Rapid calibration plan for NIF's Near Backscatter Imager (NBI)

Area of Science:

• Plasma Physics
• Optical Diagnostics
• Fusion Energy Research

Background:

• The Near Backscatter Imager (NBI) at the National Ignition Facility (NIF) measures stimulated Brillouin and Raman backscatter.
• NBI works with the Full Aperture Backscatter System (FABS) for comprehensive backscatter characterization.
• NBI's Spectralon plate degrades due to exposure to high energy backscatter, neutrons, and debris, necessitating regular calibration.

Purpose of the Study:

• To develop and describe a rapid in situ calibration system for the NBI diagnostic.
• To ensure the continued accuracy of NBI measurements for Hohlraum laser coupling and laser-plasma interaction models.

Main Methods:

• Design and implementation of a novel rapid calibration system for NBI.
• Installation of the system inside the NIF target chamber for in situ measurements.

Main Results:

• The developed system is designed for rapid calibration of the NBI diagnostic.
• The system is scheduled for installation in FY25.

Conclusions:

• A new rapid calibration system will maintain the accuracy of NBI measurements.
• Accurate backscatter data is vital for refining laser-plasma interaction models at NIF.