Machine Learning: Science and Technology (Jan 2024)

Learning continuous scattering length density profiles from neutron reflectivities using convolutional neural networks

  • Brian Qu,
  • Panagiotis Christakopoulos,
  • Hanyu Wang,
  • Jong Keum,
  • Polyxeni P Angelopoulou,
  • Peter V Bonnesen,
  • Kunlun Hong,
  • Mathieu Doucet,
  • James F Browning,
  • Miguel Fuentes-Cabrera,
  • Rajeev Kumar

DOI
https://doi.org/10.1088/2632-2153/ad9809
Journal volume & issue
Vol. 5, no. 4
p. 045065

Abstract

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Interpreting neutron reflectivity (NR) data using ad hoc multi-layer models and physics-based models provides information about spatially resolved neutron scattering length density (NSLD) profiles. Recent improvements in data acquisition systems have allowed acquiring thousands of NR curves in a couple of hours, which has led to a need for automated data analysis tools to interpret NR measurements in real-time. Here, we present a machine learning analysis workflow that uses a series of models, based on a convolutional neural network (CNN), to learn the relation between the NSLDs and the NRs, and subsequently produce continuous NSLD profiles directly from NRs. The usefulness of our CNN-based models is demonstrated by constructing NSLDs from NRs of several films containing homopolymer polyzwitterions and diblock copolymers mixed with different types of salts. Comparisons of the NSLDs with those constructed using ad hoc multi-layer models reveal a very good agreement, suggesting the potential of CNN-based models for real-time automated data analysis of NRs.

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