The multi-spectral imaging diagnostic

Area of Science:

• Plasma physics
• Optical diagnostics
• Spectroscopy

Background:

• Advanced diagnostics are crucial for understanding fusion plasmas.
• Existing imaging systems face limitations in throughput and spectral resolution.
• Multi-spectral imaging offers potential for simultaneous multi-wavelength measurements.

Purpose of the Study:

• To introduce and validate a novel Multi-Spectral Imaging (MSI) system for plasma diagnostics.
• To demonstrate the capability of MSI for 2D mapping of atomic line intensities and ratios.
• To assess the performance of the MSI system in terms of resolution, calibration, and throughput.

Main Methods:

• A modified polychromator design enables sequential filtering and focusing of images.
• Commercial CMOS cameras are utilized for image acquisition.
• Absolute calibration is performed using an integrating sphere and cross-referencing with CAD models.
• The system was tested on Alcator C-Mod and TCV tokamak devices.

Main Results:

• The MSI system successfully captured simultaneous spectrally filtered images.
• 2D mappings of atomic line ratios and absolute intensities were achieved with high spatial registration.
• Minimal vignetting and aberrations were observed.
• The system demonstrated high throughput and accurate spectral transmission calibration.

Conclusions:

• The developed Multi-Spectral Imaging system is a viable and effective diagnostic tool for fusion research.
• MSI enables advanced plasma characterization through simultaneous multi-wavelength imaging.
• The system's calibration and registration capabilities allow for quantitative analysis of plasma properties.