Distribution of collected target debris using the large area solid debris radiochemistry collector

Area of Science:

• Nuclear Chemistry
• Radiochemistry
• Nuclear Physics

Background:

• The National Ignition Facility (NIF) enables studies of nuclear reactions and fission product behavior.
• Understanding fission product distribution is crucial for nuclear data applications and experimental design.

Purpose of the Study:

• To deploy and evaluate a large-area solid radiochemistry collector for capturing post-shot target debris at NIF.
• To analyze the spatial distribution of fission and activation products from uranium-238 under NIF conditions.
• To inform the design of future nuclear data experiments utilizing NIF capabilities.

Main Methods:

• Deployment of a 20-cm diameter vanadium foil collector with an aluminum side-enclosure, positioned 50 cm from the NIF target.
• Collection of debris from two NIF shots involving a uranium-238 monolayer within the target capsule.
• Gamma spectroscopy analysis of collected fission and activation products to determine their distribution.

Main Results:

• The collector achieved approximately 1% collection efficiency over the total 4π solid angle for solid target debris.
• Fission product distribution was non-uniform: peak and valley fission products preferentially collected on vanadium, while low- and high-mass products concentrated on the aluminum.
• Demonstrated the capability to collect and analyze fission products from NIF experiments.

Conclusions:

• The study successfully demonstrated the utility of a solid radiochemistry collector for NIF experiments.
• Observed non-uniform fission product deposition provides valuable insights into debris transport dynamics.
• Results will guide the optimization of collector design and experimental parameters for future nuclear data acquisition at NIF.