First fusion proton measurements in TEXTOR plasmas using activation technique

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Particle Diagnostics

Background:

• Measuring MeV particle loss, especially alpha particles, in large fusion devices like ITER is challenging.
• Further research and development are crucial for ITER's operational success.

Purpose of the Study:

• To perform the first measurement of 3 MeV escaping fusion protons from TEXTOR tokamak plasmas.
• To demonstrate the feasibility and improvements of the activation technique for fusion proton detection.

Main Methods:

• Utilized an ion camera with a collimator and activation detectors inside the TEXTOR vacuum vessel.
• Analyzed irradiated detectors using ultra-low-level gamma-ray spectrometry at the HADES underground laboratory.
• Reduced detector cooling time by a factor of 50 compared to previous studies.

Main Results:

• Successfully detected 3 MeV escaping fusion protons from TEXTOR tokamak plasmas.
• Observed approximately 6 times more protons compared to earlier measurements on the JET tokamak.
• Enabled detection of radionuclides with half-lives as short as 90 minutes due to reduced cooling time.

Conclusions:

• The activation technique is a viable method for measuring escaping fusion protons in tokamaks.
• Significant improvements in detection sensitivity and reduced analysis time were achieved.
• This technique provides valuable data for understanding particle loss in fusion devices and is promising for ITER.