Astronomical Spectroscopy with Electron-Multiplied CCDs (EMCCDs)

Key Workshop Objective

  • Understand the merits and limitations of EMCCDs in astronomical spectrographs and how to optimize their use

Date and Time July 28, 2015
Location: Hameetman Auditorium Cahill Center for Astronomy and Astrophysics, Caltech

Workshop Goals

  • 1) Understand the practical performance of current EMCCDs in astronomical applications.
  • 2) Identify scientific opportunities uniquely enabled by large format EMCCDs.
  • 3) Explore the design space of spectrograph (and mission) architectures suitable to exploit EMCCD advantages.
  • 4) Communicate shared interests and build a richer community of instrumentalists knowledgeable with EMCCD technology.


Organizing Committee: R. Dekany, E. Hamden, R. Jensen-Clem, G. Kyne, N. Konidaris, C. Shapiro (JPL)
Attendees: R. Dekany, E. Hamden, G. Kyne, P. Morrissey, G. Hallinan, R. Smith, S. Nikzad, C. Martin, J. Cohen, C. Steidel, K. Wallace, G. Hallinan, L. Harding (JPL), L. Hillenbrand, E. Kirby, N. Lingner, T. Goodsall (JPL), D. Mawet, J. Feliciano, J. Milburn, J. Fucik, E. Bellm, D. Neill, A. Jewell (JPL), T. Jones (JPL), M. Hoenk (JPL)
Could not attend: R. Demers (JPL), R. Riddle


* Pre-Session (8a) : Photon Counting CCD Tutorial: -- Roger Smith

* Special breakfast (9a)

* Morning Sessions (start at 9:30a) - N. Konidaris, Session Chair

  • Scientific advantages and disadvantages of EMCCDs for spectroscopy (1 hour) - Nick Konidaris
    • (Sensitivity / architecture flexibility / operations / integrating modes / dynamic range / data processing & management / calibration / etc.)
    • Technology roadmap / future devices / commercial intentions (TBC)
  • Commercial EMCCD camera comparison (10:30a) - Rich Dekany
  • Real-world experience with EMCCDs in astronomy (11p)
    • CHIMERA / WFIRST testing - Gregg Hallinan (confirmed) / Leon Harding (confirmed)

* Patio Lunch (provided, 12 noon)

* Afternoon Sessions (1pm) -- E. Hamden, Session Chair

  • Projects in development using EMCCDs (1-2p)
    • FIREBALL / GEONIS / NGDBSP / VERVE - Erika Hamden & Gillian Kyne / Nick Konidaris / Kent Wallace
  • Panel Discussion -- E. Hamden, Moderator (2-3p)
    • Lab demonstrations needed and/or planned tests
    • Technical issues: Dark Current / CIC / Low-T CTE / Lifecycle Issues
    • EMCCD calibration unique concerns

* Coffee Break (3p)

  • New applications / concept / science frontiers (3:20p)
  • General Discussion (4p) -- Rich Dekany, Moderator
    • Possible topics include:
      • Influencing vendors, commercial development / Coordinating EMCCD eval. and testing (incl. environ.) / Sky vs. Space backgrounds / Coincidence loss problems / Outlandish new ideas
      • Publishing more results from our real astronomy with EMCCDs

* Adjourn

* Happy Hour at Rath al Fresco


  • Add other external links here

Related Papers or References

  • Add paper links here


  • Messages to vendors
    • A lower noise output amplifier would help astronomers not have to run at as high a gain before entering the photon-counting regime.
      • Why are the current choices among commercial options so crumby?
    • Importance to this community to prove EM operation with deep-depletion (DD) CCDs?
  • First Light (France) is an alternative commercial EMCCD camera vendor; OCAM2K camera being used in SPHERE for wavefront sensing.
  • Other vendors for EMCCDs themselves?

  • Panel Discussion Notes
    • Panel: S. Nikzad, L. Harding, R. Jensen-Clem, N. Konidaris, T. Goodsall, E. Hamden (Moderator)
    • Q1: What kinds of tests of EMCCDs are your groups performing?
      • EH/FIREBALL: concentrating on dark current measurements right now
      • SN: improving QE, getting absolute QE values, particularly at short wavelengths + dark current, uniformity, and stability of performance; includes UV spectrometer studies
      • LH: testing for radiation damage, including impact on CIC, CTE, and dark current, also CTE more generally
      • C. Martin: this community would benefit from development of the optimal design independent of any one specific mission; how could we integrate efforts?
      • RJ-C: investigating photon arrival statistics for exoplanet search/study; issue: how are we sure that zero signal corresponds really to zero photons? Statistics/SNR in general
      • TG: starting to look into accurate measurement of quantum yield for UV applications (more than one e- per input photon).
      • ?: total radiation dose measurements
    • Q2: What have peer reviewers said in response to recent flight proposals?
      • SN: reviewers want to see test data from actual assets you plan to fly (exact format, etc.); more evidence of successful out-of-band rejection; sounding rocket demonstrations sometimes criticized for not following exact science objectives as flight mission. Are QE measurements real?
      • LH: Achieving high TRL numbers and the testing strategy to do that- not getting sidetracked or adding new complexity
      • R. Smith: would cubesat or ISS demonstrations help prove readiness; SN: yes, but care should be taken to demonstrate the right device, based on mission planning.
      • NK: as reviewer and reviewee, some researchers see to take EMCCD performance for granted; need to honestly represent understanding of advantages and limitations. Also stress things like high dynamic range given you can switch between modes.
      • RD: as we've heard today, for key applications the advantages are real and we should disseminate this better in the broader astronomy community.

Follow-on Action Items

  • Dekany: Add First Light to commercial vendor slide - 8/18/15 - DONE!
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf 150728_Commercial_EMCCDs.pdf r2 r1 manage 5953.5 K 2015-08-25 - 23:13 RichardDekany  
PDFpdf 150728_EMCCD_Workshop_TMAS.pdf r1 manage 31194.6 K 2015-08-25 - 23:14 RichardDekany  
PDFpdf EMCCDGuideCameras_small.pdf r1 manage 2413.0 K 2015-08-26 - 18:32 RichardDekany  
PowerPointpptx Photon_counting_CCD_tutorial.pptx r1 manage 16697.7 K 2015-08-25 - 23:19 RichardDekany  
PowerPointpptx VERVE.pptx r1 manage 7614.5 K 2015-07-28 - 20:07 RichardDekany  
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Topic revision: r21 - 2015-08-26 - RichardDekany
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