Condensed Exponential Correlation Functions in Multicomponent Polymer Blends Measured by X-ray Photon Correlation Spectroscopy

2006 ◽  
Vol 39 (25) ◽  
pp. 8822-8831 ◽  
Author(s):  
Megan L. Ruegg ◽  
Amish J. Patel ◽  
Suresh Narayanan ◽  
Alec R. Sandy ◽  
Simon G. J. Mochrie ◽  
...  
Keyword(s):  
Polymer Blends ◽  
Correlation Functions ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
X Ray ◽  
Multicomponent Polymer

scholarly journals On the use of two-time correlation functions for X-ray photon correlation spectroscopy data analysis

2017 ◽  
Vol 50 (2) ◽  
pp. 357-368 ◽  
Author(s):  
Oier Bikondoa
Keyword(s):  
Correlation Functions ◽  
Photon Correlation Spectroscopy ◽  
Time Correlation ◽  
Correlation Spectroscopy ◽  
Time Correlation Functions ◽  
Spectroscopy Data ◽  
Photon Correlation ◽  
X Ray ◽  
Equilibrium Processes ◽  
Time Correlations

Multi-time correlation functions are especially well suited to study non-equilibrium processes. In particular, two-time correlation functions are widely used in X-ray photon correlation experiments on systems out of equilibrium. One-time correlations are often extracted from two-time correlation functions at different sample ages. However, this way of analysing two-time correlation functions is not unique. Here, two methods to analyse two-time correlation functions are scrutinized, and three illustrative examples are used to discuss the implications for the evaluation of the correlation times and functional shape of the correlations.

scholarly journals Noise reduction in X-ray photon correlation spectroscopy with convolutional neural networks encoder–decoder models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tatiana Konstantinova ◽  
Lutz Wiegart ◽  
Maksim Rakitin ◽  
Anthony M. DeGennaro ◽  
Andi M. Barbour
Keyword(s):  
Experimental Data ◽  
Correlation Functions ◽  
Photon Correlation Spectroscopy ◽  
Noise Removal ◽  
Time Correlation ◽  
Correlation Spectroscopy ◽  
Time Correlation Functions ◽  
Signal To Noise ◽  
Photon Correlation ◽  
X Ray

AbstractLike other experimental techniques, X-ray photon correlation spectroscopy is subject to various kinds of noise. Random and correlated fluctuations and heterogeneities can be present in a two-time correlation function and obscure the information about the intrinsic dynamics of a sample. Simultaneously addressing the disparate origins of noise in the experimental data is challenging. We propose a computational approach for improving the signal-to-noise ratio in two-time correlation functions that is based on convolutional neural network encoder–decoder (CNN-ED) models. Such models extract features from an image via convolutional layers, project them to a low dimensional space and then reconstruct a clean image from this reduced representation via transposed convolutional layers. Not only are ED models a general tool for random noise removal, but their application to low signal-to-noise data can enhance the data’s quantitative usage since they are able to learn the functional form of the signal. We demonstrate that the CNN-ED models trained on real-world experimental data help to effectively extract equilibrium dynamics’ parameters from two-time correlation functions, containing statistical noise and dynamic heterogeneities. Strategies for optimizing the models’ performance and their applicability limits are discussed.

scholarly journals From Femtoseconds to Hours–Measuring Dynamics over 18 Orders of Magnitude with Coherent X-rays

2021 ◽  
Vol 11 (13) ◽  
pp. 6179
Author(s):  
Felix Lehmkühler ◽  
Wojciech Roseker ◽  
Gerhard Grübel
Keyword(s):  
Time Scales ◽  
Free Electron Laser ◽  
Photon Correlation Spectroscopy ◽  
Signal To Noise Ratio ◽  
Coherent Scattering ◽  
Correlation Spectroscopy ◽  
X Rays ◽  
Photon Correlation ◽  
X Ray ◽  
Scattering Technique

X-ray photon correlation spectroscopy (XPCS) enables the study of sample dynamics between micrometer and atomic length scales. As a coherent scattering technique, it benefits from the increased brilliance of the next-generation synchrotron radiation and Free-Electron Laser (FEL) sources. In this article, we will introduce the XPCS concepts and review the latest developments of XPCS with special attention on the extension of accessible time scales to sub-μs and the application of XPCS at FELs. Furthermore, we will discuss future opportunities of XPCS and the related technique X-ray speckle visibility spectroscopy (XSVS) at new X-ray sources. Due to its particular signal-to-noise ratio, the time scales accessible by XPCS scale with the square of the coherent flux, allowing to dramatically extend its applications. This will soon enable studies over more than 18 orders of magnitude in time by XPCS and XSVS.

scholarly journals Grain Growth and Coarsening Dynamics in a Compositionally Asymmetric Block Copolymer Revealed by X-ray Photon Correlation Spectroscopy

2020 ◽  
Vol 53 (19) ◽  
pp. 8233-8243
Author(s):  
Ronald M. Lewis ◽  
Grayson L. Jackson ◽  
Michael J. Maher ◽  
Kyungtae Kim ◽  
Suresh Narayanan ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Grain Growth ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
X Ray ◽  
Coarsening Dynamics

scholarly journals Atomic Migration Studies with X-Ray Photon Correlation Spectroscopy

2014 ◽  
Vol 2 ◽  
pp. 73-94 ◽  
Author(s):  
Markus Stana ◽  
Manuel Ross ◽  
Bogdan Sepiol
Keyword(s):  
Low Temperatures ◽  
Short Range ◽  
Short Range Order ◽  
Photon Correlation Spectroscopy ◽  
Condensed Matter ◽  
Correlation Spectroscopy ◽  
Atomic Scale ◽  
Photon Correlation ◽  
X Ray ◽  
Amorphous Systems

The new technique of atomic-scale X-ray Photon Correlation Spectroscopy (aXPCS) makesuse of a coherent X-ray beam to study the dynamics of various processes in condensed matter systems.Particularly atomistic migration mechanisms are still far from being understood in most of intermetallicalloys and in amorphous systems. Special emphasis must be given to the opportunity to measureatomistic diffusion at relatively low temperatures where such measurements were far out of reach withpreviously established methods. The importance of short-range order is demonstrated on the basis ofMonte Carlo simulations.

scholarly journals Distributed X-ray photon correlation spectroscopy data reduction using Hadoop MapReduce

2018 ◽  
Vol 25 (4) ◽  
pp. 1135-1143 ◽  
Author(s):  
Faisal Khan ◽  
Suresh Narayanan ◽  
Roger Sersted ◽  
Nicholas Schwarz ◽  
Alec Sandy
Keyword(s):  
Real Time ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Frame Rate ◽  
Computational Techniques ◽  
Complex Materials ◽  
Photon Correlation ◽  
X Ray ◽  
Wide Range ◽  
Recent Developments

Multi-speckle X-ray photon correlation spectroscopy (XPCS) is a powerful technique for characterizing the dynamic nature of complex materials over a range of time scales. XPCS has been successfully applied to study a wide range of systems. Recent developments in higher-frame-rate detectors, while aiding in the study of faster dynamical processes, creates large amounts of data that require parallel computational techniques to process in near real-time. Here, an implementation of the multi-tau and two-time autocorrelation algorithms using the Hadoop MapReduce framework for distributed computing is presented. The system scales well with regard to the increase in the data size, and has been serving the users of beamline 8-ID-I at the Advanced Photon Source for near real-time autocorrelations for the past five years.

scholarly journals Demonstration of 3D Photon Correlation Spectroscopy in the hard X-ray regime

2021 ◽  
Author(s):  
Wonhyuk Jo ◽  
Rustam Rysov ◽  
FABIAN WESTERMEIER ◽  
Michael Walther ◽  
Leonard Mueller ◽  
...  
Keyword(s):  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
X Ray
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