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Assessing pseudo-automatic model analysis of small-angle scattering data batches from precipitation in alloys

Tidefelt, Mattias ; Jönsson, Per ; Olsson, Pär LU and Fisk, Martin LU (2026) In Computer Physics Communications 328.
Abstract
The ability to achieve controlled distributions of precipitates is one of the cornerstones of alloy optimization, in which small-angle scattering (SAS) serves as a powerful technique to characterize these distributions. One method of analyzing SAS data involves form factor intensity models, where modeled distribution parameters are obtained by solving a nonlinear least-squares (NLS) problem. However, the NLS method with a simultaneous search for all model parameters minimizes a very ill-conditioned objective function, which leads to a large number of search iterations and can give inadequate solutions. With the advancement of the 4th generation synchrotron rings and their potentially large datasets, it is increasingly important to find new... (More)
The ability to achieve controlled distributions of precipitates is one of the cornerstones of alloy optimization, in which small-angle scattering (SAS) serves as a powerful technique to characterize these distributions. One method of analyzing SAS data involves form factor intensity models, where modeled distribution parameters are obtained by solving a nonlinear least-squares (NLS) problem. However, the NLS method with a simultaneous search for all model parameters minimizes a very ill-conditioned objective function, which leads to a large number of search iterations and can give inadequate solutions. With the advancement of the 4th generation synchrotron rings and their potentially large datasets, it is increasingly important to find new and efficient numerical strategies for high throughput analysis. As a step in this direction, the purpose of this work is to investigate a pseudo-automatic numerical solution strategy based on the separable NLS method. The strategy is assessed in terms of correlation and precision of the model parameters, as well as convergence of the solution, using both synthetic and experimental scattering datasets. The decoupled fitting approach favors efficient parallelized batch fitting, which provides linear speedup for appropriate workloads. To support further development, the compounded features of the proposed solution strategy are packed into an easily accessible modular framework named python Small Angle Scattering Analysis (pySASA), which is openly available. (Less)
Abstract (Swedish)
The ability to achieve controlled distributions of precipitates is one of the cornerstones of alloy optimization, in which small-angle scattering (SAS) serves as a powerful technique to characterize these distributions. One method of analyzing SAS data involves form factor intensity models, where modeled distribution parameters are obtained by solving a nonlinear least-squares (NLS) problem. However, the NLS method with a simultaneous search for all model parameters minimizes a very ill-conditioned objective function, which leads to a large number of search iterations and can give inadequate solutions. With the advancement of the 4th generation synchrotron rings and their potentially large datasets, it is increasingly important to find new... (More)
The ability to achieve controlled distributions of precipitates is one of the cornerstones of alloy optimization, in which small-angle scattering (SAS) serves as a powerful technique to characterize these distributions. One method of analyzing SAS data involves form factor intensity models, where modeled distribution parameters are obtained by solving a nonlinear least-squares (NLS) problem. However, the NLS method with a simultaneous search for all model parameters minimizes a very ill-conditioned objective function, which leads to a large number of search iterations and can give inadequate solutions. With the advancement of the 4th generation synchrotron rings and their potentially large datasets, it is increasingly important to find new and efficient numerical strategies for high throughput analysis. As a step in this direction, the purpose of this work is to investigate a pseudo-automatic numerical solution strategy based on the separable NLS method. The strategy is assessed in terms of correlation and precision of the model parameters, as well as convergence of the solution, using both synthetic and experimental scattering datasets. The decoupled fitting approach favors efficient parallelized batch fitting, which provides linear speedup for appropriate workloads. To support further development, the compounded features of the proposed solution strategy are packed into an easily accessible modular framework named python Small Angle Scattering Analysis (pySASA), which is openly available. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Computer Physics Communications
volume
328
article number
110301
pages
13 pages
publisher
Elsevier
ISSN
0010-4655
DOI
10.1016/j.cpc.2026.110301
language
English
LU publication?
yes
id
d986e6b2-c016-4bb9-88b0-bbaf9824766c
date added to LUP
2026-07-17 10:46:14
date last changed
2026-08-26 14:11:36
@article{d986e6b2-c016-4bb9-88b0-bbaf9824766c,
  abstract     = {{The ability to achieve controlled distributions of precipitates is one of the cornerstones of alloy optimization, in which small-angle scattering (SAS) serves as a powerful technique to characterize these distributions. One method of analyzing SAS data involves form factor intensity models, where modeled distribution parameters are obtained by solving a nonlinear least-squares (NLS) problem. However, the NLS method with a simultaneous search for all model parameters minimizes a very ill-conditioned objective function, which leads to a large number of search iterations and can give inadequate solutions. With the advancement of the 4th generation synchrotron rings and their potentially large datasets, it is increasingly important to find new and efficient numerical strategies for high throughput analysis. As a step in this direction, the purpose of this work is to investigate a pseudo-automatic numerical solution strategy based on the separable NLS method. The strategy is assessed in terms of correlation and precision of the model parameters, as well as convergence of the solution, using both synthetic and experimental scattering datasets. The decoupled fitting approach favors efficient parallelized batch fitting, which provides linear speedup for appropriate workloads. To support further development, the compounded features of the proposed solution strategy are packed into an easily accessible modular framework named python Small Angle Scattering Analysis (pySASA), which is openly available.}},
  author       = {{Tidefelt, Mattias and Jönsson, Per and Olsson, Pär and Fisk, Martin}},
  issn         = {{0010-4655}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Computer Physics Communications}},
  title        = {{Assessing pseudo-automatic model analysis of small-angle scattering data batches from precipitation in alloys}},
  url          = {{https://lup.lub.lu.se/search/files/255718608/Tidefelt_2026.pdf}},
  doi          = {{10.1016/j.cpc.2026.110301}},
  volume       = {{328}},
  year         = {{2026}},
}