Dr. Benjamin Greiner Profile

Dr. Benjamin Greiner

Structural Dynamics and IT Infrastructure at Uni Stuttgart

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Author

Publications (8)

Proceedings Article | 13 December 2020 Presentation + Paper

Reactivation of the active mass damping system for SOFIA to improve image stability

Benjamin Greiner, Rick Brewster, Anja Mrzyglod, Jörg Wagner

Proceedings Volume 11445, 114450W (2020) https://doi.org/10.1117/12.2561373

KEYWORDS: Telescopes, Mirrors, Observatories, Infrared astronomy, Astronomical telescopes, Carbon, Structured optical fibers, Turbulence, Control systems, Actuators

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Proceedings Article | 6 July 2018 Presentation + Paper

A new finite element model of the SOFIA primary mirror cell to investigate dynamical behavior

Benjamin Greiner, Bernhard Malicek, Michael Lachenmann, Alfred Krabbe, Jörg Wagner

Proceedings Volume 10700, 107000K (2018) https://doi.org/10.1117/12.2311997

KEYWORDS: Mirrors, Finite element methods, Telescopes, Observatories, Optical aberrations, Infrared astronomy, Geometrical optics, Manufacturing

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Proceedings Article | 27 July 2016 Paper

A new test environment for the SOFIA secondary mirror assembly to reduce the required time for in-flight testing

Yannick Lammen, Andreas Reinacher, Rick Brewster, Benjamin Greiner, Friederike Graf, Alfred Krabbe

Proceedings Volume 9906, 99064T (2016) https://doi.org/10.1117/12.2232152

KEYWORDS: Actuators, Mirrors, Observatories, Cameras, Telescopes, Shape memory alloys, Sensors, Position sensors, Aluminum, Manufacturing

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The Stratospheric Observatory For Infrared Astronomy (SOFIA) reached its full operational capability in 2014 and takes off from the NASA Armstrong Flight Research Center to explore the universe about three times a week. Maximizing the program's scientific output naturally leaves very little flight time for implementation and test of improved soft- and hardware. Consequently, it is very important to have a comparable test environment and infrastructure to perform troubleshooting, verifications and improvements on ground without interfering with science missions. SOFIA's Secondary Mirror Mechanism is one of the most complex systems of the observatory. In 2012 a first simple laboratory mockup of the mechanism was built to perform basic controller tests in the lower frequency band of up to 50Hz. This was a first step to relocate required engineering tests from the active observatory into the laboratory. However, to test and include accurate filters and damping methods as well as to evaluate hardware modifications a more precise mockup is required that represents the system characteristics over a much larger frequency range. Therefore the mockup has been improved in several steps to a full test environment representing the system dynamics with high accuracy. This new ground equipment allows moving almost the entire secondary mirror test activities away from the observatory. As fast actuator in the optical path, the SMM also plays a major role in SOFIA's pointing stabilization concept. To increase the steering bandwidth, hardware changes are required that ultimately need to be evaluated using the telescope optics. One interesting concept presented in this contribution is the in- stallation of piezo stack actuators between the mirror and the chopping mechanism. First successful baseline tests are presented. An outlook is given about upcoming performance tests of the actively controlled piezo stage with local metrology and optical feedback. To minimize the impact on science time, the laboratory test setup will be expanded with an optical measurement system so that it can be used for the vast majority of testing.

Proceedings Article | 27 July 2016 Paper

Characterization of the mechanical properties of the SOFIA secondary mirror mechanism in a multi-stage approach

Benjamin Greiner, Yannick Lammen, Andreas Reinacher, Alfred Krabbe, Jörg Wagner

Proceedings Volume 9906, 99063R (2016) https://doi.org/10.1117/12.2231648

KEYWORDS: Mirrors, Finite element methods, Observatories, Telescopes, Infrared astronomy, Hardware testing, Sensors, Data modeling, Motion models, Actuators

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Proceedings Article | 22 July 2014 Paper

The integrated motion measurement simulation for SOFIA

Prashant Kaswekar, Benjamin Greiner, Jörg Wagner

Proceedings Volume 9145, 91454F (2014) https://doi.org/10.1117/12.2054900

KEYWORDS: Telescopes, Mirrors, Sensors, Space telescopes, Motion measurement, Motion models, Device simulation, Motion estimation, Observatories, Gyroscopes

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Proceedings Article | 21 February 2008 Paper

Single molecule detection for in vitro diagnostics

Thomas Kirner, Jörg Ackermann, Harald Mathis, Benjamin Greiner, Thomas Tonn, David Tschachojan, Natasa Kukoc-Zivojnov, Sebastian Giehring

Proceedings Volume 6862, 68620H (2008) https://doi.org/10.1117/12.763637

KEYWORDS: Molecules, Fluorescence correlation spectroscopy, Glasses, Luminescence, In vitro testing, Confocal microscopy, Biological research, Fluorescence spectroscopy, Diagnostics, Stochastic processes

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Proceedings Article | 21 February 2008 Paper

Integrated microfluidic diagnostic platform for marker and environmental detection

Harald Mathis, Christian Müller, Benjamin Greiner, Guido Blaess

Proceedings Volume 6862, 68620G (2008) https://doi.org/10.1117/12.762683

KEYWORDS: Microfluidics, Diagnostics, Molecules, Sensors, Nanocrystals, Signal detection, Particles, Silicon, Semiconductors, Gold

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Proceedings Article | 21 February 2008 Paper

Single molecules in fluorescence fluctuation spectroscopy: effective volume and photon counting histogram

Jörg Ackermann, Harald Mathis, Benjamin Greiner

Proceedings Volume 6862, 686204 (2008) https://doi.org/10.1117/12.763904

KEYWORDS: Molecules, Photon counting, Probability theory, Luminescence, Particles, Stochastic processes, Fluorescence correlation spectroscopy, Diffusion, Fluorescence spectroscopy, Spectroscopy

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Showing 5 of 8 publications

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