Speaker
Description
The Spallation Neutron Source at the Oak Ridge National Laboratory is driven by a linear accelerator that is currently undergoing an upgrade to 2.8 MW proton beam power with 1.3 GeV proton energy. Besides powering the First Target Station, which is in operation since 2006, the accelerator will provide 700 kW of proton beam power to the Second Target Station (STS), which is currently in the preliminary design phase. The STS will accommodate 18 to 20 neutron scattering instruments, the first three of which are expected to deliver early science in 2034.
The STS is being designed to become the world’s highest peak brightness source of cold neutrons. To facilitate the design process of the STS target and moderators, we have developed a fully automated optimization workflow that enables efficient, high-fidelity modeling, simulation, and optimization of new designs. In this workflow, a parametrized solid geometry from SolidWorks and SpaceClaim is converted into unstructured mesh geometry with Attila4MC, a neutronics calculation is run with MCNP6.2, followed optionally by a mechanical analysis in Sierra. The optimization is managed by Dakota.
Previously, a detailed optimization of the moderator dimensions was performed while keeping the target and beam profile fixed. Additionally, the target and beam profile were optimized for a given moderator size. In this analysis, the optimization of the beam profile and the dimensions of the target and moderators are combined in a single analysis in which the peak and time-integrated brightness is maximized. We discuss the results of a detailed optimization of the two moderators with a fixed beam footprint. Afterwards, we discuss the effect of changing the beam footprint as well as the beam shape.
The presented optimization workflow can be used in the design of other high-power targets, neutron scattering facilities, nuclear or particle physics facilities, and radiotherapy systems.
