Speaker
Description
This contribution reports on the installation of a 100 µm testing neutron collimator for transmission measurements on the Device for Indirect Capture Experiments on Radionuclides (DICER) at the Los Alamos Neutron Science Center (LANSCE). The move toward smaller collimation is driven by radiological risk management: for experiments involving highly activatable or radioactive materials, reducing the beam spot and required sample mass can significantly reduce sample activation and associated dose consequences, enabling mission-driven measurements while minimizing operational hazard.
Achieving reliable performance with a 100 µm aperture requires both precise beamline alignment and an accurate “as-built” representation of the installed hardware. We therefore developed a metrology-to-simulation workflow that combines high-resolution 3D scanning with laser tracker surveys to capture the true collimator geometry and its alignment within the beamline reference frame. The resulting metrology data were merged and registered into an MCNP model so that simulations reflect the actual installed configuration rather than nominal CAD. In parallel, facility-wide 3D scanning was used to better constrain the position and orientation of the Mark IV spallation target, improving source-to-sample geometry and enabling higher-fidelity predictions of the beam spot at the sample location for benchmarking against beam measurements.
The workflow was exercised during a commissioning campaign in December 2025, and a follow-on measurement campaign with an Y-88 sample is planned for fall 2026, incorporating lessons learned from the initial tests. Overall, this work demonstrates how integrated high-precision metrology, modern 3D geometry handling, and STL-based workflows can strengthen alignment confidence and improve MCNP realism for small-aperture collimation in a large legacy neutron facility.