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arXiv · 2208.11250

An Online Dynamic Amplitude-Correcting Gradient Estimation Technique to Align X-ray Focusing Optics

Sean Breckling·Leora E. Dresselhaus-Marais·Eric Machorro·Michael C. Brennan·Jordan Pillow·Malena Espanol·Bernard Kozioziemski·Ryan Coffee·Sunam Kim·Sangsoo Kim·Daewoong Nam·Arnulfo Gonzales·Margaret Lund·Jesse Adams·Daniel Champion·Ajanae Williams·Kevin Joyce·Marylesa Howard
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Abstract

High-brightness X-ray pulses, as generated at synchrotrons and X-ray free electron lasers (XFEL), are used in a variety of scientific experiments. Many experimental testbeds require optical equipment, e.g Compound Refractive Lenses (CRLs), to be precisely aligned and focused. The lateral alignment of CRLs to a beamline requires precise positioning along four axes: two translational, and the two rotational. At a synchrotron, alignment is often accomplished manually. However, XFEL beamlines present a beam brightness that fluctuates in time, making manual alignment a time-consuming endeavor. Automation using classic stochastic methods often fail, given the errant gradient estimates. We present an online correction based on the combination of a generalized finite difference stencil and a time-dependent sampling pattern. Error expectation is analyzed, and efficacy is demonstrated. We provide a proof of concept by laterally aligning optics on a simulated XFEL beamline.

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Sean Breckling, Leora E. Dresselhaus-Marais, Eric Machorro, Michael C. Brennan, Jordan Pillow, Malena Espanol, Bernard Kozioziemski, Ryan Coffee, Sunam Kim, Sangsoo Kim, Daewoong Nam, Arnulfo Gonzales, Margaret Lund, Jesse Adams, Daniel Champion, Ajanae Williams, Kevin Joyce, Marylesa Howard. 2022-08-24. An Online Dynamic Amplitude-Correcting Gradient Estimation Technique to Align X-ray Focusing Optics. https://arxiv.org/abs/2208.11250

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