1.  Johann Kolb, Norbert Hubin  Mark Downing, Olaf Iwert, Dietrich Baade Simulation results:  Richard Clare Detectors for LGS WF sensing on the E-ELT 1AO for ELTs, Paris, 22-26 June 2009  AO needs for detectors  Derived specifications  Solutions

2. IR detectors development Large visible fast low-noise detector for Shack-Hartmann based AO WFS Existing visible high performance detector (i.e. CCD220) 3kHz low- noise detector AO Detectors needs on the E-ELT AO for ELTs, Paris, 22-26 June 2009 LGS GLAO NGS GLAO NGS SCAO LGS MCAO LTAO MOAO XAO IR Low order WFS Low order AO SH quad - cell PYR Other WFS… Vis TT sensors IR TT sensors 2 Guiding AO Detectors needs on the E-ELT

3. Adaptive Optics WFS detectors 3AO for ELTs, Paris, 22-26 June 2009 Existing system (MAD): 8x8 sub-apertures on an e2v CCD39 In development (VLT AO Facility): 40x40 sub-apertures on an e2v CCD220 Future (all EELT AO modules): 84x84 sub- apertures

4. Specifications / Spatial resolution I 4AO for ELTs, Paris, 22-26 June 2009 ¤ Number of pixels: 84x84 sub-apertures of 20x20 pixels = 1680 x 1680 pixels LLT Sodium layer Detector plane Pupil plane Side launch flux Need 14-20 pixels per sub-aperture To cover spot elongation in the most demanding AO systems Specifications Large visible fast low-noise detector for Shack-Hartmann based AO WFS ¤ Spatial resolution ¤ Temporal resolution ¤ Image quality

5. Specifications / Spatial resolution II 5AO for ELTs, Paris, 22-26 June 2009 ¤ Pixel size: 24 µm  Detector size ~ 40x40 mm Compromise between reasonable detector size (for yield) and easiness of alignment with small pixels ¤ PSF = charge diffusion = optical cross-talk: 0.8 pixels  “Blurs” the image  Simulations  PSF should be kept small

6. Specifications / Temporal resolution I 6AO for ELTs, Paris, 22-26 June 2009 ¤ Exposure time: variable between 1.4 and 5 / 10 (LGS / NGS) ms.  Corresponds to frame rates from 100 / 200 (NGS / LGS) to 700 Hz  All specifications should be met at any value in this range ¤ Latency 1: synchronicity within a sub-aperture  All pixels from a same sub-aperture should be exposed within 20 µs ¤ Latency 2: prompt and continuous transfer of pixel data to the detector output pins ¤ Read-out scheme : Either snapshot (frame-transfer CCD) or rolling-line (CMOS, NAOS IR sensor).  Rolling-line read-out = lines of pixels or of sub-apertures are read-out while the rest of the detector is integrating

7. Specifications / Temporal resolution II 7AO for ELTs, Paris, 22-26 June 2009 ¤ Image lag = “charges left behind”: < 2% per pixel at the next frame.  Is an issue for some technologies  Is equivalent to reduction of AO bandwidth ¤ Full-well capacity: > 4000 electrons ¤ Linearity: < 5% peak-to- peak

8. Specifications / Image quality I 8AO for ELTs, Paris, 22-26 June 2009 ¤ Average Read-Out Noise: < 3 e- rms/pixel/frame (goal <1e-)  Simulations  in this range, required laser power increases linearly with RON ¤ Average Dark current: < 0.5 e-/pixel/frame  Important at low frame rates

9. Specifications / Image quality II 9AO for ELTs, Paris, 22-26 June 2009 ¤ Read-Out Noise and dark current variation: 95%ile < twice the average value  Important in some technologies (CMOS) where all pixels don’t have the same RON and dark current ¤ Simulations  decreases performance with CoG, not much with Matched Filter

10. Specifications / Image quality III 10AO for ELTs, Paris, 22-26 June 2009 ¤ Quantum Efficiency:  LGS mode: > 85% at 589 nm  NGS mode: ¤ The same detector shall be used either for LGS or NGS WF sensing

11. Specifications / Image quality IV 11AO for ELTs, Paris, 22-26 June 2009 ¤ One cannot always have large full-well capacity and very-low read-out noise  CMOS allows regions of programmable gain. lowest RON, small full-well (worst elongation) low RON, average full-well high RON (but still small w.r.t. photon noise), large full-well System gain (e-/ADU) Full-well (e-) Noise target (e-) 0.22042.01 0.55122.06 110242.24 220482.83 440964.27 881928.25 161638416.12 ¤ Example: ¤ Simulations (R. Clare)  same performance as very low RON + large full-well, with Matched filter (degradation with CoG)

12. Other specifications 12AO for ELTs, Paris, 22-26 June 2009 ¤ Packaging ¤ Incidence angle ¤ Interfaces ¤ Cosmetics ¤ Pixel Response Non Uniformity ¤ Lifetime ¤ Stability w/ temperature and time

13. 13AO for ELTs, Paris, 22-26 June 2009 Large visible fast low-noise detector for Shack-Hartmann based AO WFS Solutions that meet the specifications

14. E-ELT AO WFS Detector Development Plan 14AO for ELTs, Paris, 22-26 June 2009 Design Study Technology Validation Development Testing/ Acceptance Production Phase Technology Demonstrator Scaled-down Demonstrator 200720082009201020112012201320142015 Authorize Production Testing 30 Science Devices Production Full size device meeting all specs. Engineering exercise Full Scale Demonstrator Retire Architecture/ Process Risks SDD Retire Pixel Risks TD 1 (2?) contract – 1xFP7, (1xother?)  24 months  Highly likely CMOS and down-select of TDs  Retire architectural risks by fab. ~ ¼ imager 3 contracts – 2xFP6 ELT-DS, 1xEELT Phase B:  11 months  All CMOS Imagers - most likely to succeed  retire pixel risk by demonstration noise x speed with good imaging capability 4 contracts - 2xFP6 ELT-DS, 2xEELT Phase A:  6 months  Investigated many different technologies  Most promising – CMOS Image, APD array and orthogonal EMCCD

15. CCD-based vs. CMOS-based concepts 15AO for ELTs, Paris, 22-26 June 2009 CCD: Charge Coupled Device Outside chip On chip Pixels  Charges transfer  Read-out (output register)  Controller, incl. digitization (ADCs) CMOS: Complimentary Metal Oxide Semiconductor  Charges creation  Pre-amp.  To the RTC  Charges transfer  Read-out (output register)  Controller, incl. digitization (ADCs)  Charges creation  Pre-amp.  To the RTC  Read-out (pixels transistors)  Voltages transfer  Digitization (ADCs)

16. 84x84 Sub-apertures Analog processing 100s ADCs Multiplexer/serializer Y-addressing Control Logic Y-addressing Control Logic Analog processing 100s ADCs Multiplexer/serializer Control Logic Control Logic each 20x20 pixels Vision of Full Size Device E-ELT AO WFS Detector design 16AO for ELTs, Paris, 22-26 June 2009 Example: frame transfer CCD: CCD220 Technology Demonstrator Scaled Down Demonstrator

17. Development status 17AO for ELTs, Paris, 22-26 June 2009 ¤ 3 Technology Demonstrator contracts awarded in 2008  2 in manufacturing, results end of the year  1 completed: frame rate of 1 kHz RON < 2 electrons Image lag Pixel Response Non Uniformity Linearity  Problems understood  Forward path proposed ¤ 1 Scaled Down Demonstrator contract  Call for Tender out this summer  Contract start beginning 2010  Funded by EC

18. How to motivate detectors suppliers? 18AO for ELTs, Paris, 22-26 June 2009 The Universe Atmosphere Telescope WFS in adaptor or instrument WFS detector EntityProviderRole Contain objects to observe Blur images Deliver the best possible image quality, with the maximum throughput ? ? EELT Provide pixels as representative as possible of the image: high spatial and temporal resolution, high QE Make the best use of received pixels to compute turbulence correction Wave Front reconstruction / Command to the Deformable Mirror EELT

19. 19AO for ELTs, Paris, 22-26 June 2009 AO Detectors needs on the E-ELT AO Detectors needs on the E-ELT

20. 20AO for ELTs, Paris, 22-26 June 2009 Specifications Large visible fast low-noise detector for Shack-Hartmann based AO WFS ¤ Spatial resolution ¤ Temporal resolution ¤ Image quality

21. Specifications / Spatial resolution I 21AO for ELTs, Paris, 22-26 June 2009 ¤ Number of pixels: 84x84 sub-apertures of 20x20 pixels = 1680 x 1680 pixels LLT Sodium layer Detector plane Pupil plane Side launch flux Need 14-20 pixels per sub-aperture To cover spot elongation in the most demanding AO systems

22. Specifications / Spatial resolution III 22AO for ELTs, Paris, 22-26 June 2009 ¤ Angle of incidence: the detector should accept:  F/10 to F/20  Variable angle of incidence within a sub-aperture  Maximum angle of incidence of 6.5º

23. Wavefront sensors on the E-ELT 23AO for ELTs, Paris, 22-26 June 2009 ¤ 42 meters aperture ¤ NGS (broad wavelength range) or LGS (spot elongation) ¤ Schack-Hartmann (requires many pixels) or other ¤ Telescope or post-focal AO: from 40 to 126 sub-apertures ¤ 100 – 700 Hz (EPICS 3 kHz) ¤ Excellent image quality

24. Example: telescope GLAO 24AO for ELTs, Paris, 22-26 June 2009  Pre-focal station, PRELIMINARY design  LGS WFS arms  NGS WFS arms  LGS WFS arms Volume for detector + controller  NGS WFS arms

25. CCD vs. CMOS 25AO for ELTs, Paris, 22-26 June 2009 CCD: Charge Coupled Device Digital data Voltages Charges  Pixels  Transfer  Read-out (output register)  Pre- amplification  Controller  To the RTC CMOS: Complimentary Metal Oxide Semiconductor  Pixels  Read-out (pixels transistors)  Transfer  Digitization (in ADCs)  Controller  To the RTC