 257 Wafer: 3" Bolos: 3mm + 0.2mm Wafer: 3" Bolos: 3mm + 0.2mm Total : 257

25 Total : Wafer: 3" Bolos: 3mm + 0.2mm Total : Bolos: 3mm + 0.2mm 3" Wafer: Detection Chain TES + + SiGe ASIC Mux CSNSM: Stefanos Marnieros APC: Michel Piat IRAP: Ludovic Montier 2 arrays of 992 NbSi TES Each array : 4x248 elements 100 mk bath (dilution) 3 mm size NEP ~ W.Hz -1/2 time constant ~ 10 ms Multiplexed Readout pre-amplifier+mux - 32:1 multiplexing SiGe ASIC (amp+mux) - 4:1 multiplexing 128 channels / ASIC Low noise: ~200 pv.hz -1/2 low power: ~ few mw Total : 257 Wafer: 3" Bolos: 3mm + 0.2mm Wafer: 3" Bolos: 3mm + 0.2mm Total : 257

26 Total : Wafer: 3" Bolos: 3mm + 0.2mm Total : Bolos: 3mm + 0.2mm 3" Wafer: Detection Chain TES + + SiGe ASIC Mux CSNSM: Stefanos Marnieros APC: Michel Piat IRAP: Ludovic Montier 2 arrays of 992 NbSi TES Each array : 4x248 elements 100 mk bath (dilution) 3 mm size NEP ~ W.Hz -1/2 time constant ~ 10 ms Multiplexed Readout pre-amplifier+mux - 32:1 multiplexing SiGe ASIC (amp+mux) - 4:1 multiplexing 128 channels / ASIC Low noise: ~200 pv.hz -1/2 low power: ~ few mw NEW: 1st 248 TES batch: Currently under tests Total : 257 Wafer: 3" Bolos: 3mm + 0.2mm Wafer: 3" Bolos: 3mm + 0.2mm Total : 257

27 Cryostat Designed in Roma P. de Bernardis / S. Masi 45 cm window Stack (~20 cm) of zotefoam layers 1st stage: : Pulse-Tube Filters, horns, switches, HWP, 1st mirror 2nd stage: 300 mk: 7 He evaporation cooler 2nd mirror, polarizing grid, detectors

28 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode

29 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode

30 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode

31 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode

32 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode RMS before RMS after Horns location Individual beams TES Intercalibration pointing error, instrument effective Jones matrix......

33 Systematics: Self-Calibration Unique possibility to handle systematic errors Use horn array redundancy to calibrate systematics - In a perfect instrument redundant baselines should see the same signal - Differences due to systematics - Allow to fit systematics with an external source on the field Unique specificity of Bolometric Interferometry [Bigot-Sazy et al., A&A 2012, arxiv: ] Example: exact horns locations (figure exagerated ) Redundant baselines : same Fourier Mode Jones Matrix residual error Horns location Individual beams TES Intercalibration Accuracy on systematics estimations is only limited by statistics pointing error, instrument effective 10-6 Jones matrix RMS before RMS after Time spent on each baseline (s) 6

34 Self-Calibration results l(l+1)cl/2π) [µk 2 ] C BB for r=0.05 ( Target) range C EE leakage without self-calibration C EE leakage with self-calibration (2.5% of observation time) Expected signal (r=0.05) initial E B leakage Self-Calibration residual E B leakage ell [Bigot-Sazy et al., A&A 2012, arxiv: ]

35 timeline 2012: Partially funded by french ANR 2013: Construction started for the 1st module 400 horns - 0 GHz TES bolometers 2014: Integration at APC, Paris 20: First light at Dôme C, Antarctica Data taking : one to two years (incl. winter) with one module 20...: Full construction 6 modules at 90, 0 and 220 GHz

36 tensor/scalar ratio sensitivity : l= years - NET = 200µK.Hz -1/2 90% C.L. upper limit on Tensor to scalar ratio r WMAP7y Planck TT + WMAP Pol + HighL + BAO 1 Module 6 Modules 0.001

37 Summary is a novel instrumental concept Bolometric Interferometer optimized to handle systematics (self-calibration) - is an synthesized imager observing a selected range of spatial frequencies that can be accurately calibrated Dedicated to CMB polarimetry and inflationary physics High sensitivity with ~2000 TES bolometers Located at Dome C, Antarctica Target : - First module (0 GHz): r < 0.05 at 90% C.L. (first light ~ late 20) - Six modules (90, 0, 220 GHz) : r < 0.01 at 90% C.L.

38 Thank you