Dr. Larry D. Gardner Profile

Dr. Larry D. Gardner

Physicist at Harvard-Smithsonian Ctr for Astrophysics

SPIE Involvement:

Author

Proceedings Article | 25 August 2005 Paper

Ultraviolet spectroscopy of solar energetic particle source regions

J. Kohl, S. Cranmer, R. Esser, L. Gardner, S. Fineschi, J. Lin, A. Panasyuk, J. Raymond, L. Strachan

Proceedings Volume 5901, 590111 (2005) https://doi.org/10.1117/12.620821

KEYWORDS: Curium, Coronagraphy, Magnetism, Ultraviolet radiation, Particles, Electrons, Plasma, Diagnostics, Spectrometers, Mirrors

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Proceedings Article | 14 February 2003 Paper

Advanced Spectroscopic and Coronagraphic Explorer: science payload design concept

Larry Gardner, John Kohl, Peter Daigneau, Peter Smith, Leonard Strachan, Russell Howard, Dennis Socker, Joseph Davila, Giancarlo Noci, Marco Romoli, Silvano Fineschi

Proceedings Volume 4843, (2003) https://doi.org/10.1117/12.466139

KEYWORDS: Mirrors, Coronagraphy, Sensors, Charge-coupled devices, Telescopes, Spectroscopy, Polarimetry, Solar processes, Microchannel plates, Spectroscopes

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Proceedings Article | 18 December 2000 Paper

Efficiency variations of UVCS/SOHO based on laboratory measurements of replica gratings

Larry Gardner, Nigel Atkins, Silvano Fineschi, Peter Smith, John Kohl, L. Maccari, Marco Romoli

Proceedings Volume 4139, (2000) https://doi.org/10.1117/12.410542

KEYWORDS: Mirrors, Sensors, Telescopes, Diffraction gratings, Spectroscopy, Solids, Vignetting, Krypton, Calibration, Diffraction

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Proceedings Article | 25 November 1999 Paper

Polarimetry of the UV solar corona with ASCE

Silvano Fineschi, Larry Gardner, John Kohl, Marco Romoli, Emanuele Pace, Gianni Corti, Giancarlo Noci

Proceedings Volume 3764, (1999) https://doi.org/10.1117/12.371079

KEYWORDS: Polarimetry, Polarization, Polarizers, Magnetism, Ultraviolet radiation, Coronagraphy, Stray light, Solar processes, Spectroscopy, Mirrors

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The Advanced Solar Coronal Explorer (ASCE) is a mid-explorer (MidEx) mission selected, together with other five, for the a Phase A Concept Study in the 1999 round of MidEX proposal. ASCE's spacecraft bus is a SPARTAN 400 reusable carrier deployed in low Earth orbit by the Space Shuttle. ASCE's payload comprises two instrument modules, the Spectroscopic and Polarimetric Coronagraph (SPC) and the Extreme Ultraviolet Imager (EUVI). The scientific objective of the mission is the investigation, through spectroscopic and polarimetric techniques, of the physics of the coronal heating and of the solar wind acceleration. A critical physical parameter of the corona is the magnetic field. Polarimetric measurements of UV coronal radiation and their interpretation through the Hanle effect can be used for coronal magnetic field diagnostics. One of the SPC spectrometers, the Spectroscopy/Polarimetry channel (SPCH), includes a reflecting Brewster-angle polarimeter for measurements of the linear polarization of the HI Lyman series lines (i.e., Ly-(alpha) , -(beta) , and (gamma) ) and of the O VI 1032 Angstrom line. In this paper, the optical design of the SPCH polarimeter is described. A relevant element of this design is the external occulter (EXO) that is supported on a boom, which is extended 10 m beyond the instrument aperture, once the instrument is in station. The analysis of the stray- light reduction provided by this occulting system is described in this paper. The principal source of stray light is solar disk light that is diffracted from the edge of the EXO and scattered from the telescope mirror. The analysis shows that the stray-light is less than 10^-2 the coronal signal. This level of stray-light rejection minimizes the polarized stray light that may be introduced by the EXO's straight edge. The most appropriate material for the polarizer has been found to be CaF₂. The material selection criteria are described. Finally, the paper illustrates with an example that if the linear polarization can be measured better than 1%, then the instrumental sensitivity to magnetic fields may reach a few gauss (greater than 2 gauss), in coronal active regions.

Proceedings Article | 25 November 1999 Paper

Flat field of UVCS detectors for early part of SOHO mission

Mario Cosmo, Peter Smith, Nigel Atkins, R. Suleiman, Larry Gardner, John Kohl

Proceedings Volume 3764, (1999) https://doi.org/10.1117/12.371094

KEYWORDS: Sensors, Light scattering, Stars, Ultraviolet radiation, Spectroscopy, Coronagraphy, Solar processes, Light, Observatories, Telescopes

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Proceedings Article | 25 November 1999 Paper

Optical configurations for the EUV channels of the Advanced Solar Coronal Explorer mission

Luca Poletto, Giampiero Naletto, Piergiorgio Nicolosi, Giuseppe Tondello, Larry Gardner

Proceedings Volume 3764, (1999) https://doi.org/10.1117/12.371096

KEYWORDS: Sensors, Diffraction gratings, Extreme ultraviolet, Spectroscopy, Channel projecting optics, Solar processes, Diffraction, Tellurium, Polarimetry, Spherical lenses

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Proceedings Article | 25 November 1999 Paper

Advanced Solar Coronal Explorer mission (ASCE)

Larry Gardner, John Kohl, S. Cranmer, Silvano Fineschi, Leon Golub, John Raymond, Peter Smith, Leonard Strachan, Russell Howard, J. Daniel Moses, Dennis Socker, Dennis Wang, Richard Fisher, Joseph Davila, C. St. Cyr, Giancarlo Noci, Marco Romoli, Giuseppe Tondello, Giampiero Naletto, Piergiorgio Nicolosi, Luca Poletto

Proceedings Volume 3764, (1999) https://doi.org/10.1117/12.371095

KEYWORDS: Mirrors, Coronagraphy, Polarimetry, Spectroscopy, Telescopes, Solar processes, Sensors, Space telescopes, Spectroscopes, Extreme ultraviolet

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The Advanced Solar Coronal Explorer (ASCE) is one of five missions selected for a Phase A Concept Study in the current round of proposed MIDEX missions. ASCE's instrument complement is supported by a SPARTAN 400 reusable carrier. The spacecraft is carried into orbit and deployed by the Space Shuttle; at mission's end, nominally 2 years later, it is retrieved and returned to earth for post-flight calibration. ASCE comprises two instrument modules, the Spectroscopic and Polarimetric Coronagraph (SPC) and the Extreme Ultraviolet Imager (EUVI). The external occulter for the coronagraph is supported on a boom, which is extended 10 meters beyond the instrument apertures once the spacecraft is on station. Large aperture optics can therefore be used, and this, in combination with improvements in optical and photon detection efficiencies, will provide spectroscopy of the extended solar corona with unprecedented sensitivity and spatial resolution, routine measurements of the electron temperature, and polarimetry of the H I Lyman lines. SPC also extends the short wavelength limit to 28 nm. As a consequence, SPC will be able to perform the first He II 30.4 nm and He I 58.4 nm spectroscopy of the extended corona. In the visible part of the spectrum (450 - 600 nm), SPC's Large Aperture Spectroscopic Coronagraph (LASCO) channel will provide polarimetric images with 1.8 arc second resolution elements, which will allow the determination of polarized brightness of the coronal plasma. In a separate parallel channel LASCO will also provide images at single minor ion line wavelengths from which can be determined the shapes and Doppler shifts of those lines. The distant external occulter provides for major improvement in stray light suppression. The EUVI instrument will take high cadence images of the full disk and low corona at four selectable wavelengths with 0.9 arc second resolution elements. A description of the instrument design and performance capabilities is presented.

Proceedings Article | 17 December 1998 Paper

White-light stray light test of the SOHO UVCS

Douglas Leviton, Larry Gardner, Silvano Fineschi, Murzy Jhabvala, John Kohl, Marco Romoli, Giancarlo Noci

Proceedings Volume 3443, (1998) https://doi.org/10.1117/12.333613

KEYWORDS: Stray light, Mirrors, Sensors, Collimators, Sun, Spectroscopy, Telescopes, Lamps, Light, Light sources

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Proceedings Article | 17 December 1998 Paper

Far-ultraviolet and visible light scatter measurements for CVD SiC mirrors for SOHO

Douglas Leviton, Timo Saha, Larry Gardner

Proceedings Volume 3443, (1998) https://doi.org/10.1117/12.333616

KEYWORDS: Mirrors, Scatter measurement, Silicon carbide, Telescopes, Visible radiation, Chemical vapor deposition, Sensors, Light scattering, Space telescopes, Scattering

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Proceedings Article | 17 December 1998 Paper

Grating stray light analysis and control in the UVCS/SOHO

Silvano Fineschi, Larry Gardner, John Kohl, Marco Romoli, Giancarlo Noci

Proceedings Volume 3443, (1998) https://doi.org/10.1117/12.333614

KEYWORDS: Diffraction gratings, Scattering, Ultraviolet radiation, Point spread functions, Spectroscopy, Solar processes, Coronagraphy, Telescopes, Temperature metrology, Surface finishing

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Proceedings Article | 8 November 1996 Paper

Stray light, radiometric, and spectral characterization of UVCS/SOHO: laboratory calibration and flight performance

Larry Gardner, John Kohl, Peter Daigneau, E. Dennis, Silvano Fineschi, J. Michels, George Nystrom, Alexander Panasyuk, John Raymond, D. Reisenfeld, Peter Smith, Leonard Strachan, R. Suleiman, Giancarlo Noci, Marco Romoli, A. Ciaravella, Andrea Modigliani, Martin Huber, Ester Antonucci, C. Benna, Silvio Giordano, Giuseppe Tondello, Piergiorgio Nicolosi, Giampiero Naletto, Claudio Pernechele, D. Spadaro, Oswald Siegmund, A. Allegra, Paolo Carosso, Murzy Jhabvala

Proceedings Volume 2831, (1996) https://doi.org/10.1117/12.257187

KEYWORDS: Stray light, Mirrors, Sensors, Telescopes, Ultraviolet radiation, Calibration, Spectroscopy, Optical testing, Coronagraphy, Lamps

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Proceedings Article | 16 October 1995 Paper

Ultraviolet Coronagraph Spectrometer for the Solar and Heliospheric Observatory: instrument description and calibration overview

John Kohl, R. Esser, Larry Gardner, Shadia Habbal, Peter Daigneau, George Nystrom, John Raymond, Leonard Strachan, A. van Ballegooijen, Giancarlo Noci, Silvano Fineschi, Marco Romoli, A. Ciaravella, Andrea Modigliani, Martin Huber, Ester Antonucci, C. Benna, Silvio Giordano, Oskar von der Luehe, Giuseppe Tondello, Piergiorgio Nicolosi, Giampiero Naletto, Claudio Pernechele, J. Geiss, George Gloeckler, G. Poletto, D. Spadaro, A. Allegra, Giuseppe Basile, R. Brusa, B. Wood, Oswald Siegmund

Proceedings Volume 2517, (1995) https://doi.org/10.1117/12.224917

KEYWORDS: Spectroscopy, Coronagraphy, Calibration, Ultraviolet radiation, Observatories, Visible radiation, Polarimetry, Reflector telescopes, Ultraviolet telescopes, Telescopes

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Proceedings Article | 7 November 1994 Paper

Polarization characterization of Ly alpha holographic gratings with a triple-reflection polarizer

Marco Romoli, Silvano Fineschi, Larry Gardner, John Kohl

Proceedings Volume 2283, (1994) https://doi.org/10.1117/12.193203

KEYWORDS: Polarizers, Polarization, Holography, Diffraction gratings, Sensors, Modulation, Magnesium fluoride, Diffraction, Mirrors, Reflection

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Proceedings Article | 7 November 1994 Paper

Ultraviolet Coronagraph Spectrometer for the Solar and Heliospheric Observatory: optical testings

Silvano Fineschi, Marco Romoli, Larry Gardner, John Kohl, Giancarlo Noci, Giuseppe Tondello

Proceedings Volume 2283, (1994) https://doi.org/10.1117/12.193204

KEYWORDS: Holography, Diffraction gratings, Polarization, Diffraction, Stray light, Coronagraphy, Ultraviolet radiation, Spectroscopy, Solar processes, Sensors

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Showing 5 of 14 publications

Conference Committee Involvement (3)

Solar Physics and Space Weather Instrumentation

31 July 2005 | San Diego, California, United States

Telescopes and Instrumentation for Solar Astrophysics

7 August 2003 | San Diego, California, United States

X-Ray and Ultraviolet Polarimetry

15 July 1993 | San Diego, CA, United States

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