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Selection of the correct convergence angle is essential for achieving the highest resolution imaging in scanning transmission electron microscopy (STEM). Use of poor heuristics, such as Rayleigh's quarter-phase rule, to assess probe quality…

Data Analysis, Statistics and Probability · Physics 2020-10-29 Noah Schnitzer , Suk Hyun Sung , Robert Hovden

In the field of beam physics, two frontier topics have taken center stage due to their potential to enable new approaches to discovery in a wide swath of science. These areas are: advanced, high gradient acceleration techniques, and x-ray…

This paper presents a framework for developing a live vision-correcting display (VCD) to address refractive visual aberrations without the need for traditional vision correction devices like glasses or contact lenses, particularly in…

Image and Video Processing · Electrical Eng. & Systems 2025-01-06 Akhilesh Balaji , Dhruv Ramu

Self-seeding schemes, consisting of two undulators with a monochromator in between, aim to reduce the bandwidth of SASE X-ray FELs. We recently proposed a new method of monochromatization exploiting a single crystal in Bragg-transmission…

Accelerator Physics · Physics 2015-05-20 Gianluca Geloni , Vitali Kocharyan , Evgeni Saldin

X-ray Absorption Spectroscopy (XAS) is a widely used X-ray diagnostic method. While synchrotrons have large communities of XAS users, its use on X-Ray Free Electron Lasers (XFEL) facilities has been rather limited. At a first glance, the…

Instrumentation and Detectors · Physics 2020-05-05 M. Harmand , M. Cammarata , M. Chollet , A. G Krygier , H. T. Lemke , D. Zhu

Wavelength calibration is a routine and critical part of any spectral work-flow, but many astronomers still resort to matching detected peaks and emission lines by hand. We present RASCAL (RANSAC Assisted Spectral CALibration), a python…

Instrumentation and Methods for Astrophysics · Physics 2019-12-13 Josh Veitch-Michaelis , Marco C Lam

Automation underpins progress across scientific and industrial disciplines. Yet, automating tasks requiring interpretation of abstract visual information remain challenging. For example, crystal alignment strongly relies on humans with the…

Machine Learning · Computer Science 2026-04-14 J. Oppliger , M. Stifter , A. Rüegg , I. Biało , L. Martinelli , P. G. Freeman , D. Prabhakaran , J. Zhao , Q. Wang , J. Chang

The next generation of extreme adaptive optics (AO) must be calibrated exceptionally well to achieve the desired contrast for ground-based direct imaging exoplanet targets. Current wavefront sensing and control system responses deviate from…

The X-ray free-electron laser oscillator (XFELO) has recently been reconsidered a promising candidate for producing high-brightness, fully coherent pulses in the hard X-ray regime. This letter proposes a gain-guided XFELO scheme, avoiding…

Accelerator Physics · Physics 2018-08-29 Kai Li , Haixiao Deng

Diffractive lenses have recently been applied to the domain of multispectral imaging in the X-ray and UV regimes where they can achieve very high resolution as compared to reflective and refractive optics. Conventionally, spectral…

Image and Video Processing · Electrical Eng. & Systems 2020-05-26 Evan Widloski , Ulas Kamaci , Farzad Kamalabadi

The successful operation of the hard x-ray self-seeding experiment at the LCLS opens the era of fully coherent hard x-ray free electron lasers (FELs). However, the shot-to-shot radiation fluctuation is still a serious issue. In this paper,…

Accelerator Physics · Physics 2013-05-07 Haixiao Deng , Chao Feng

The operation of an inverse-Compton scattering source of x-rays or gamma-rays requires the precision alignment and synchronization of highly focused electron bunches and laser pulses at the collision point. The arrival times of electron and…

Accelerator Physics · Physics 2015-06-19 Michael R. Hadmack , Eric B. Szarmes , John M. J. Madey , Jeremy M. D. Kowalczyk

Online reinforcement learning (RL) is increasingly used for realizing adaptive systems in the presence of design time uncertainty. Online RL facilitates learning from actual operational data and thereby leverages feedback only available at…

Software Engineering · Computer Science 2023-07-11 Andreas Metzger , Jan Laufer , Felix Feit , Klaus Pohl

In industrial X-ray Computed Tomography (CT), the need for rapid in-line inspection is critical. Sparse-angle tomography plays a significant role in this by reducing the required number of projections, thereby accelerating processing and…

Computer Vision and Pattern Recognition · Computer Science 2025-05-27 Tianyuan Wang , Felix Lucka , Daniël M. Pelt , K. Joost Batenburg , Tristan van Leeuwen

We demonstrate that a common-line method can assemble a 3D oversampled diffracted intensity distribution suitable for high-resolution structure solution from a set of measured 2D diffraction patterns, as proposed in experiments with an…

Biomolecules · Quantitative Biology 2007-10-16 V. L. Shneerson , A. Ourmazd , D. K. Saldin

We study online alignment of large language models under misspecified preference feedback, where the observed preference oracle deviates from an ideal but unknown ground-truth oracle. The online LLM alignment problem is a bi-level…

Machine Learning · Computer Science 2026-02-25 Zimeng Li , Mudit Gaur , Vaneet Aggarwal

X-ray near-field speckle-based phase-sensing approaches provide efficient means to characterise optical elements. Here, we present a theoretical review of several of these speckle methods in the frame of optical characterisation and provide…

The X-ray free electron lasers (XFEL) can enable diffractive structural determination of protein crystals or single molecules that are too radiation-sensitive for conventional X-ray analysis. However the electronic form factor could have…

Quantum Physics · Physics 2017-01-30 Zheng Li , Nikita Medvedev , Henry Chapman , Yanhua Shih

Reinforcement Learning (RL) presents a new approach for controlling Adaptive Optics (AO) systems for Astronomy. It promises to effectively cope with some aspects often hampering AO performance such as temporal delay or calibration errors.…

Instrumentation and Methods for Astrophysics · Physics 2021-05-19 Jalo Nousiainen , Chang Rajani , Markus Kasper , Tapio Helin

Aberration correction is an important aspect of modern high-resolution scanning transmission electron microscopy. Most methods of aligning aberration correctors require specialized sample regions and are unsuitable for fine-tuning…