Interferometric microscope with a confocal focusing for inner surface defect detection of ICF capsule

Area of Science:

• Optics and Photonics
• Materials Science
• Fusion Energy Research

Background:

• Inner surface defects in inertial confinement fusion (ICF) capsules are critical to ignition failure.
• Current detection methods for these defects are often destructive or ineffective.
• There is a need for advanced non-destructive techniques to ensure ICF capsule integrity.

Purpose of the Study:

• To introduce the first non-destructive detection method for ICF capsule inner surface defects.
• To present a novel interferometric microscope with confocal focusing (CFIM) system.
• To address the challenge of accurately identifying and characterizing internal capsule flaws.

Main Methods:

• Utilizing confocal technology for precise axial positioning of the capsule and camera.
• Employing phase-shifting interferometry with a short-coherence source and spherical reference.
• Implementing in-situ focusing via camera axial adjustment to distinguish real from fake inner defects.

Main Results:

• CFIM successfully achieved precise imaging of the ICF capsule's inner surface.
• The system effectively identified inner surface defects by analyzing interferograms.
• Comparative experiments with scanning electron microscopy validated CFIM's feasibility and accuracy.
• CFIM resolved the issue of distinguishing fake inner defects caused by outer surface irregularities.

Conclusions:

• CFIM offers the first non-destructive approach for detecting inner surface defects in ICF capsules.
• The system's unique confocal and in-situ focusing capabilities enhance defect detection accuracy.
• This advancement is crucial for improving the reliability and success rate of ICF experiments.