ICE-MAN, the Integrated Computational Environment-Modeling & Analysis for Neutrons at ORNL

by Dr Anibal Ramirez-Cuesta (Neutron Science Directorate, Oak Ridge National Laboratory)

Monday 3 Jun 2024, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

ICE-MAN is a modeling and analysis workbench for multi-modal studies, designed with neutron science in mind. The integrated and extensible environment provides scientists with a common interface to a suite of tools, and developers with a common API to seamlessly add new functionality. This project aims to reduce the barrier to analyze and interpret neutron scattering experiments in combination with other multi-technique research studies. It streamlines the workflow between different experimental techniques, computer modeling, and databases and reduces the time and learning curve needed to access them thus making a holistic approach to data interpretation more amenable and efficient.

1) ICE-MAN overcomes the limitation of an individual’s expertise to utilize different atomistic modeling techniques and to quickly compare simulated and experimental data.
2) At ORNL, ICE-MAN provides tools that can be used in 10 instruments.
3) ICEMAN can be used as: a) virtual machine in VirtualBox, b) Docker containers and c) as a web application in CADES [1]; in this form it is available to any user with an ORNL account.

At present, it has two main modules, OClimax [2] and QClimax [3]. Also there are several small modules to generate input files, read output files and convert formats. OClimax can model phonon and vibrational spectra for comparison with inelastic neutron scattering instruments and can be used to rigorously model both polycrystalline and single crystal spectra, including resolution considerations. Currently, OClimax is principally used on VISION (BL-16B) but can also be used to analyze phonon data from ARCS, CNCS, HySPEC, SEQUOIA, triple axes spectrometers (ORNL), LET, MAPS, MERLIN, TOSCA, (ISIS), DCS (NIST), etc. A necessary step in analyzing data with OClimax is performing DFT calculations. The ICEMAN project also aims to simplify this step in the analysis procedure, allowing for fast setup of initial files and running scripts for different DFT packages. The focused resources applied to data analysis on VISION (BL-16B) have contributed to it being the world leader in neutron vibrational spectroscopy measurements. The scientific output of the spectrometer is roughly 80% dependent on these analysis capabilities and has significantly improved the scientific impact of the instrument. QClimax, on the other hand, provides users with a flexible, straightforward environment to enable fitting to complex user-defined functions. It allows fits to be performed to data from multiple Q values simultaneously and provides global fitting parameters. QClimax can be used to analyze QENS data from any quasielastic spectrometer, including BASIS, CNCS (ORNL), DCS, HFBS (NIST), IRIS, OSIRIS (ISIS), TOFTOF (FRM II), etc. The ICEMAN project is still under active development, and the QENS analysis capabilities of QClimax are being refined with feedback from instrument staff and users.

[1] https://iceman.ornl.gov/ui/ICEMAN
[2] Y.Q. Cheng, L.L. Daemen, A.I. Kolesnikov, A.J. Ramirez-Cuesta A.J., Journal of Chemical Theory and Computation, 15, 1974-1982 (2019)
[3] E. Mamontov, R.W. Smith, J.J. Billings, A.J. Ramirez-Cuesta, Physica B: Condensed Matter, 566, 50-54 (2019).