A new soft x-ray pulse height analysis array in the HL-2A tokamak

Area of Science:

• Plasma Physics
• Tokamak Fusion Research
• X-ray Spectroscopy

Background:

• Traditional soft x-ray pulse height analysis (PHA) systems face limitations in measurement accuracy and resolution.
• The HL-2A tokamak requires advanced diagnostic tools for precise plasma characterization.
• Silicon drift detectors (SDD) offer high performance for radiation detection.

Purpose of the Study:

• To develop and evaluate a new soft x-ray PHA array for the HL-2A tokamak.
• To improve measurement accuracy and spatiotemporal resolution of soft x-ray diagnostics.
• To enable the derivation of electron velocity distribution from soft x-ray spectra.

Main Methods:

• Development of a novel soft x-ray PHA array with nine independent subsystems.
• Integration of a nonconventional software multichannel analysis system.
• Utilisation of a linear array of nine high-performance silicon drift detectors (SDD).

Main Results:

• The new SDD-based PHA system significantly enhances measurement accuracy and spatiotemporal resolution.
• Achieved a high peak-to-background ratio (p/b ≥ 3000), allowing spectra approximation to electron velocity distribution.
• Successfully derived electron velocity distribution in pure ohmic and auxiliary heating discharges.

Conclusions:

• The developed soft x-ray PHA array represents a significant advancement in tokamak plasma diagnostics.
• SDD technology provides superior performance for soft x-ray spectral analysis.
• The system's capability to determine electron velocity distribution is vital for understanding plasma behavior.