SAILS: Spectral Adjustment through Iterative Least Squares

The Challenge

Neutron spectrum adjustment is a complex and computationally intensive process, particularly when using experimental reaction rates from IRDFF materials. The large number of neutron energy groups compared to the limited number of experimental wires (<10) makes spectral unfolding a difficult mathematical challenge. Existing software, such as the STAYSL PNNL package, is NQA-1 qualified but has limitations when applied to the Transient Reactor Test (TREAT) facility, a graphite-moderated transient reactor at Idaho National Laboratory. Researchers need a more adaptable and iterative approach to spectrum deconvolution that improves accuracy and usability.

How It Works

Spectral Adjustment through Iterative Least Squares (SAILS) enhances neutron spectrum unfolding by iterating solutions after each least-squares minimization step, rather than relying on a single-pass adjustment. Built on the STAYSL framework, SAILS reduces the complexity of data manipulation while improving accuracy in neutron spectrum deconvolution.

• Iterative Refinement: Instead of relying on a single least-squares operation, SAILS iterates the solution after each adjustment step.

• Enhanced Accuracy for TREAT Reactor Data: Provides a better fit for neutron spectra in graphite-moderated transient reactors, where traditional STAYSL methods struggle.

• Simplified User Interface: Eliminates the need for complex manual data adjustments, making spectral unfolding more accessible to neutron experimenters.

• Maintains NQA-1 Standards: Retains the rigor and reliability of STAYSL PNNL while introducing improvements in iterative computation.

Key Advantages

• More Accurate Spectral Unfolding: Iterative adjustments improve neutron spectrum accuracy over traditional single-pass methods.

• Better Performance at TREAT Facility: Addresses STAYSL's limitations when applied to graphite-moderated reactors.

• User-Friendly Interface: Reduces manual data manipulations, streamlining spectral adjustment workflows.

• Retains Industry Standards: Built on STAYSL’s foundation, ensuring continuity with existing methodologies.

• Optimized for Neutron Experimentation: Tailored for scientists and researchers conducting neutron spectrum analysis.

Market Applications

• Neutron Experimenters – Improve spectral unfolding accuracy with an iterative least-squares approach.

• Nuclear Research Facilities – Apply to experiments in transient reactors and graphite-moderated systems.

• Radiation Dosimetry & Shielding Studies – Enhance reaction rate-based neutron spectrum analysis.

• Scientific Computing & Nuclear Data Analysis – Optimize mathematical models for neutron energy spectrum calculations.

This software is a controlled nuclear code, subject to a special release process due to its sensitive nature. Please visit the Nuclear Computational Resource Center and create an account to request access.