Solid debris collection for radiochemical diagnostics at the National Ignition Facility.

Area of Science:

• Nuclear Fusion Science
• Plasma Physics
• Radiochemistry

Background:

• Radiochemical analysis of post-ignition debris is crucial for diagnosing fusion capsule implosion efficiency at the National Ignition Facility (NIF).
• Current methods face limitations in distinguishing ablator material and efficiently collecting capsule debris post-implosion.

Purpose of the Study:

• To determine the chemical nature and distribution of debris within the NIF target chamber.
• To evaluate the capture efficiency of activated gold (Au) hohlraum debris on passive foils.
• To inform the design of an on-line debris collection system.

Main Methods:

• Radiochemical analysis of post-ignition debris samples.
• Deployment of passive foils (5 cm diameter) at 50 cm from target center for debris capture.
• Assessment of activated gold debris distribution.

Main Results:

• Preliminary data indicate that debris distribution within the target chamber is not uniform.
• Local heterogeneity in debris distribution was observed along equatorial and polar lines-of-sight.

Conclusions:

• Understanding debris characteristics is essential before developing an on-line collection system.
• Activated gold hohlraum debris exhibits heterogeneous distribution, impacting collection strategies.
• Further investigation into debris distribution is necessary for optimizing diagnostic and collection methods.