Mr. Patrick A. Roman Profile

Patrick A. Roman

Microsystems Engineer at NASA Goddard Space Flight Ctr

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Publications (7)

Proceedings Article | 21 September 2011 Paper

Fabrication and test of an optical magnetic mirror

John Hagopian, Patrick Roman, Shahram Shiri, Edward Wollack, Madhumita Roy

Proceedings Volume 8096, 80963W (2011) https://doi.org/10.1117/12.903925

KEYWORDS: Mirrors, Magnetism, Diffraction, Dielectric polarization, Control systems, Semiconducting wafers, Dielectrics, Phase shifts, Nanostructures, Nanowires

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Proceedings Article | 31 August 2010 Paper

Multiwalled carbon nanotubes for stray light suppression in space flight instruments

John Hagopian, Stephanie Getty, Manuel Quijada, June Tveekrem, Ron Shiri, Patrick Roman, James Butler, Georgi Georgiev, Jeff Livas, Cleophus Hunt, Alejandro Maldonado, Saikat Talapatra, Xianfeng Zhang, Stergios Papadakis, Andrew Monica, David Deglau

Proceedings Volume 7761, 77610F (2010) https://doi.org/10.1117/12.864386

KEYWORDS: Stray light, Mirrors, Reflectivity, Carbon nanotubes, Silicon, Bidirectional reflectance transmission function, Aerospace engineering, Nanoimprint lithography, Stray light control, Light scattering

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Observations of the Earth are extremely challenging; its large angular extent floods scientific instruments with high flux within and adjacent to the desired field of view. This bright light diffracts from instrument structures, rattles around and invariably contaminates measurements. Astrophysical observations also are impacted by stray light that obscures very dim objects and degrades signal to noise in spectroscopic measurements. Stray light is controlled by utilizing low reflectance structural surface treatments and by using baffles and stops to limit this background noise. In 2007 GSFC researchers discovered that Multiwalled Carbon Nanotubes (MWCNTs) are exceptionally good absorbers, with potential to provide order-of-magnitude improvement over current surface treatments and a resulting factor of 10,000 reduction in stray light when applied to an entire optical train. Development of this technology will provide numerous benefits including: a.) simplification of instrument stray light controls to achieve equivalent performance, b.) increasing observational efficiencies by recovering currently unusable scenes in high contrast regions, and c.) enabling low-noise observations that are beyond current capabilities. Our objective was to develop and apply MWCNTs to instrument components to realize these benefits. We have addressed the technical challenges to advance the technology by tuning the MWCNT geometry using a variety of methods to provide a factor of 10 improvement over current surface treatments used in space flight hardware. Techniques are being developed to apply the optimized geometry to typical instrument components such as spiders, baffles and tubes. Application of the nanostructures to alternate materials (or by contact transfer) is also being investigated. In addition, candidate geometries have been tested and optimized for robustness to survive integration, testing, launch and operations associated with space flight hardware. The benefits of this technology extend to space science where observations of extremely dim objects require suppression of stray light.

Proceedings Article | 12 May 2009 Paper

Integration of a carbon nanotube field emission electron gun for a miniaturized time-of-flight mass spectrometer

Stephanie Getty, Mary Li, Larry Hess, Nick Costen, Todd King, Patrick Roman, William Brinckerhoff, Paul Mahaffy

Proceedings Volume 7318, 731816 (2009) https://doi.org/10.1117/12.818939

KEYWORDS: Ionization, Ions, Silicon, Spectroscopy, Carbon nanotubes, Semiconducting wafers, Electron beams, Sensors, Ceramics, Chemical elements

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Proceedings Article | 30 April 2008 Paper

Simulation of a miniature, low-power time-of-flight mass spectrometer for in situ analysis of planetary atmospheres

Todd King, Stephanie Getty, Patrick Roman, Federico Herrero, Hollis Jones, Duncan Kahle, Bernard Lynch, George Suárez, William Brinckerhoff, Paul Mahaffy

Proceedings Volume 6959, 69590E (2008) https://doi.org/10.1117/12.780113

KEYWORDS: Ions, Sensors, Electrodes, Ionization, Spectroscopy, Prototyping, Microchannel plates, Charged particle optics, Device simulation, Electron beams

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Proceedings Article | 30 April 2008 Paper

Effect of nitrogen gas on the lifetime of carbon nanotube field emitters for electron-impact ionization mass spectrometry

Stephanie Getty, Rachael Bis, Stacy Snyder, Emily Gehrels, Kristina Ramirez, Todd King, Patrick Roman, Paul Mahaffy

Proceedings Volume 6959, 695907 (2008) https://doi.org/10.1117/12.776914

KEYWORDS: Carbon nanotubes, Ionization, Mass spectrometry, Nitrogen, Iron, Ions, Silicon, Spectroscopy, Sputter deposition, Interference (communication)

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Proceedings Article | 30 April 2008 Paper

A miniature MEMS and NEMS enabled time-of-flight mass spectrometer for investigations in planetary science

P. Roman, S. Getty, F. Herrero, R. Hu, H. Jones, D. Kahle, T. King, P. Mahaffy

Proceedings Volume 6959, 69590G (2008) https://doi.org/10.1117/12.777670

KEYWORDS: Ions, Microelectromechanical systems, Spectroscopy, Silicon, Nanoelectromechanical systems, Ionization, Prototyping, Sensors, Carbon nanotubes, Semiconducting wafers

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Proceedings Article | 3 May 2007 Paper

Performance of a carbon nanotube field emission electron gun

Stephanie Getty, Todd King, Rachael Bis, Hollis Jones, Federico Herrero, Bernard Lynch, Patrick Roman, Paul Mahaffy

Proceedings Volume 6556, 655618 (2007) https://doi.org/10.1117/12.720995

KEYWORDS: Electrodes, Electron beams, Carbon nanotubes, Beam shaping, Picosecond phenomena, Silicon, Spectroscopy, Power supplies, Dielectrics, Image processing

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Showing 5 of 7 publications

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