Introduction
NEREIDS (Neutron rEsonance REsolved Imaging Data Analysis System) is a Rust-based library for neutron resonance imaging at the VENUS beamline, Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL).
What It Does
NEREIDS provides end-to-end analysis for time-of-flight (TOF) neutron resonance imaging: input hyperspectral TOF data, output spatially resolved isotopic and elemental composition maps.
The analysis pipeline:
- Load raw TOF imaging data (TIFF stacks, NeXus/HDF5, or pre-normalized transmission)
- Normalize sample and open-beam measurements to transmission
- Configure isotopes of interest using ENDF nuclear data
- Fit resonance models to measured transmission spectra
- Map fitted parameters (areal density, temperature) across each pixel
Interfaces
NEREIDS ships in several interfaces:
| Deliverable | Use case |
|---|---|
Rust library (nereids-* crates) | Embed in Rust applications, maximum performance |
Python bindings (pip install nereids) | Jupyter notebooks, scripting, integration with NumPy/SciPy |
Desktop GUI (nereids-gui) | Interactive analysis with visual feedback |
MCP server (nereids-mcp) | Local AI-agent assisted analysis through manifest-driven workflows |
Relationship to SAMMY
NEREIDS implements the same physics as SAMMY (a Fortran code for multilevel R-matrix analysis of neutron data, ORNL/TM-9179/R8), rewritten in Rust with modern tooling. All physics modules reference specific SAMMY source files and equation numbers in their documentation.
Key formalisms from SAMMY:
- Reich-Moore R-matrix (LRF=3)
- Breit-Wigner, single- and multi-level (LRF=1/2)
- R-Matrix Limited (LRF=7)
- Free Gas Model Doppler broadening
- Gaussian + exponential resolution broadening
- Unresolved Resonance Region (LRU=2)
Next Steps
- Install NEREIDS for your platform
- Try the Rust quickstart or Python quickstart
- Explore the GUI walkthrough for interactive analysis