Mr. Gerd H. Jakob Profile

Gerd H. Jakob

Head of Instruments and Cryogenic Systems Group at European Southern Observatory

SPIE Involvement:

Author

Publications (41)

Proceedings Article | 30 August 2022 Presentation + Paper

Lessons learned from the NEAR experiment and prospects for the upcoming mid-IR HCI instruments

Prashant Pathak, Markus Kasper, Olivier Absil, Gilles Orban de Xivry, Ulli Käufl, Gerd Jakob, Ralf Siebenmorgen, Serban Leveratto, Eric Pantin

Proceedings Volume 12185, 121851T (2022) https://doi.org/10.1117/12.2630040

KEYWORDS: Human-computer interaction, Mid-IR, Coronagraphy, Point spread functions, Planets, Exoplanets, Image processing, Sensors, Adaptive optics, Digital filtering

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Proceedings Article | 25 August 2022 Presentation + Paper

ESO ELT: vibration performance and budget verification: measured equipment data as input to telescope model

B. Sedghi, P. Zuluaga Ramirez, D. Pilbauer, S. Leveratto, U. Lampater, M. Müller, G. Jakob, M. Haug, M. Accardo, Y. Lammen, J. Abad-Pastor, J. C. González-Herrera

Proceedings Volume 12187, 1218714 (2022) https://doi.org/10.1117/12.2628907

KEYWORDS: Telescopes, Mirrors, Wavefronts, Actuators, Control systems, Adaptive optics, Vibrational characterization, Modeling and simulation, Vibration isolation, Active vibration damping

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SPIE Journal Paper | 6 June 2022

Management of equipment vibration for extremely large telescopes

David Adams, Bartholomew Fordham, Gerd Jakob, Douglas MacMartin, Babak Sedghi, David Schwartz, Hugh Thompson, Tony Travouillon, Byron Smith, Peter Kerrian

JATIS, Vol. 8, Issue 02, 021512, (June 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.2.021512

KEYWORDS: Telescopes, Fluctuations and noise, Adaptive optics, Large telescopes, Mirrors, Observatories, Wavefronts, Optical isolators, Cryocoolers, Actuators

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Proceedings Article | 18 December 2020 Presentation + Paper

A status report on the instruments for ESO’s Extremely Large Telescope

Suzanne Ramsay, Paola Amico, Naidu Bezawada, Fabio Biancat Marchet, Patrick Caillier, Michele Cirasuolo, Ralf Conzelmann, Reinhold Dorn, Sebastian Egner, Christoph Frank, Elizabeth George, Frederic Gonte, Juan Carlos González Herrera, Peter Hammersley, Christoph Haupt, Derek Ives, Gerd Jakob, Florian Kerber, Bertrand Koehler, Sylvain Oberti, Christian Schmid, Johannes Schimpelsberger, Ulf Seemann, Ralf Siebenmorgen, Roberto Tamai, Joël Vernet

Proceedings Volume 11447, 114471U (2020) https://doi.org/10.1117/12.2562555

KEYWORDS: Large telescopes, Spectrographs, Adaptive optics, Imaging systems, Cameras, Mid-IR, Tomography, Astronomical imaging

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Proceedings Article | 13 December 2020 Presentation + Paper

ESO ELT - vibration sources characterization: a step forward towards requirement and performance verification

B. Sedghi, P. Zuluaga-Ramírez, U. Lampater, D. Pilbauer, S. Leveratto, G. Jakob, M. Müller, J. Abad-Pastor, J. C. González-Herrera, S. Patti

Proceedings Volume 11450, 114500N (2020) https://doi.org/10.1117/12.2561548

KEYWORDS: Telescopes, Cooling systems, Wavefronts, Systems modeling, Observatories, Performance modeling

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Proceedings Article | 3 January 2020 Paper

The ESO Extremely Large Telescope instrumentation programme

Suzanne Ramsay, Paola Amico, Naidu Bezawada, Michele Cirasuolo, Frédéric Derie, Sebastian Egner, Elizabeth George, Frédéric Gonté, Juan Carlos González Herrera, Peter Hammersley, Christoph Haupt, Jeroen Heijmans, Derek Ives, Gerd Jakob, Florian Kerber, Bertrand Koehler, Vincenzo Mainieri, Antonio Manescau, Sylvain Oberti, Paolo Padovani, Celine Peroux, Ralf Siebenmorgen, Roberto Tamai, Joël Vernet

Proceedings Volume 11203, 1120303 (2020) https://doi.org/10.1117/12.2541400

KEYWORDS: Adaptive optics, Spectrographs, Telescopes, Large telescopes, Cameras, Spectroscopy, Exoplanets, Stars, Spectral resolution, Laser guide stars

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Proceedings Article | 10 July 2018 Presentation + Paper

Cryogenic cooling systems for the ELT instruments

Gerd Jakob, Matteo Accardo, Marcus Haug, Volker Heinz

Proceedings Volume 10706, 107061D (2018) https://doi.org/10.1117/12.2313316

KEYWORDS: Cryogenics, Telescopes, Observatories, Cooling systems, Commercial off the shelf technology, Nitrogen, Cryocoolers, Vacuum equipment, Astronomical instrumentation, Vibration isolation

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Proceedings Article | 9 July 2018 Paper

MATISSE: performance in laboratory, results of AIV in Paranal, and first results on sky

S. Robbe-Dubois, S. Lagarde, P. Antonelli, B. Lopez, F. Allouche, C. Bailet, Ph. Berio, Y. Bresson, J.-M. Clausse, P. Cruzalèbes, Y. Fantei-Caujolle, A. Marcotto, A. Matter, A. Meilland, F. Millour, S. Morel, R. Petrov, S. Rousseau, A. Soulain, G. Zins, M. Lehmitz, W. Laun, T. Adler, R. Klein, T. Maurer, F. Bettonvil, E. Eldswick, U. Beckmann, M. Heininger, P. Bristow, A. Glindemann, N. Hubin, L. Jochum, Th. Rivinus, M. Schoeller, J. Beltran, P. Bourget, A. Gallenne, Th. Guerlet, X. Haubois, D. Ives, G. Jakob, A. Meister, M. Riquelme, N. Schuhler, C. Stephan, P. Toledo, K. Tristam, J. Woillez, U. Neumann, A. Chelli, F. Guitton, K. Meisenheimer, B. Pichon, A. Spang, J. Varga, Th. Henning, W. Jaffe, L. Pasquini, Ph. Stee, G. Weigelt

Proceedings Volume 10701, 107010H (2018) https://doi.org/10.1117/12.2313270

KEYWORDS: L band, Photovoltaics, Spectral resolution, Visibility, Sensors, Interferometry, Astatine, Spatial filters, Telescopes, Calibration

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MATISSE (Multi AperTure mid-Infrared SpectroScopic Experiment) is the spectro-interferometer for the VLTI of the European Southern Observatory (ESO), operating in the L-, M- and N- spectral bands, and combining up to four beams from the unit or the auxiliary telescopes (UTs or ATs). MATISSE will offer new breakthroughs in the study of circumstellar environments by allowing the mapping of the material distribution, the gas and essentially the dust. The instrument consists in a warm optical system (WOP) accepting four beams from the VLTI and relaying them after a spectral splitting to cold optical benches (COB) located in two separate cryostats, one in L-M- band, and one in N-band. The test plan of the complete instrument has been conducted at the Observatoire de la Côte d’Azur in order to confirm the compliance of the performance with the high-level requirements. MATISSE has successfully passed the Preliminary Acceptance in Europe the 12th September 2017. Following this result, ESO gave approval for the instrument to be shipped to Paranal. The Alignment, Integration and Verification phase was conducted until end of February 2018, at the end of which first observations on sky have been performed to test the operations with the VLTI and to obtain first stellar light. The two first runs of the commissioning followed, respectively in March and in May 2018. It has the goal to optimize the MATISSE-VLTI communication, the acquisition procedures and the interface parameters. The observations were performed on bright L-M- and N- stars, with four ATs located on short baselines and UTs. The limit magnitudes will be deduced.

This paper reports on the performance of the instrument measured in laboratory (results of test plan in Nice and AIV in Paranal) in terms of spectral coverage, dispersion laws and spectral resolutions, and transfer function analysis: instrumental contrast, visibility accuracy, accuracy of the differential phase, of the closure-phase and of the differential visibility. It also provides results of the first tests on sky and the planning of the on-going commissioning.

Proceedings Article | 6 July 2018 Presentation + Paper

Instrumentation for ESO's Extremely Large Telescope

Suzanne Ramsay, Mark Casali, Paola Amico, Naidu Bezawada, Michele Cirasuolo, Ralf Conzelmann, Sebastian Egner, Christoph Frank, Elizabeth George, Juan Carlos González Herrera, Peter Hammersley, Christoph Haupt, Jeroen Heijmans, Derek Ives, Gerd Jakob, Florian Kerber, Betrand Koehler, Vincenzo Mainieri, Antonio Manescau, Enrico Marchetti, Sylvain Oberti, Paolo Padovani, Christian Schmid, Johannes Schimpelsberger, Ralf Siebenmorgen, Roberto Tamai, Joël Vernet

Proceedings Volume 10702, 107021P (2018) https://doi.org/10.1117/12.2313540

KEYWORDS: Sensors, Adaptive optics, Telescopes, Cameras, Spectrographs, Imaging spectroscopy, Wavefront sensors, Cryogenics, Large telescopes, Spectroscopes

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Proceedings Article | 6 July 2018 Presentation + Paper

NEAR: new earths in the Alpha Cen Region (bringing VISIR as a "visiting instrument" to ESO-VLT-UT4)

Hans-Ulrich Käufl, Markus Kasper, Robin Arsenault, Gerd Jakob, Serban Leveratto, Gerard Zins, Eloy Fuenteseca, Miguel Riquelme, Ralf Siebenmorgen, Michael Sterzik, Nancy Ageorges, Sven Gutruf, Dirk Kampf, Arnd Reutlinger, Olivier Absil, Brunella Carlomagno, Olivier Guyon, Pete Klupar, Dimitri Mawet, Garreth Ruane, Mikael Karlsson, Eric Pantin, Kjetil Dohlen

Proceedings Volume 10702, 107020D (2018) https://doi.org/10.1117/12.2313395

KEYWORDS: Coronagraphy, Telescopes, Stars, Adaptive optics, Sensors, Mirrors, Planets, Optical filters

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Proceedings Article | 4 August 2016 Paper

An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status

A. Matter, B. Lopez, P. Antonelli, M. Lehmitz, F. Bettonvil, U. Beckmann, S. Lagarde, W. Jaffe, R. Petrov, P. Berio, F. Millour, S. Robbe-Dubois, A. Glindemann, P. Bristow, M. Schoeller, T. Lanz, T. Henning, G. Weigelt, M. Heininger, S. Morel, P. Cruzalebes, K. Meisenheimer, R. Hofferbert, S. Wolf, Y. Bresson, T. Agocs, F. Allouche, J.-C. Augereau, G. Avila, C. Bailet, J. Behrend, G. van Belle, J.-P. Berger, R. van Boekel, P. Bourget, R. Brast, J.-M. Clausse, C. Connot, R. Conzelmann, G. Csepany, W. Danchi, M. Delbo, C. Dominik, A. van Duin, E. Elswijk, Y. Fantei, G. Finger, A. Gabasch, F. Gonté, U. Graser, F. Guitton, S. Guniat, M. De Haan, P. Haguenauer, H. Hanenburg, K.-H. Hofmann, M. Hogerheijde, R. ter Horst, J. Hron, C Hummel, J. Isderda, D. Ives, G. Jakob, A. Jasko, P. Jolley, S. Kiraly, J. Kragt, T. Kroener, G. Kroes, S. Kuindersma, L. Labadie, W. Laun, C. Leinert, J.-L. Lizon, C. Lucuix, A. Marcotto, F. Martinache, G. Martinot-Lagarde, N. Mauclert, L. Mehrgan, A. Meilland, M. Mellein, S. Menardi, A. Merand, U. Neumann, E. Nussbaum, S. Ottogalli, R. Palsa, J. Panduro, E. Pantin, I. Percheron, T. Phan Duc, J.-U. Pott, E. Pozna, R. Roelfsema, G. Rupprecht, D. Schertl, C. Schmidt, M. Schuil, A. Spang, J. Stegmeier, N. Tromp, F. Vakili, M. Vannier, K. Wagner, L. Venema, J. Woillez

Proceedings Volume 9907, 99070A (2016) https://doi.org/10.1117/12.2233052

KEYWORDS: Mid-IR, Interferometry, Telescopes, Signal detection, Sensors, Stars, Spectral resolution, Fourier transforms, L band, Cameras

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Proceedings Article | 3 August 2016 Paper

VISIR upgrade overview: all's well that ends well

Florian Kerber, Hans Ulrich Käufl, Konrad Tristram, Daniel Asmus, Pedro Baksai, Nicola Di Lieto, Danuta Dobrzycka, Philippe Duhoux, Gert Finger, Christian Hummel, Derek Ives, Gerd Jakob, Lars Lundin, Dimitri Mawet, Leander Mehrgan, Eric Pantin, Miguel Riquelme, Joel Sanchez, Stefan Sandrock, Ralf Siebenmorgen, Jörg Stegmeier, Alain Smette, Julian Taylor, Mario van den Ancker, Guillermo Valdes, Lars Venema

Proceedings Volume 9908, 99080D (2016) https://doi.org/10.1117/12.2232441

KEYWORDS: Sensors, Mid-IR, Imaging spectroscopy, Detector arrays, Imaging systems, Image quality, Telescopes, Coronagraphy, Stars, Spectroscopy

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We present an overview of the VISIR instrument after its upgrade and return to science operations. VISIR is the midinfrared imager and spectrograph at ESO’s VLT. The project team is comprised of ESO staff and members of the original VISIR consortium: CEA Saclay and ASTRON. The project plan was based on input from the ESO user community with the goal of enhancing the scientific performance and efficiency of VISIR by a combination of measures: installation of improved hardware, optimization of instrument operations and software support. The cornerstone of the upgrade is the 1k by 1k Si:As AQUARIUS detector array manufactured by Raytheon. In addition, a new prism spectroscopic mode covers the whole N-band in a single observation. Finally, new scientific capabilities for high resolution and high-contrast imaging are offered by sub-aperture mask and coronagraphic modes. In order to make optimal use of favourable atmospheric conditions, a water vapour monitor has been deployed on Paranal, allowing for real-time decisions and the introduction of a user-defined constraint on water vapour. During the commissioning in 2012, it was found that the on-sky sensitivity of the AQUARIUS detector was significantly below expectations. Extensive testing of the detector arrays in the laboratory and on-sky enabled us to diagnose the cause for the shortcoming of the detector as excess low frequency noise. It is inherent to the design chosen for this detector and cannot be remedied by changing the detector set-up. Since this is a form of correlated noise, its impact can be limited by modulating the scene recorded by the detector. After careful analysis, we have implemented fast (up to 4 Hz) chopping with field stabilization using the secondary mirror of the VLT. During commissioning, the upgraded VISIR has been confirmed to be more sensitive than the old instrument, and in particular for low-resolution spectroscopy in the N-band, a gain of a factor 6 is realized in observing efficiency. After overcoming several additional technical problems, VISIR is back in Science Operations since April 2015. In addition an upgrade of the IT infrastructure related to VISIR has been conducted in order to support burst-mode operations. Science Verification of the new modes was performed in Feb 2016. The upgraded VISIR is a powerful instrument providing close to background limited performance for diffraction-limited observations at an 8-m telescope. It offers synergies with facilities such as ALMA, JWST, VLTI and SOFIA, while a wealth of targets is available from survey works like WISE. In addition, it will bring confirmation of the technical readiness and scientific value of several aspects for future mid-IR instrumentation at Extremely Large Telescopes. We also present several lessons learned during the project.

Proceedings Article | 27 July 2016 Paper

CIAO: wavefront sensors for GRAVITY

Silvia Scheithauer, Wolfgang Brandner, Casey Deen, Tobias Adler, Henri Bonnet, Pierre Bourget, Fanny Chemla, Yann Clenet, Francoise Delplancke, Monica Ebert, Frank Eisenhauer, Michael Esselborn, Gert Finger, Eric Gendron, Adrian Glauser, Frederic Gonte, Thomas Henning, Stefan Hippler, Armin Huber, Zoltan Hubert, Gerd Jakob, Lieselotte Jochum, Laurent Jocou, Sarah Kendrew, Ralf Klein, Johann Kolb, Martin Kulas, Werner Laun, Rainer Lenzen, Marcus Mellein, Eric Müller, Javier Moreno-Ventas, Udo Neumann, Sylvain Oberti, Jürgen Ott, Laurent Pallanca, Johana Panduro, Jose Ramos, Miguel Riquelme, Ralf-Rainer Rohloff, Gérard Rousset, Nicolas Schuhler, Marcos Suarez, Gerard Zins

Proceedings Volume 9909, 99092L (2016) https://doi.org/10.1117/12.2232997

KEYWORDS: Wavefront sensors, Telescopes, Adaptive optics, Observatories, Infrared telescopes, Stars, Infrared sensors, Wavefront sensors, Infrared telescopes, Infrared radiation, Sensors, Mirrors

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Proceedings Article | 26 July 2016 Paper

Deformable mirrors development program at ESO

Stefan Stroebele, Elise Vernet, Martin Brinkmann, Gerd Jakob, Paul Lilley, Mark Casali, Pierre-Yves Madec, Markus Kasper

Proceedings Volume 9909, 99090O (2016) https://doi.org/10.1117/12.2232536

KEYWORDS: Deformable mirrors, Adaptive optics, Actuators, Telescopes, Adaptive optics, Mirrors, Prototyping, Planets, Stars, Ferroelectric materials, Turbulence

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Proceedings Article | 5 July 2016 Paper

E-ELT vibration modeling, simulation, and budgeting

B. Sedghi, M. Müller, G. Jakob

Proceedings Volume 10012, 1001202 (2016) https://doi.org/10.1117/12.2200926

KEYWORDS: Wavefronts, Performance modeling, Device simulation, Telescopes, Control systems, Vibration simulation, Integrated modeling, Vibration control, Error analysis, Mirrors, Interfaces, Adaptive optics, Motion models, Finite element methods, Observatories

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Proceedings Article | 31 July 2014 Paper

VISIR upgrade overview and status

Florian Kerber, Hans-Ulrich Käufl, Pedro Baksai, Nicola Di Lieto, Danuta Dobrzycka, Philippe Duhoux, Gert Finger, Stephanie Heikamp, Derek Ives, Gerd Jakob, Lars Lundin, Dimitri Mawet, Leander Mehrgan, Yazan Momany, Vincent Moreau, Eric Pantin, Miguel Riquelme, Stefan Sandrock, Ralf Siebenmorgen, Alain Smette, Julian Taylor, Mario van den Ancker, Guillermo Valdes, Lars Venema, Ueli Weilenmann

Proceedings Volume 9147, 91470C (2014) https://doi.org/10.1117/12.2055172

KEYWORDS: Sensors, Spectroscopy, Mid-IR, Imaging systems, Imaging spectroscopy, Prisms, Coronagraphy, Quantum efficiency, Detector arrays, Stars

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We present an overview of the VISIR upgrade project. VISIR is the mid-infrared imager and spectrograph at ESO’s VLT. The project team is comprised of ESO staff and members of the original VISIR consortium: CEA Saclay and ASTRON. The project plan is based on input from the ESO user community with the goal of enhancing the scientific performance and efficiency of VISIR by a combination of measures: installation of improved hardware, optimization of instrument operations and software support. The cornerstone of the upgrade is the 1k by 1k Si:As AQUARIUS detector array (Raytheon) which has been carefully characterized in ESO’s IR detector test facility (modified TIMMI 2 instrument). A prism spectroscopic mode will cover the N-band in a single observation. New scientific capabilities for high resolution and high-contrast imaging will be offered by sub-aperture mask (SAM) and phase-mask coronagraphic (4QPM/AGPM) modes. In order to make optimal use of favourable atmospheric conditions a water vapour monitor has been deployed on Paranal, allowing for real-time decisions and the introduction of a user-defined constraint on water vapour. During the commissioning in 2012 it was found that the on-sky sensitivity of the AQUARIUS detector was significantly below expectations and that VISIR was not ready to go back to science operations. Extensive testing of the detector arrays in the laboratory and on-sky enabled us to diagnose the cause for the shortcoming of the detector as excess low frequency noise (ELFN). It is inherent to the design chosen for this detector and can’t be remedied by changing the detector set-up. Since this is a form of correlated noise its impact can be limited by modulating the scene recorded by the detector. We have studied several mitigation options and found that faster chopping using the secondary mirror (M2) of the VLT offers the most promising way forward. Faster M2 chopping has been tested and is scheduled for implementation before the end of 2014 after which we plan to re-commission VISIR. In addition an upgrade of the IT infrastructure related to VISIR is planned in order to support burst-mode operations. The upgraded VISIR will be a powerful instrument providing close to background limited performance for diffraction-limited observations at an 8-m telescope. It will offer synergy with facilities such as ALMA, JWST, VLTI and SOFIA, while a wealth of targets is available from survey work (e.g. VISTA, WISE). In addition it will bring confirmation of the technical readiness and scientific value of several aspects of potential mid-IR instrumentation at Extremely Large Telescopes.

Proceedings Article | 28 July 2014 Paper

Vibration specifications for VLT instruments

Gerd Jakob, Jean-Louis Lizon

Proceedings Volume 9147, 91474W (2014) https://doi.org/10.1117/12.2054475

KEYWORDS: Magnesium, Head, Vibrometry, Telescopes, Mirrors, Nomenclature, Spatial resolution, Cryogenics, Standards development, Calibration

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ESO invested enormous effort in developing and commissioning the VLT-Interferometer (VLT-I), a unique facility providing a spatial resolution equivalent to that of a 200m-telescope. Complementary to the regular VLT operations, latterly additional 230 nights per year were scheduled to execute scientific observations with large VLT-I baselines. But to the same degree as the VLT-I performance and stability were improving over the past years, likewise the vibration sensitivity of the optical system was increasing and stricter requirements on mechanical stability were necessary. As a consequence ESO started years ago an extensive program to identify and mitigate potential vibration issues. In the scope of this work, the mechanical vibrations induced by cryo-coolers, widely used in ESO’s VLT instrumentation suite, were diagnosed as one of the major disturbance sources. In order to be able to better control their impact, the development of a more significant vibration specification for VLT instruments became essential. In the course of preparing such a specification, we first followed an experimental approach where we installed a dedicated dummy instrument equipped with current ESO standard cryo-coolers in different VLT foci configurations and performed a comprehensive vibration measurement test campaign under real VLT/VLT-I operation conditions. All obtained vibration measurement data were spectral analyzed with respect to the actual VLT-I optical path length difference acceptance levels. This campaign gave valuable information about typical cryo-cooler induced vibration levels and their consequence for VLT-I operations. It also enabled the release if novel conform cryo-cooler instrument design and operation recommendations. This paper describes the applied vibration measurement methodology on the basis of examples, the development and description of the significant VLT instrument vibration specification, and a proposal for a generic verification procedure for standalone instruments or sub-units prior final acceptance.

Proceedings Article | 24 July 2014 Paper

MATISSE status report and science forecast

B. Lopez, S. Lagarde, W. Jaffe, R. Petrov, M. Schöller, P. Antonelli, U. Beckman, Ph. Bério, F. Bettonvil, U. Graser, F. Millour, S. Robbe-Dubois, L. Venema, S. Wolf, P. Bristow, A. Glindemann, J.-C. Gonzalez, Th. Lanz, T. Henning, G. Weigelt, T. Agócs, J.-C. Augereau, G. Ávila, C. Bailet, J. Behrend, J.-P. Berger, Roy von Boekel, S. Bonhomme, P. Bourget, R. Brast, Y. Bresson, J. Clausse, O. Chesneau, G. Csépány, C. Connot, A. Crida, W. Danchi, M. Delbo , F. Delplancke, C. Dominik, M. Dugué, E. Elswijk, Y. Fanteï, G. Finger, A. Gabasch, P. Girard, V. Girault, P. Gitton, A. Glazenborg, F. Gonté, F. Guitton, S. Guniat, M. De Haan, P. Haguenauer, H. Hanenburg, M. Heininger, K.-H. Hofmann, M. Hogerheijde, R. ter Horst, J. Hron, Y. Hughes, D. Ives, G. Jakob, A. Jaskó, P. Jolley, J. Kragt, R. Köhler, T. Kroener, G. Kroes, L. Labadie, W. Laun, M. Lehmitz, Ch. Leinert, J. Lizon, Ch. Lucuix, A. Marcotto, F. Martinache, A. Matter, G. Martinot-Lagarde, N. Mauclert, L. Mehrgan, A. Meilland, M. Mellein, S. Ménardi, J. Menut, K. Meisenheimer, S. Morel, L. Mosoni, R. Navarro, U. Neumann, E. Nussbaum, S. Ottogalli, R. Palsa, J. Panduro, E. Pantin, I. Percheron, T. Phan Duc, J.-U. Pott, Eszter Pozna, F. Przygodda, A. Richichi, F. Rigal, G. Rupprecht, D. Schertl, J. Stegmeier, L. Thiam, N. Tromp, M. Vannier, F. Vakili, G. van Belle, K. Wagner, J. Woillez

Proceedings Volume 9146, 91460M (2014) https://doi.org/10.1117/12.2056419

KEYWORDS: Interferometry, Sensors, Mid-IR, Stars, Telescopes, Visibility, Planets, Spectral resolution, Photometry, Fourier transforms

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Proceedings Article | 23 July 2014 Paper

AQUARIUS: the next generation mid-IR detector for ground-based astronomy, an update.

Derek Ives, Gert Finger, Gerd Jakob, Udo Beckmann

Proceedings Volume 9154, 91541J (2014) https://doi.org/10.1117/12.2055837

KEYWORDS: Sensors, Telescopes, Mid-IR, Astronomy, Quantum efficiency, Mirrors, Manufacturing, Multiplexers, Doping, Data analysis

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ESO has already published data from a preliminary laboratory analysis on the new mid-IR detector, AQUARIUS, at the previous SPIE conference of 2012, held in Amsterdam². This data analysis indicated that this new mid-IR Si:As IBC detector, from Raytheon Vision Systems, was an excellent astronomical detector when compared to previous generations of this detector type, specifically in terms of stability, read noise and cosmetic quality. Since that time, the detector has been deployed into the VISIR¹ instrument at the VLT, with very mixed performance results, especially when used with the telescope secondary mirror, to chop between two areas of sky to do background subtraction and at the same time when many frames are co-added to improve the signal to noise performance. This is the typical mode of operation for a mid-IR instrument on a ground based telescope. Preliminary astronomical data analysis indicated that the new detector was a factor of two to three times less sensitive in terms of its signal to noise per unit time performance when directly compared to the old DRS detector that AQUARIUS was designed to replace. To determine the reason for this loss of sensitivity, the instrument was removed from the telescope and not offered to the ESO user community. A detector testing campaign was then initiated in our laboratory to determine the reasons for this loss of sensitivity, assuming that it was an issue with the new detector itself. This paper reports on our latest laboratory measurements to determine the reasons for this loss of sensitivity. We specifically report on indirect measurements made to measure the quantum efficiency of the detector, which can be difficult to measure directly. We also report on a little known source of noise, called Excess Low Frequency Noise (ELFN). Detailed analysis and testing has confirmed that this ELFN is the reason for the loss of instrument sensitivity. This has been proven by a re-commissioning phase at the telescope with the instrument and the detector. A new set of observing parameters and observational regime have been developed to help to mitigate the ELFN. We outline a possible explanation for the source of the EFLN, learnt from a literature search and discussion with the manufacturer.

Proceedings Article | 27 September 2012 Paper

VISIR upgrade overview and status

Florian Kerber, Hans Ulrich Käufl, Pedro Baksai, Danuta Dobrzycka, Gert Finger, Derek Ives, Gerd Jakob, Eric Lagadec, Lars Lundin, Dimitri Mawet, Leander Mehrgan, Margaret Moerchen, Yazan Momany, Vincent Moreau, Eric Pantin, Miguel Riquelme, Ralf Siebenmorgen, Armin Silber, Alain Smette, Julian Taylor, Mario van den Ancker, Lars Venema, Ueli Weilenmann, Irina Yegorova

Proceedings Volume 8446, 84460E (2012) https://doi.org/10.1117/12.924979

KEYWORDS: Spectroscopy, Sensors, Imaging spectroscopy, Mid-IR, Calibration, Prisms, Coronagraphy, Observatories, Imaging systems, Stars

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Proceedings Article | 25 September 2012 Paper

AQUARIUS: the next generation mid-IR detector for ground-based astronomy

Derek Ives, Gert Finger, Gerd Jakob, Siegfried Eschbaumer, Leander Mehrgan, Manfred Meyer, Joerg Steigmeier

Proceedings Volume 8453, 845312 (2012) https://doi.org/10.1117/12.925844

KEYWORDS: Sensors, Mid-IR, Signal detection, Astronomy, Photons, Field effect transistors, Interference (communication), Detector development, Multiplexers, Nondestructive evaluation

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Proceedings Article | 24 September 2012 Paper

An experimental VLT cryo-cooler instrumentation vibration analysis

Gerd Jakob, Jean-Louis Lizon

Proceedings Volume 8446, 844638 (2012) https://doi.org/10.1117/12.925373

KEYWORDS: Head, Telescopes, Mirrors, Vibrometry, Cryogenics, Sensors, Current controlled current source, Copper, Space telescopes, Optical instrument design

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Proceedings Article | 12 September 2012 Paper

Perspective of imaging in the mid-infrared at the Very Large Telescope Interferometer

B. Lopez, S. Lagarde, P. Antonelli, W. Jaffe, R. Petrov, L. Venema, Sylvie Robbe-Dubois, F. Bettonvil, P. Berio, R. Navarro, U. Graser, U. Beckman, G. Weigelt, F. Vakili, T. Henning, J.-C. Gonzales, S. Wolf, C. Bailet, J. Behrend, Y. Bresson, O. Chesneau, J. Clausse, C. Connot, M. Dugué, Y. Fantei, E. Elswijk, H. Hanenburg, K. Hofmann, M. Heininger, R. ter Horst, J. Hron, J. Kragt, N. Tromp, T. Agocs, G. Kroes, W. Laun, Ch. Leinert, M. Lehmitz, A. Matter, J. Menut, F. Millour, U. Neumann, E. Nussbaum, S. Ottogalli, J.-U. Pott, F. Rigal, A. Roussel, D. Schertl, M. Vannier, K. Wagner, M. Mellein, T. Kroener, N. Mauclert, P. Girard, G. Lagarde, L. Mosoni, A. Jasko, A. Glindemann, T. Phan Duc, G. Finger, D. Ives, G. Jakob, I. Percheron, G. Avila, R. Palsa, Eszter Pozna, J. Lizon, Ch. Lucuix, S. Menardi, P. Haguenauer, P. Gitton, S. Morel, F. Gonté, P. Jolley, G. Rupprecht, P. Bourget, F. Delplancke, L. Mehrgan, J. Stegmeier, G. van Belle, A. Richichi, A. Moorwood

Proceedings Volume 8445, 84450R (2012) https://doi.org/10.1117/12.926238

KEYWORDS: Interferometry, Sensors, Visibility, Mid-IR, L band, Telescopes, Spectral resolution, Image restoration, Interferometers, Photometry

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Proceedings Article | 6 August 2010 Paper

Low-vibration high-cooling power 2-stage cryocoolers for ground-based astronomical instrumentation

Gerd Jakob, Jean-Louis Lizon

Proceedings Volume 7733, 77333V (2010) https://doi.org/10.1117/12.856233

KEYWORDS: Cryocoolers, Head, Cryogenics, Astronomical instrumentation, Helium, Manufacturing, Astronomy, Telescopes, Temperature sensors, Radiation effects

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Proceedings Article | 22 July 2010 Paper

Advanced high-cooling power 2-stage Gifford-McMahon refrigerator systems

Gerd Jakob, Jean-Louis Lizon

Proceedings Volume 7739, 77393I (2010) https://doi.org/10.1117/12.856231

KEYWORDS: Head, Helium, Cryocoolers, Cryogenics, Temperature metrology, Cooling systems, Standards development, Safety, Technetium, Interfaces

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Proceedings Article | 22 July 2010 Paper

A hybrid liquid nitrogen system for the cooling of the ESO OmegaCAM detector

J. L. Lizon, A. Silber, G. Jakob

Proceedings Volume 7739, 77393H (2010) https://doi.org/10.1117/12.856095

KEYWORDS: Sensors, Nitrogen, Cooling systems, Liquids, Cryogenics, Telescopes, Charge-coupled devices, CCD image sensors, Cameras, Space telescopes

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Proceedings Article | 21 July 2010 Paper

Upgrade of VISIR the mid-infrared instrument at the VLT

F. Kerber, H. Kaeufl, M. van den Ancker, P. Baksai, D. Dubreuil, G. Durand, D. Dobrzycka, G. Finger, Ch. Hummel, D. Ives, G. Jakob, E. Lagadec, L. Lundin, G. Marconi, M. Moerchen, Y. Momany, D. Nuernberger, E. Pantin, M. Riquelme, R. Siebenmorgen, A. Smette, L. Venema, U. Weilenmann, I. Yegorova

Proceedings Volume 7735, 77357R (2010) https://doi.org/10.1117/12.857368

KEYWORDS: Sensors, Mid-IR, Telescopes, Astronomy, Observatories, Spectrographs, Infrared radiation, Coronagraphy, Spectral resolution, Infrared telescopes

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The European Southern Observatory (ESO) is preparing to upgrade VISIR, the mid-IR imager and spectrograph at the VLT. The project team is comprised of ESO staff and members of the original consortium that built VISIR: CEA Saclay and ASTRON. The goal is to enhance the scientific performance of VISIR and to facilitate its use by the ESO community. In order to capture the needs of the user community, we collected input from the users by means of a webbased questionnaire. In line with the results of the internal study and the input from the user community, the upgrade plan calls for a combination measures: installation of improved hardware, optimization of instrument operations and software support. The limitations of the current detector (sensitivity, cosmetics, artifacts) have been known for some time and a new 1k x 1k Si:As Aquarius array (Raytheon) will be the cornerstone of the VISIR upgrade project. A modified spectroscopic mode will allow covering the N-band in a single observation. Several new scientific modes (e.g., polarimetry, coronagraphy) will be implemented on a best effort basis. In addition, the VISIR operational scheme will be enhanced to ensure that optimal use of the observing conditions will be made. Specifically, we plan to provide a means to monitor precipitable water vapour (PWV) and enable the user to specify it as a constraint set for service mode observations. In some regions of the mid-IR domain, the amount of PWV has a fundamental effect on the quality of a given night for mid-IR astronomy. The plan also calls for full support by ESO pipelines that will deliver science-ready data products. Hence the resulting files will provide physical units and error information and all instrumental signatures will have been removed. An upgraded VISIR will be a powerful instrument providing diffraction-limited performance at an 8-m telescope. Its improved performance and efficiency as well as new science capabilities will serve the needs of the ESO community but will also offer synergy with various other facilities such as ALMA, JWST, VLTI and SOFIA. A wealth of targets for detailed study will be available from survey work done by VISTA and WISE. Finally, the upgraded VISIR will also serve as a pathfinder for potential mid-IR instrumentation at the European Extremely Large Telescope (E-ELT) in terms of technology as well as operations.

Proceedings Article | 20 July 2010 Paper

Different ways of reducing vibrations induced by cryogenic instruments

J. L. Lizon, G. Jakob, B. de Marneffe, A. Preumont

Proceedings Volume 7739, 77394B (2010) https://doi.org/10.1117/12.856020

KEYWORDS: Head, Cryogenics, Current controlled current source, Actuators, Sensors, Telescopes, Control systems, Nitrogen, Infrared radiation, Spectrographs

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Proceedings Article | 20 July 2010 Paper

Ultrastable operation of detectors for high-resolution spectrographs

Antonio Manescau, Marco Gullieuszik, Olaf Iwert, Hans Dekker, Jean-Louis Lizon, Gaspare Lo Curto, Peter Sinclaire, Filippo Maria Zerbi, Gerd Jakob, Dario Sosa, Paola Amico, Luca Pasquini

Proceedings Volume 7739, 77394C (2010) https://doi.org/10.1117/12.856829

KEYWORDS: Sensors, Spectrographs, Charge-coupled devices, Sensor performance, Calibration, Velocity measurements, Detector development, Spectral resolution, Environmental sensing, Computing systems

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Proceedings Article | 6 July 2006 Paper

Development of a GaAs-based BIB detector for sub-mm wavelengths

L. Reichertz, J. Beeman, B. Cardozo, G. Jakob, R. Katterloher, N. Haegel, E. Haller

Proceedings Volume 6275, 62751S (2006) https://doi.org/10.1117/12.673039

KEYWORDS: Gallium arsenide, Sensors, Doping, Photoresistors, Absorption, Semiconducting wafers, Detector development, Germanium, Multilayers, Interfaces

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Proceedings Article | 20 October 2005 Paper

A new optical metrology tool for measuring aspheres

Gerd Jakob, Matthias Meyer, Thomas Fries

Proceedings Volume 5965, 59651Z (2005) https://doi.org/10.1117/12.625534

KEYWORDS: Aspheric lenses, Metrology, Sensors, Head, Spherical lenses, Optical metrology, Optical spheres, Computer generated holography, Colorimetry, 3D metrology

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Proceedings Article | 29 August 2005 Paper

First results on GaAs blocked impurity band (BIB) structures for far-infrared detector arrays

L. Reichertz, B. Cardozo, J. Beeman, D. Larsen, S. Tschanz, G. Jakob, R. Katterloher, N. Haegel, E. Haller

Proceedings Volume 5883, 58830Q (2005) https://doi.org/10.1117/12.620156

KEYWORDS: Gallium arsenide, Doping, Sensors, Photoresistors, Liquid phase epitaxy, Detector arrays, Absorption, Sulfur, Carbon, Far infrared

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Proceedings Article | 4 November 2004 Paper

GaAs BIB photodetector development for far-infrared astronomy

Lothar Reichertz, Jeffrey Beeman, Benjamin Cardozo, Nancy Haegel, Eugene Haller, Gerd Jakob, Reinhard Katterloher

Proceedings Volume 5543, (2004) https://doi.org/10.1117/12.560291

KEYWORDS: Gallium arsenide, Sensors, Doping, Absorption, Liquid phase epitaxy, Photoresistors, Astronomy, Silicon, Detector arrays, Germanium

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Proceedings Article | 8 April 2004 Paper

Terahertz calorimetry: an absolute power meter for terahertz radiation and the absorptivity of the Herschel Space Observatory telescope mirror coating

Tjeerd Klaassen, J. Niels Hovenier, Jacqueline Fischer, Gerd Jakob, Albrecht Poglitsch, Oren Sternberg

Proceedings Volume 5354, (2004) https://doi.org/10.1117/12.526994

KEYWORDS: Terahertz radiation, Power meters, Mirrors, Silicon carbide, Coating, Space telescopes, Bidirectional reflectance transmission function, Absorption, Telescopes, Sensors

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Proceedings Article | 5 March 2003 Paper

Scattering of sub-millimeter radiation from rough surfaces: absorbers and diffuse reflectors for HIFI and PACS

Tjeerd Klaassen, John Blok, J. Niels Hovenier, Gerd Jakob, Dirk Rosenthal, Klaas Wildeman

Proceedings Volume 4850, (2003) https://doi.org/10.1117/12.461566

KEYWORDS: Specular reflections, Reflection, Silicon carbide, Scattering, Absorption, Light scattering, Polarization, Surface roughness, Foam, Bidirectional reflectance transmission function

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Proceedings Article | 8 February 2002 Paper

Liquid phase epitaxy centrifuge for growth of ultrapure gallium arsenide for far-infrared photoconductors

Reinhard Katterloher, Gerd Jakob, Mitsuharu Konuma, Alfred Krabbe, Nancy Haegel, S. Samperi, Jeffrey Beeman, Eugene Haller

Proceedings Volume 4486, (2002) https://doi.org/10.1117/12.455132

KEYWORDS: Gallium arsenide, Liquid phase epitaxy, Sensors, Doping, Gallium, Infrared sensors, Photoresistors, Silicon, Absorption, Far infrared

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Proceedings Article | 28 July 2000 Paper

32-pixel FIRGA demonstrator: testing of a gallium arsenide photoconductor array for far-infrared astronomy

Reinhard Katterloher, Lothar Barl, Gerd Jakob, Mitsuharu Konuma, Eugene Haller, Otto Frenzl, Lou Hermans

Proceedings Volume 4013, (2000) https://doi.org/10.1117/12.393991

KEYWORDS: Gallium arsenide, Sensors, Liquid phase epitaxy, Photoresistors, Tellurium, Silicon, Astronomy, Cryogenics, Gallium, Electronics

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Proceedings Article | 21 August 1998 Paper

4x32 FIRGA array: a pacesetter for a 52x32-element gallium arsenide focal plane array

Reinhard Katterloher, Lothar Barl, Jeffrey Beeman, Erwin Czech, Detlef Engemann, Otto Frenzl, Nancy Haegel, Eugene Haller, Thomas Henning, Lou Hermans, Gerd Jakob, Mitsuharu Konuma, Goeran Pilbratt

Proceedings Volume 3354, (1998) https://doi.org/10.1117/12.317301

KEYWORDS: Sensors, Gallium arsenide, Infrared sensors, Cryogenics, Electronics, Photoresistors, Liquid phase epitaxy, Interfaces, Doping, Far infrared

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Proceedings Article | 21 August 1998 Paper

FIRSA: the demonstrator array of the FIR camera for the photoconductor instrument PACS on ESA's FIRST satellite

Dietrich Lemke, Lothar Barl, S. Eckardt, Otto Frenzl, Ulrich Groezinger, Lou Hermans, Gerd Jakob, Reinhard Katterloher, Albrecht Poglitsch, Joost Seijnaeve, Juergen Wolf

Proceedings Volume 3354, (1998) https://doi.org/10.1117/12.317247

KEYWORDS: Chromium, Sensors, Cameras, Picture Archiving and Communication System, Manufacturing, Photoresistors, Capacitors, Satellites, Electronics, Spectroscopy

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Proceedings Article | 29 September 1995 Paper

Recent results from the development of a far-infrared n-type GaAs detector array for FIRST

Reinhard Katterloher, Gerd Jakob, Elisabeth Bauser, S. Zehender, Eugene Haller, Jeffrey Beeman, Thomas Henning, Goeran Pilbratt

Proceedings Volume 2553, (1995) https://doi.org/10.1117/12.221382

KEYWORDS: Sensors, Gallium arsenide, Photoresistors, Detector development, Liquid phase epitaxy, Silicon, Detector arrays, Signal detection, Space telescopes, Photodetectors

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Proceedings Article | 6 June 1995 Paper

Development of a far-infrared detector array for FIRST based on n-type ultrapure liquid phase epitaxial gallium arsenide

Reinhard Katterloher, Gerd Jakob, Elisabeth Bauser, Eugene Haller, Thomas Henning, Goeran Pilbratt

Proceedings Volume 2475, (1995) https://doi.org/10.1117/12.211243

KEYWORDS: Gallium arsenide, Sensors, Liquid phase epitaxy, Photoresistors, Silicon, Detector development, Detector arrays, Contamination, Space telescopes, Far infrared

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