Asia Pacific Physics Week 2024 (APPW2024)

Monday, Nov. 4, 2024

3:40 PM - 4:20 PM  Plenary Talk: Siriyaporn Sangaroon (Mahasarakham University) 

D-D neutron spectroscopy in magnetic confinement fusion: insights from compact neutron emission spectrometers

Siriyaporn Sangaroon*, Kunihiro Ogawa **,***, and Mitsutaka Isobe**,***

* Mahasarakham University, Kantarawichai District, Maha Sarakham, 44150, Thailand

** National Institute for Fusion Science, National Institutes of Natural Sciences, Oroshi-cho, Toki, 509-5292, Japan

*** The Graduate University for Advanced Studies, SOKENDAI, Oroshi-cho, Toki, 509-5292, Japan

In magnetic confinement fusion, plasmas are primarily heated by auxiliary systems, such as neutral beam injection, which serves as the main source of fast ions. Understanding fast-ion transport is essential for achieving high-performance plasmas. Fast ions in fusion plasmas leave distinct signatures in neutron emissions, making neutron spectroscopy of deuterium-deuterium (D-D) plasmas a valuable tool for studying fast-ion behavior. One of the most powerful instruments for neutron spectroscopy is the compact neutron emission spectrometer (CNES). CNES, utilizing conventional liquid (EJ-301) scintillation detectors and the newly developed Cs2LiYCl scintillation detector with 7Li enrichment (CLYC7), was deployed along both tangential and perpendicular sightlines in the Large Helical Device (LHD). Significant Doppler shifts in neutron energy spectra, attributable to fast-ion velocities, were successfully observed. Furthermore, the expected D-D neutron energy spectrum from CNES measurements was calculated using the five-dimensional orbit-following code DELTA5D, which accounts for Larmor motion effects. The strong agreement between experimental results and theoretical calculations underscores the effectiveness of CNES in fast-ion diagnostics.