Development and irradiation test of lost alpha detection system for ITER

Area of Science:

• Nuclear Fusion Science
• Plasma Physics
• Materials Science

Background:

• Burning plasma experiments require diagnostics for energetic particles like alpha particles.
• Understanding alpha particle loss is crucial for fusion reactor performance and safety.

Purpose of the Study:

• To develop a robust lost alpha particle detection system for high-temperature environments.
• To propose and test a novel diagnostic technique: alpha particle induced gamma ray spectroscopy.

Main Methods:

• Designed Ag:ZnS and Ce:YAG scintillators for high-temperature operation.
• Developed an optical transmission line for signal transfer.
• Irradiated optical components (lenses, mirrors) with a neutron flux of 9.6×10(17) nm⁻²s⁻¹ for 48 hours.
• Conducted laboratory tests using a Ce:Lu2SiO5 scintillator and an Am-Be source to detect 4.44 MeV gamma rays from the 9Be(α,nγ)12C reaction.

Main Results:

• Optical components showed no significant degradation after neutron irradiation.
• Successfully detected 4.44 MeV gamma rays, indicating the feasibility of the proposed spectroscopy method.

Conclusions:

• The developed detection system and diagnostic method are suitable for burning plasma experiments.
• Alpha particle induced gamma ray spectroscopy offers a viable approach for monitoring alpha particle loss in fusion devices.