Primary organizers: Ross Harder, Barbara Frosik, and Wonsuk Cha

Cohere (https://cohere.readthedocs.io/en/latest/) is a software package for coherent diffraction imaging (CDI) phase retrieval. It has been developed in the context of Bragg geometry CDI (BCDI) data where a volume of reciprocal space (3D data) is measured, leading to three-dimensional images of crystalline samples. Though, one and two-dimensional data can also be treated. The Cohere workflow is developed in three python packages. The workflow is built on cohere-core, which defines the computational algorithms for phase retrieval. Cohere-ui defines the user interface for executing the workflow. Finally, cohere-beamlines implements the beamline specific components, including diffractometer and instrument geometries, data/metadata storage formats and readers, as well as unique components in the user interface for a given beamline. 

This workshop will include an introduction to BCDI, including the basic principles of the technique and how the experiments are conducted at the Advanced Photon Source. Following the technique introduction, the Cohere software package will be discussed, this will include a brief introduction to the cohere-core and cohere-beamlines package structure, followed by hands-on work using the cohere-ui. The GUI, command line interface and Jupyter notebooks will be used for exercises with data from the APS.  Participants are encouraged to bring their own data as well. Currently Cohere has full workflow support for experiments done at ESRF ID01, PetraIII P10, and APS 34-ID-C and 1-ID-E. There is currently development level support for PAL-XFEL, EuXFEL MID and APS 8-ID and 20-ID. Without full support in the cohere-beamlines module, one can still using the generic pre-processing and phase retrieval capabilities of the Cohere framework on data that has been prepared outside of the framework for processing.

The workshop will finish with a deeper dive into the structure of cohere-core and cohere-beamlines to encourage wide-spread adoption of Cohere and development of new capabilities within the Cohere framework. 

Primary organizers: Steven Henke and Ming Du

This workshop will cover the fundamental optics and numerical optimization theories of x-ray ptychography, and offer the hands-on opportunity of running ptychographic data processing and reconstructions with tools intensively used at the Advanced Photon Source. These tools include Ptychodus, a user-friendly frontend and workflow manager integrating both traditional and AI-based reconstruction backends; we will also demonstrate Pty-Chi, one of the backends used by Ptychodus which offers reconstruction engines based on analytical methods, automatic differentiation, and deep image prior, through its Python API.

Primary organizers: Qingteng Zhang, Miaoqi Chu, and Samuel Marks

XPCS is a technique that evaluates real-space structural dynamics via the decorrelation of reciprocal-space coherent X-ray scattering intensities (i.e. "speckles"). A common challenge faced by XPCS users is determining exactly what physical quantities the technique measures, beyond standard intensity correlation functions (e.g., multitau g2 and two-time). The answer to this question usually forms the core of the resulting scientific interpretation. 

In this workshop, we will present a review of XPCS case studies where quantitative physical parameters, some of which can be cross-validated using theoretical models or small-scale simulations, can be extracted from g2 and two-time. These physical parameters cover a wide spectrum of materials science, ranging from microscopic return-point memory in magnetic domains to the interaction potentials of surface-engineered nanoparticles. These examples highlight the versatility of XPCS and its compatibility with sophisticated in situ and operando sample environments. Finally, we will introduce emerging data analysis frameworks, such as GPU-based real-time XPCS reduction and unsupervised deep learning designed to classify heterogeneous relaxation dynamics, which will accelerate the discovery of structure-property relationships in large-scale synchrotron datasets. We will conclude the session by answering questions from the audience regarding the applicability of XPCS to specific science questions from prospective users.

Primary organizer: Colin Ophus

Electron ptychography and other phase-contrast methods make it possible to accurately resolve light elements and low-contrast structures, even down to atomic resolution at low electron dose. This hands-on workshop introduces the core concepts behind phase-contrast reconstruction in STEM and then focuses on practical, end-to-end workflows in the open-source quantEM software package, from data setup and calibration through forward modeling, reconstruction, and quality checks.

Tutorials will cover introductory python, differential phase contrast (DPC), direct ptychography (including SSB and the parallax approximation), single-slice iterative ptychography, and 3D multislice ptychography. We will also perform mixed-state and inverse multislice reconstructions, and conclude with ptychography using deep generative priors to improve robustness. Most of the session will be interactive, using guided notebooks and experimental datasets; attendees are encouraged to bring a laptop to follow along and leave with reusable ptychography workflows.