Development of neutron activation system on EAST

Area of Science:

• Nuclear Fusion Diagnostics
• Plasma Physics
• Neutron Activation Analysis

Background:

• Accurate measurement of neutron yield is crucial for understanding fusion reactions in tokamaks.
• Existing diagnostics may have limitations in precision, dynamic range, or specific applications.
• The Experimental Advanced Superconducting Tokamak (EAST) requires reliable neutron diagnostics for its experiments.

Purpose of the Study:

• To develop and validate a robust neutron activation system (NAS) for time-integrated neutron yield measurement on the EAST tokamak.
• To investigate the performance of high-purity materials as neutron detectors within the NAS.
• To establish a precise and wide dynamic range diagnostic for fusion neutron analysis.

Main Methods:

• Utilized a pneumatic transfer system to deliver neutron detector samples (Indium, Silicon) to the EAST device.
• Employed a high-purity germanium spectrometer to measure decay gamma rays from activated samples.
• Calibrated detection efficiencies at 336 keV (6.9%) and 1779 keV (1.7%).
• Compared NAS neutron flux measurements with fission chamber counts during neutral beam injection experiments.

Main Results:

• Successfully implemented Indium (0.3 MeV threshold) and Silicon (4.0 MeV threshold) samples for DD and DT neutron yield diagnosis.
• Demonstrated a wide dynamic range for DD neutron yield measurement, from 1.9 × 10^12 to 5.9 × 10^14 n/shot.
• Validated the NAS performance through comparison with established fission chamber diagnostics.

Conclusions:

• The developed neutron activation system (NAS) is a robust and high-precision diagnostic for time-integrated neutron yield on EAST.
• The NAS, utilizing Indium and Silicon detectors, effectively measures DD and DT neutron yields in fusion experiments.
• This diagnostic provides reliable data crucial for advancing fusion energy research on EAST.