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( MEMS : MicroElectroMechanical Systems )

끝. MEMS Tracking Telescope for Extreme Energy Phenomena in Space I.H. Park (Ewha W. Univ.) thanks to B. Khrenov, G. Garipov, M. Klimov (Moscow State Univ.) S.W. Nam, M. Kim (Ewha W. Univ.). Optics and Aberrations Micro Mirrors Proposed Telescope using MEMS technology Summary and Plan.

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( MEMS : MicroElectroMechanical Systems )

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  1. 끝 MEMS Tracking Telescope for Extreme Energy Phenomena in SpaceI.H. Park (Ewha W. Univ.)thanks to B. Khrenov, G. Garipov, M. Klimov (Moscow State Univ.)S.W. Nam, M. Kim (Ewha W. Univ.) • Optics and Aberrations • Micro Mirrors • Proposed Telescope using MEMS technology • Summary and Plan ( MEMS : MicroElectroMechanical Systems ) Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  2. Presentations • 2003 Int. Cosmic Ray Conf. (ICRC Proceedings) • 2003 SpacePart Conf. (will be published in Nucl. Phys. B. PS) • 2004 COSPAR Conf. (submitted to Adv. Space Res.) Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  3. Detector ! Observe “from ABOVE” nitrogen fluorescence light Imaginative Idea (K.Greisen, J.Linsley …) Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  4. EECR Space Experiments EUSO at ISS European Module in 2010 Double Fresnel Lens + PMT + Electronics TUS/KLYPVE at satellite/ISS Russian Module in ~2010 Fresnel Mirror + PMT + Electronics • Complex lens optics • Wide FOV (60o) • Fixed size of pupil window • Simple mirror telescope • Large pupil window • Modules assembly in space • Limit in FOV • Larger FOV requires shorter Focal Distance • Butaberrations and distortions become larger Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  5. EUSOExtreme Universe Space Observatory for EHECR Observations Aperture ~ 105 km2 sr Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  6. First Order Optics (Paraxial Optics) Lens maker’s formula Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  7. Lens maker’s formula 3rd order Paraxial rays Peripheral rays Third Order Optics The paraxial approximation, sin q ~ q, is somewhat unsatisfactory if rays from the periphery of a lens are considered Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  8. What Kinds of Aberrations? • Monochromatic Aberration • Seidel Aberrations • Spherical Aberration • Coma • Astigmatism • Field Curvature • Distortion • Wave Aberrations (adaptive optics) • Defocus • Higher order • Chromatic Aberration (337, 357,391nm) • Longitudinal • Transverse Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  9. Size of image spot Incident angle (zenith angle) Spot Diagram of Ideal Fresnel Mirror 2D-simulation q = 0 deg q = 6 deg q : zenith angle q = 12 deg Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  10. Ray Tracing & Aberration of Fresnel Mirror full-simulation Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  11. Fresnel Mirror : 20 deg of Incident angle Spot diagram Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  12. Spot Diagram of Fresnel Mirror q : zenith angle q = 6 deg q = 0 deg q = 12 deg Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  13. Aberration Free Optics ? • No mirror such that rays from all directions (wide FOV) are well focused simultaneously • Not the case for astronomical telescope where FOV is always small • Solution would be real time focus to a given object or trigger Archimedes’ Mirror Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  14. EAS Photo Detector Micro Mirror Conrol VLSI How to remove Aberrations Mirror segmented & each mirror segment controlled independently -> Focusing of the sun at any incident angles -> Tracking of object(sun, EAS) at any angles allows an aberration free optics Archimedes’ Mirror Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  15. Tracking : aberration free imaging 1D-simulation mmirror Detector -0.5m 0 0.5m Air -200km 0 80 200km Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  16. 자료 M2N 제공 What is Silicon Micro Mirror ? • MEMS (MicroElectroMechanical Systems) • Recent technological advance in si industry • Originally developed for optical communication & display industry • Cost effectiveness due to standard silicon fab available • 100x100 mm2 in size or less • Each cell controlled independently • Types • DMD : Digital, electrostatic actuator, TI • TMA : Analog, PZT actuator, Daewoo • Others (thermal, membrane, …) Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  17. DMD mMirror : Electrostatic Actuation Texas Instrument Digital -> Two preset directions only Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  18. mirror y top electrode x piezoelectric layer bottom electrode supporting layer anchor • contraction to x-direction • expansion to y-direction q d V TMA mMirror : PZT(Piezoelectric) Actuation Daewoo Electronics Analog -> Variable direction Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  19. Linear Response of Tilting Angle Mirror Switching Speed T = 26.5 ms fr = 38kHz Performance of TMA mMirror • Max. tilting angle: 10 degree • Linear response • Switching speed: ~ 1 msec / 1o Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  20. MEMS Tracking Mirror (full Simulation) MEMS micromirror array Photo detector array Required angle for each cell Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  21. Zenith angle = 10 MEMS Tracking Mirror (full Simulation) Zenith angle = 0 Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  22. MEMS Mirror Photo detector array (40x40 cells) 1. Field resolution = 9.6x9.6 km2 • Trigger at Wide FOV • Zoom x4 • Zoom x16 • Tracking & event recording (or reset trigger, latency time=10 msec) • Trigger at Wide FOV • Zoom x4 • Zoom x16 • Tracking & event recording (or reset trigger, latency time=10 msec) • Trigger at Wide FOV • Zoom x4 • Zoom x16 • Tracking & event recording (or reset trigger, latency time=10 msec) • Trigger at Wide FOV • Zoom x4 • Zoom x16 • Tracking & event recording (or reset trigger, latency time=10 msec) Field of Air watch (160,000 km2 = 40x40 divisions) 2. Field resolution = 2.4x2.4 km2 3. Field resolution = 0.6x0.6 km2 4. Tracking Concept of Zoom & Tracking • “Zoom” -> “Adjustable Field Resolution” -> Wide FOV • “Tracking” -> Aberrations Free Image and Only Small No. of Detector Channels Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  23. Zoom-like Feature • Real time focusing -> aberration free optics, wide FOV • Image relocation -> zoom feature (like human eye), small no. of ch. (Ex) move an image captured on outer pixels of the detector toward the fine segmented center with 2-step trigger Relative error(%) in source zenith angleas increasing trigger stage Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  24. Requirements of mmirror for EECR Telescope • High Tilting Speed • 1 degree/msec possible at present technology, but factor 10 improvement is foreseen • Smaller size of pixel gives higher speed, but no. of ch. Increases • Large Tilting Angle • Close to 10 degrees, but factor 2 is foreseen • Also smaller size of pixel helps • Linearity (Tilting Angle .v. Applied Voltage) : Good linearity shown • Angle accuracy : 0.1o of resolution at present • Stability : Feed back approach as a solution • High Fill Factor : Depending on design. > 90% is preferred • Low power consumption : < 1 mW per 200mm cell, so ~25 W/m2 • Light Weight : 10 kg/m2 including electronics • Low Production Cost : $30/cm2, so $300,000/m2 Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  25. Advantage of MEMS Telescope (Summary) • Proposed Telescope for EECR study • Zoom-in feature -> large FOV • Tracking feature -> Aberration free system, large mirror size, only small no. of photo detector channels required -> significant reduction of cost, power, weight • Silicon allowsLight weight, thin, large mirror • Experience of ~1m2 silicon detector shows • 10 kg including electronics and support • 1.5 cm height • In situ calibration: improve focusing accuracy • Sun shield: protect photo detectors • Power generation: direct lights to solar cells • Other measurements: direct to 2nd photo detector Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  26. Parameters of MEMS Tracking Telescope Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  27. Plan • Tracking mirror R&D possibly funded in Nov. 2004 • 1st Prototype of micro mirror (6x6 cells) by mid 2005 • Test and prove the idea in 2005 • Tracking mirror telescope on satellite in 2007-2009 • Attached payload at ISS in future TUS-II TUS-I Tracking Mirror EECR (1020 eV) fluorescence Cerenkov Earth Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  28. Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  29. Aberration in Simple Fresnel Mirror simulation Mirror Photo Detector Array -0.5m 0 0.5m 400 km -200km 0 200km Field of Air -200km 0 200km Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  30. Trigger (Initial) Configuration of mmirrors • Multi-focus with 5 sections of mirrors • Max. variance in rotation angle = +-6O • FOV ~ 70O with >40% of photo efficiency Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  31. Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  32. Spot Diagram of Fresnel Mirror q : zenith angle q = 0 deg q = 6 deg q = 12 deg q = 20 deg Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  33. Spot Diagram of Fresnel Mirror q : zenith angle q = 0 deg q = 6 deg q = 12 deg q = 20 deg Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  34. TUS-II TUS-I Tracking Mirror EECR (1020 eV) fluorescence Cerenkov Earth TUS Russian Satellite in 2006 Fresnel Mirror + PMT • Stereo Eyes • Two fold detection • Aperture double • tau n measurement mirrors Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  35. Lens Curvature : f d Retina How to Focus : Proposed Telescope • Telescope for Astronomy, EUSO … : f and d both fixed • Camera : f fixed while d varied (zoom feature) • Human Eye : f varied while d fixed (zoom & tracking) • Our telescope : “like Human Eye” Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  36. t=1 Trigger & Zoom_1 mmirror array photo receiver (40 x 40 cells) 40 40 2.4 x 2.4 km2 9.6 x 9.6 km2 EAS on air 40 40 How Tracking Mirror Works? DEMO t=0 Wide FOV with poor resolution Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  37. t=3 Direction Finding & EAS tracking 0.6 x 0.6 km2 EAS direction continued t=2 Zoom_2 & Set fine resolution Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

  38. Il H. Park, A New Space Telescope, KPS, Jeju, 2004.12.21-23

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