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A Dedicated e2v-L3Vision CCD for Adaptive Optics Applications

A Dedicated e2v-L3Vision CCD for Adaptive Optics Applications.

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A Dedicated e2v-L3Vision CCD for Adaptive Optics Applications

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  1. A Dedicated e2v-L3Vision CCD for Adaptive Optics Applications Mark Downing, Norbert Hubin, Markus Kasper, Javier Reyes, Manfred Meyer, Dietrich BaadeEuropean Southern Observatory ESO (http://www.eso.org)Paul Jorden, Peter Pool, Sandy Denney, Wolfgang Suske, Kevin Hadfield, David Burt, Pat Wheelere2v technologies ltd (http://e2vtechnologies.com)Philippe Feautrier, Eric Stadler, David Mouillet. Domaine Universitaire LOAG (http://www-laog.obs.ujf-grenoble.fr/JRA2)Jean-Luc GACH, Philippe Balard, Christian Guillaume, Olivier Boissin. Laboratoire d'Astrophysique de Marseille LAM (http://www.lam.oamp.fr)José Javier Diaz. IAC, Institute of Astrophysics Canary Islands (http://www.iac.es)Thierry Fusco. ONERA (http://www.onera.fr)Detector WorkshopJune 2005 SDW2005 - Dedicated L3CCD for AO

  2. Residuals after differential PSF subtraction The Need VLT Planet Finder Coronographic image VLT/NACO • PF will detect faint planets close to very bright stars • with luminosity ratios > 105. • Achieved by performing ultra accurate differential measurements • requiring excellent image quality + stability from its AO system. • The WFS Detector is the critical component of this AO system • its performance is paramount not only to the success of PF but • most 2nd generation VLT instruments (e.g. MUSE, HAWK-I) • and future large telescopes such as OWL & TMT. SDW2005 - Dedicated L3CCD for AO

  3. Restricts technology choice Funding (Catalyst) ESO – for next generation of instruments OPTICON - European Infrastructure program JRA2:Fast detectors for AO applications: Philippe Feautrier Poster: Zero noise wavefront sensors development within the Opticon european network Deliver report and devices on a 2-3 year timescale, our profile is: • low risk. • Need guaranteed delivery of devices that meet requirements. Currently available technologies → split frame transfer CCD SDW2005 - Dedicated L3CCD for AO

  4. Present Systems Sub-apertures each 6x6 pixels Requirements Next Generation Systems 40x40 SH-WFS (mag~10, RON=1e-) 240x240 pixels 8x8 SH-WFS • 6x6 pixels/sub-aperture x 40x40 subapertures  240x240 pixels. • Versatility: 100% fill factor / 240x240 square grid array of pixels • Can be used with any type of WFS system; SH, curvature, or pyramid. • > 1 kHz frame rate to match the increased spatial sampling. • High QE, low RON and dark current (< 1e-/pixel/frame). SDW2005 - Dedicated L3CCD for AO

  5. 8 outputs e2v-CCD-50 e2v-CCD-39 e2v-CCD-220 MAD: Multi-Conjugate Adaptive Optics Demonstrator Poster: We must be MAD: Pushing FIERA to its limits - Roland Reiss Andrea Balestra, Claudio Cumani, Christoph Geimer, Javier Reyes, Enrico Marchetti Gain Registers Gain Registers Image Area 240x120 24□µm Image Area 240x120 24□µm Store Area Store Area 4 Outputs 4 Outputs 8 outputs Road Map of WFS Detectors Progressive increase in number of pixels , faster frame rate and lower RON. MAD-WFS CCD 80x80 pixels 4outputs 500Hz frame rate RON: 8-6 e/pixel QE: 70-80% NAOS-WFS CCD 128x128 pixels 2x8 outputs 25-600 Hz frame rate RON: 2.5-6.5 e/pixel QE: 80% Future-WFS CCD-220 240x240 pixels 8 L3 outputs 0.25-1.2 kHz frame rate RON: < 1(0.1)e/pixel QE: 90% SDW2005 - Dedicated L3CCD for AO

  6. Low RON vs High Red QE Compare CCDs with low RON < 1e to CCDs with better red QE but higher RON. Guided by simulations by Thierry Fusco for VLT PF Asked to investigate two detectors: CCD1 (L3Vision CCD) Good blue QE over 450-700nm RON = 0 & 1e-, but 2 multiplication gain noise. CCD2 (conventional but thick 450 µm fully depleted CCD) High QE over 450-1000nm. RON ~ 2, 3 & 5e- For QE alone, limit. mag. of CCD2 is better by: O.1 for yellow GS. O.5 for red GS. ∆m Dichroic CCD2 better due to higher red QE (same RON) QE Red GS Yellow GS CCD2 CCD1 λ Optimisation of Shack-Hartman-based wavefront sensor for XAO system T. Fusco, R. Conan, G. Rousset, M. Nicolle, C. Petit, D. Mouillet, A. Blanc, J.-F. Sauvage, J.-L. Beuzit. Proc. SPIE Int. Soc. Opt. Eng. 5490, 1155 (2004). SDW2005 - Dedicated L3CCD for AO

  7. White-Yellow GS Red GS Strehl ratio Strehl ratio MPE CCD L3CCD GS Magnitude. GS Magnitude. CCD1- L3CCD Wins • However, need to look at total picture – QE and RON. • Lower RON (~ 0.1e-) better than higher red QE even for red GS. • Reason e2v-L3Vision chosen. SDW2005 - Dedicated L3CCD for AO

  8. OP 4 Gain Registers Metal Buttressed 2Φ 10 Mhz Clocks for fast image to store transfer rates. 8 L3Vision Gain Registers/Outputs. Each 15Mpix./s. OP 3 OP 2 Gain Registers Store slanted to allow room for multiple outputs. OP 1 Image Area 240x120 24□µm Image Area 240x120 24□µm OP 8 OP 6 Gain Registers Gain Registers Store Area Store Area OP 7 OP 5 The Design Split frame transfer 8-output back-illuminated e2v L3Vision CCD. SDW2005 - Dedicated L3CCD for AO

  9. Good red QE important for red natural GS; especially for PF. Plan to have split wafer run in std Si and deep depletion. First time L3Vision produced in deep depletion Silicon. e2v Deep Depletion Std L3Vision Improve Red QE QE λ SDW2005 - Dedicated L3CCD for AO

  10. Rayleigh Back-scatter Add an Electronic Shutter Rayleigh LG Systems: • work by Rayleigh back-scatter of laser light from water molecules. • Advantage - enables use of pulsed lasers: • Commercially available. • Powerful. • Cheap - more photons per Euro. • Requires: • Exposure times of ~ 6.6 µs (2km x 3.3 µs/km) • Fast shutter open/close times of ~ µs • High extinction ratios (open/close sensitivity) > 104 to block large back-scatter ( Height -2) at low altitudes. • Solution → Electronic Shuttered CCD. • Additional design study to deliver 2 devices • Bonus no smearing → transfer image when shutter closed. Close Shutter 2 km Open Shutter 20 km altitude Pulsed Laser SDW2005 - Dedicated L3CCD for AO

  11. Some Design Trade-offs SDW2005 - Dedicated L3CCD for AO

  12. Charge Spread 0 . 5 æ ö 2kT/q Pixel Boundary ç ÷ @ 1-s z ç ÷ Depletion depth  VImageArea VIA V è ø IA V ImageArea Z VIA p-substrate n buried channel Depleted Undepleted Light Input 0V photon p+ PSF vs Dark Current/QE • Charge spread  thickness (z) and Image Area voltage, (VIA) • Even worse as depletion depth  VIA • Improve PSF by • Thinning device (z) • Get rid of undepleted region • Undesirable as lowers red QE • Increasing image area clock voltage • Run non-inverted, but 100 times the dark current. SDW2005 - Dedicated L3CCD for AO

  13. Proposed Camera Housing Detector boards Cooling plate L3Vision CCD Small Volume 56x120x235 38mm Width 20mm Height Example Only Length 80mm Package Tradeoffs Will use compact Peltier cooled package. • Able to fit in small space reserved for AO system. • Minimal support equipment – no LN2, no cryocoolers, no mechanical moving parts. There are conflicting requirements between: • Compactness solved by Peltier package. • Low temperature for low dark current. Reduce load on cooling by: • Reducing pin count (thermal conductivity): • Eliminate all but essential features – e.g. no SW. • Parallel up as many clocks and biases as possible; except Vod & Vrd kept separate to reduce cross-talk. • Reducing on-chip power dissipation: • Make clocks edges as slow as possible. • Bonus from metal buttressing. Increase available cooling by: • Designing custom Peltier. SDW2005 - Dedicated L3CCD for AO

  14. Controller and Test Plan • Observatoire de Marseille are building the test controller: • Loan to e2v for testing. • Very challenging – go along and talk to Jean-Luc Gach. • ESO developing NGC (New General Controller) for deployment on VLT. • Test Plan: • E2v • Measure normal parameters → noise, gain, cosmetics, dark current, smearing, and CTE. • IAC (Canary Islands) and ESO • Do full acceptance tests. • Plus measure more exotic parameters → crosstalk, PRNU, fringing, and PSF. Poster: NGC Front-end for CCDs and AO applications. Javier Reyes, Mark Downing, Manfred Meyer, Leander Mehrgan, Ralf Conzelmann. Poster: Software for the New General detector Controller. Claudio Cumani, Andrea Balestra, Joerg Stegmeier. Oral: NGC Detector Array Controller Based on High Speed Serial. Manfred Meyer, Dietrich Baade, Gert Finger, Leander Mehrgan, Javier Reyes, Joerg Stegmaier. Poster: A dedicated controller for Adaptive Optics L3CCD developments. Jean-Luc Gach, Philippe Balard, Olivier Boissin, C. Guillaume. SDW2005 - Dedicated L3CCD for AO

  15. Challenges • The challenges are the number of technology “cutting edge” features: • L3Vision for AO WFS –very promising but not yet fully evaluated. • Optimized Peltier cooled package for compactness. • The technology firsts with L3Vision: • L3Vision with multiple outputs to reduce clocking rate of individual output nodes. • Metal buttressing to reduce frame transfer smear. • Deep depletion for better red response. • Electronic shutter to enable Rayleigh LG systems. • The baseline development is low risk. • e2v, OPTICON, and ESO have formed a very good partnership. • Confident to meet schedule: • Contract signed last April after many months of constructive negotiations. • Critical Design Review – Aug 2005. • Science devices will be available – Q1 2007. SDW2005 - Dedicated L3CCD for AO

  16. ENDMany Thanks for Listening SDW2005 - Dedicated L3CCD for AO

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