Mr. Gary P. Centers Profile

Gary P. Centers

Post Baccalaureate Research Fellow at Lawrence Berkeley National Lab

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Author

Area of Expertise:

precision measurement , x-ray optics , metrology , metrology instrumentation , data analysis

Publications (7)

Proceedings Article | 17 September 2018 Presentation + Paper

The ALS OSMS: Optical Surface Measuring System for high accuracy two-dimensional slope metrology with state-of-the-art x-ray mirrors

Ian Lacey, Kevan Anderson, Gary Centers, Ralf Geckeler, Gevork Gevorkyan, John Grossiord, Andreas Just, Theo Nicolot, Brian Smith, Valeriy Yashchuk

Proceedings Volume 10760, 1076002 (2018) https://doi.org/10.1117/12.2321347

KEYWORDS: Mirrors, Calibration, Metrology, X-ray optics, X-rays, Autocollimators, Gaussian filters, Sensors

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Proceedings Article | 18 January 2018 Paper

Correlation methods in optical metrology with state-of-the-art x-ray mirrors

Valeriy Yashchuk, Gary Centers, Gevork Gevorkyan, Ian Lacey, Brian Smith

Proceedings Volume 10612, 106120O (2018) https://doi.org/10.1117/12.2305441

KEYWORDS: Mirrors, Metrology, Error analysis, X-ray optics, X-rays, Sensors, Calibration, Switching, Data acquisition, Deflectometry

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The development of fully coherent free electron lasers and diffraction limited storage ring x-ray sources has brought to focus the need for higher performing x-ray optics with unprecedented tolerances for surface slope and height errors and roughness. For example, the proposed beamlines for the future upgraded Advance Light Source, ALS-U, require optical elements characterized by a residual slope error of <100 nrad (root-mean-square) and height error of <1-2 nm (peak-tovalley). These are for optics with a length of up to one meter. However, the current performance of x-ray optical fabrication and metrology generally falls short of these requirements. The major limitation comes from the lack of reliable and efficient surface metrology with required accuracy and with reasonably high measurement rate, suitable for integration into the modern deterministic surface figuring processes. The major problems of current surface metrology relate to the inherent instrumental temporal drifts, systematic errors, and/or an unacceptably high cost, as in the case of interferometry with computer-generated holograms as a reference. In this paper, we discuss the experimental methods and approaches based on correlation analysis to the acquisition and processing of metrology data developed at the ALS X-Ray Optical Laboratory (XROL). Using an example of surface topography measurements of a state-of-the-art x-ray mirror performed at the XROL, we demonstrate the efficiency of combining the developed experimental correlation methods to the advanced optimal scanning strategy (AOSS) technique. This allows a significant improvement in the accuracy and capacity of the measurements via suppression of the instrumental low frequency noise, temporal drift, and systematic error in a single measurement run. Practically speaking, implementation of the AOSS technique leads to an increase of the measurement accuracy, as well as the capacity of ex situ metrology by a factor of about four. The developed method is general and applicable to a broad spectrum of high accuracy measurements.

Proceedings Article | 19 September 2017 Presentation

X-ray optics laboratory at the ALS: current capabilities, new challenges, and tasks for further development (Conference Presentation)

Ian Lacey, Gary Centers, Gevork Gevorkyan, Sergey Nikitin, Brian Smith, Valeriy Yashchuk

Proceedings Volume 10385, 103850D (2017) https://doi.org/10.1117/12.2275565

KEYWORDS: X-ray optics, Metrology, Optical metrology, Interferometry, Microscopy, Calibration, Diffraction, Light sources, Data processing, Optical testing

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Proceedings Article | 7 September 2017 Presentation + Paper

Surface slope metrology of highly curved x-ray optics with an interferometric microscope

Gevork Gevorkyan, Gary Centers, Kateryna Polonska, Sergey Nikitin, Ian Lacey, Valeriy Yashchuk

Proceedings Volume 10385, 103850H (2017) https://doi.org/10.1117/12.2274220

KEYWORDS: X-ray optics, Interferometry, Metrology, Optical metrology, Calibration, Optics manufacturing, Data analysis, Microscopes

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Proceedings Article | 7 September 2017 Presentation + Paper

Development of a high performance surface slope measuring system for two-dimensional mapping of x-ray optics

Ian Lacey, Jérôme Adam, Gary Centers, Gevork Gevorkyan, Sergey Nikitin, Brian Smith, Valeriy Yashchuk

Proceedings Volume 10385, 103850G (2017) https://doi.org/10.1117/12.2273029

KEYWORDS: Metrology, X-ray optics, Mirrors, Nano opto mechanical systems, Calibration, Synchrotron radiation, Light sources, Diffraction, Light, Interferometry

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Proceedings Article | 8 September 2016 Presentation + Paper

New operational mode of the pencil beam interferometry based LTP

Gary Centers, Brian Smith, Valeriy Yashchuk

Proceedings Volume 9962, 996202 (2016) https://doi.org/10.1117/12.2238298

KEYWORDS: Interferometry, X-ray optics, Metrology, Calibration, Mirrors, Lawrencium, Spherical lenses, Sensors, Charge-coupled devices, Beam splitters

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Proceedings Article | 8 September 2016 Paper

Modeling surface topography of state-of-the-art x-ray mirrors as a result of stochastic polishing process: recent developments

Valeriy Yashchuk, Gary Centers, Yuri Tyurin, Anastasia Tyurina

Proceedings Volume 9962, 99620G (2016) https://doi.org/10.1117/12.2238260

KEYWORDS: Metrology, Mirrors, Surface finishing, Stochastic processes, X-rays, Modulation transfer functions, Point spread functions, Data modeling, Optical transfer functions, Electronic filtering

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Showing 5 of 7 publications

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