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

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

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

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

6. FIR/submm Planck Planck should allow to detect -variations of the dust polarization (at 3-  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 Planck: unpolarized Planck: polarized J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006

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

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

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

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

12. Bolometer arrays developped by CEA/LETI for Herschel/PACS multiplexed readout NEP = 2 10 -16 W/Hz -1/2 16*16 pixels PILOT:Detectors Interconnection Circuit Thermometer Silicon Grid + Absorber Reflector Indium Bumps J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006 PILOT will have a total of 2048 individual bolometers !! (to be compared with less than 100 for previous instruments)

13. Principle of the polarization measurement with PILOT Bi-refringent material 1/2 wave plate input linear polarization Grid analyzer Transmission detector Reflection detector Polarization Measurement J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006

14. Principle of the polarization measurement with PILOT input linear polarization Grid analyzer Transmission detector Reflection detector Polarization Measurement J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006 Bi-refringent material 1/2 wave plate

15. 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 10 4 times the scientific signal, ie 10 6 times the polarization) 2/ sky mapping while spinning would be too fast for the available detectors. Polarization Measurement J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006

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

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

18. For one position  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) Polarization Measurement J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006

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

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

22. Simulations Results : Cirrus (Av=2 mag) 1hr observations @ 240  m, 16 /hr Input IntensityRecovered IntensityPolarization (%) Max=3% (Rouge) Min=8% (bleu) 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. ~ 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. Kiruna TrapaniAliceSpring Sao-Jose Mission Planning J.-Ph. Bernard, PILOT CNES review, Toulouse, March 13th 2006

25. The END PILOT http://pilot.cesr.fr 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) J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006

26. The END PILOT is the pilot fish Future CMB-pol mission ? PILOT http://pilot.cesr.fr J.-Ph. Bernard, CNES CCT, Toulouse, Nov. 15 th 2006 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)

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

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