Pixel-to-pixel variation on a calibrated PILATUS3-based multi-energy soft x-ray detector

Area of Science:

• Plasma Physics
• Fusion Energy Research
• X-ray Detection Technology

Background:

• The Madison Symmetric Torus (MST) requires advanced diagnostics for plasma characterization.
• Existing x-ray diagnostics may lack the necessary spatial and spectral resolution for detailed plasma property inference.

Purpose of the Study:

• To introduce and calibrate a novel multi-energy soft x-ray pin-hole camera system.
• To assess the system's capability for measuring plasma x-ray emissivity with high resolution.
• To demonstrate the inference of crucial plasma parameters like electron temperature (Te) and effective charge (Zeff).

Main Methods:

• Installation of a PILATUS3 100 K x-ray detector on the MST.
• Utilizing the detector's pixel-specific energy threshold capabilities for multi-energy measurements.
• Calibration of energy dependence across different ranges (1.6-6 keV and 4-14 keV) using fluorescence targets and trimbit settings.
• Fitting calibration data to an 'S-curve' model to map trimbit settings to energy thresholds.

Main Results:

• Successful calibration of the detector for the 1.6-6 keV range with an effective threshold resolution of ΔE < 100 eV.
• Calibration for the 4-14 keV range achieved with a resolution of ΔE < 200 eV.
• Demonstrated potential for unique spatial and spectral resolution in plasma x-ray emissivity measurements.

Conclusions:

• The new multi-energy soft x-ray camera system provides high-resolution diagnostics for the MST.
• The system enables accurate inference of essential plasma properties (Te, nZ, Zeff).
• This technology advances the capabilities for understanding and controlling fusion plasmas.