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Context: Planck & B-pol Polarized foregrounds The PILOT experiment

PILOT balloon experiment. J.-Ph. Bernard CESR Toulouse. Context: Planck & B-pol Polarized foregrounds The PILOT experiment. J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006. PILOT:Science Objectives. Polarized Instrument for Long-Wavelength Observations of the Tenuous ISM.

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Context: Planck & B-pol Polarized foregrounds The PILOT experiment

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  1. PILOT balloon experiment J.-Ph. Bernard CESR Toulouse • Context: Planck & B-pol • Polarized foregrounds • The PILOT experiment J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  2. PILOT:Science Objectives Polarized Instrument for Long-WavelengthObservations of the Tenuous ISM • Observe the linear polarization of dust emission in order to :- Reveal the structure of the magnetic fieldwhich controles the structuration of theInterstellar medium and the collapse leading to the formation of new stars- The nature of dust grainsthrough their geometric and magnetic properties • Understand the polarized foreground for future CMB polarized missionsAn accurate subtraction of this foreground emission will require a deep understandingof its origin. It also requires detection of dust polarization in faint diffuse cirrus clouds. These objectives require high sensitivity and fast mappingand therefore the use of bolometer filled arrays. http://pilot.cesr.fr J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  3. PILOT:Consortium France:CESR Toulouse (J.P. Bernard, C. Marty)IAS Orsay (B. Leriche)CEA Saclay (L. Rodriguez)CNES Toulouse (Div ballon)Europe: ESTEC Netherlands: (J. Tauber, G. Pilbrat)Cardiff U. UK (M. Griffin, P. Hargrave)Manchester U. UK (B. Maffei)Roma Italy (S. Masi, P. deBernardis) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  4. PILOT:Description Azimuth scanning Photometer Stellar sensor Elevationchange Primary miror CNES gondola J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  5. Characteristics Instantaneous FOV: 46'*23' J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  6. Planck: polarized Planck: unpolarized FIR/submm Planck Planck should allow to detect l-variations of the dust polarization(at 3-s every 1° below Av=0.5 mag). Detecting more precisely smaller variations toward more diffuse clouds may require using a polarized instrument at higher frequency like PILOT J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  7. PILOT vs Planck l-coverage Planck: polarized Planck: unpolarized PILOT J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  8. PILOT:Description • Gondola : « standard » CNES (LPMA/IASI), about 500kg Rotation in azimut allowing scans on the skyTelescope : = 1m, off-axis Gregorian. Angular resolution = 3’ @ 550 mm • Stellar sensor : large format CCD. Scanning sky at 1.5°/s. hopefuly day/night. • Photometer : • 2 photometric chanels @ 240 mm and 550 mm • Detectors cooled down to 300 mK J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  9. PILOT: Optics • Telescope:-off-axis parabolic primary mirror (M1) • off-axis ellipsoid secondary mirror (M2) • Mitsugushi-Dragone config. • Reimaging Optics:-Two lenses (L1 & L2). • Lyot stop (L). • Half-wave plate (WP). • Telecentric objective config. • WP and L next to a pupil (image of M1) of the optics. • Polar analysis grid (G) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  10. PILOT:Detectors 0.3 K J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  11. PILOT:Detectors J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  12. PILOT:Detectors Interconnection Circuit Thermometer Silicon Grid + Absorber Indium Bumps Reflector Bolometer arrays developped by CEA/LETI for Herschel/PACSmultiplexed readout NEP = 2 10-16 W/Hz-1/2 16*16 pixels PILOT will have a total of2048 individual bolometers !! (to be compared with less than 100 for previous instruments) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  13. Polarization Measurement Principle of the polarization measurement with PILOT input linear polarization Bi-refringent material1/2 wave plate Reflection detector Grid analyzer Transmission detector J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  14. Polarization Measurement Principle of the polarization measurement with PILOT input linear polarization Bi-refringent material1/2 wave plate Reflection detector Grid analyzer Transmission detector J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  15. Polarization Measurement Principle of the polarization measurement with PILOT • Most existing experiments rotate the HWP at constant velocity and detect modulated signal on detectors. • For PILOT, we change HWP positions by discrete steps because: • 1/ we do not want to modulate even a tiny fraction of the background • (background is 104 times the scientific signal, ie 106 times the polarization) • 2/ sky mapping while spinning would be too fast for the available detectors. J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  16. Polarization Measurement J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  17. PILOT: scanning strategy 240 mm 550 mm Elevation Azimuth J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  18. Polarization Measurement For one position w of the waveplate, one measures : At least 2 positions are needed to measure I, Q, U Q,U derived from differences I measured from average (Transmission array) (Reflection array) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  19. Polarization Measurement Wave-plate angle "Paralactic" angle Instrumental rotation J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  20. PILOT:Calibration Source No unpolarized calibration source on sky Internal calibration source= Spare of the Herschel SPIRE calibration source - Very accurate repeatability- Fast on/off switch- Low consumption- Used to calibrate Response flat-field J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  21. PILOT: Sensitivity Results : Galactic plane 30 mn observations @ 240 mm, 250 /hr Input Intensity Recovered Intensity Polarization (%) Max=6%(Red) Min=4%(blue) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  22. Simulations Max=3%(Rouge) Min=8%(bleu) Results : Cirrus (Av=2 mag) 1hr observations @ 240 mm, 16 /hr Input Intensity Recovered Intensity Polarization (%) J.-Ph. Bernard, PILOT CNES review, Toulouse, March 13th 2006

  23. Mission Planning • Objective on astronomical targets- Galactic plane survey- Deep field on cirrus clouds- Large and Small Magellanic Clouds • Source visibility requires combination of 3 flights from different launch sites (different latitudes) • Preliminary study with:- Kiruna - Sweeden (lat = 60°, flight #1, winter 2008) • Trapani - Italy (lat=38°, flight#2, summer 2009) • Alice-Spring or Sao-Jose-Dos Campos- Brazil (lat = -23°, flight#3, spring 2010) • Simulations performed with realistic parameters:- mapping speed: 300°2/h- vscan=24'/s- scan amplitude=20° • Observational constraints:- 20° < elevation < 60°- night-time observations only J.-Ph. Bernard, PILOT CNES review, Toulouse, March 13th 2006

  24. Mission Planning Kiruna Trapani AliceSpring Sao-Jose ~ 90% of the Galactic plane is surveyed within a 20- 25 hrs total integration time 12 to 16 hrs left for others tagets (Cirrus, Magellanic clouds, calibration…) We insist on the fact that it would be much more convenient and safe for the scientific return of each flight to be able to observe during day-time, even though it is not formally required. -> a day-operating stellar sensor would be a goal to reach for the two last flights. J.-Ph. Bernard, PILOT CNES review, Toulouse, March 13th 2006

  25. The END • PILOT will attempt at measuring the linear polarization from dust emission in our Galaxy to very high accuracy levels at high frequencies • The goal is to understand the physics of dust polarization, to ultimately help with component separation for future cosmology missions • PILOT is a test-bed for the use of compact multiplexed bolometer arrays for polarization measurements • PILOT is funded by CNES. Detailed definition is ending and realization of the instrument is starting. • First flight expected in end-2008 (Kiruna) PILOT http://pilot.cesr.fr J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  26. The END • PILOT will attempt at measuring the linear polarization from dust emission in our Galaxy to very high accuracy levels at high frequencies • The goal is to understand the physics of dust polarization, to ultimately help with component separation for future cosmology missions • PILOT is a test-bed for the use of compact multiplexed bolometer arrays for polarization measurements • PILOT is funded by CNES. Detailed definition is ending and realization of the instrument is starting. • First flight expected in end-2008 (Kiruna) PILOT PILOT is the pilot fish Future CMB-pol mission ? http://pilot.cesr.fr J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15th 2006

  27. CMB Anisotropy/Polarization map from B2K (2003)

  28. BOOMERanG-FG • We plan to re-fly B03 with an upgraded forcal plane, to go after foreground cirrus dust polarization. • This information is essential for all the planned B-modes experiments (e.g. BICEP, Dome-C etc.) and is very difficult to measure from ground. • The BOOMERanG optics can host an array of >100 PSB at >350 GHz.

  29. BOOMERanG-03 140 GHz PSB 240 GHz 340 GHz BOOMERanG-FG 140 GHz PSB 340 GHz PSB Frequency range complementary to PILOT (higher f. J.F. Bernard, Toulouse)

  30. From C. Lawrence, PoS (CMB2006) 012

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