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Author: search.filters.author.Nilgumhang, Kewalee

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    Characterization of dust particles generated in Thailand Tokamak-1
    (2027-01-01)
    Nilgumhang, Kewalee
    ;
    Chokchaiworadilok, Sirat
    ;
    Poolyarat, Nopporn
    ;
    Dangtip, Somsak
    ;
    Limsuwan, Pichet
    Thailand Tokamak-1 (TT-1) is the first magnetic confinement fusion device in Thailand and the ASEAN region. During plasma operation, plasma–wall interactions (PWI) inevitably lead to erosion of the 316L stainless-steel vacuum vessel and the boronized first wall, resulting in dust generation and plasma contamination. This work investigates the morphology and elemental composition of dust particles collected from the TT-1 vacuum chamber after plasma campaigns. In this experiment, we carried out a total of 604 discharge operation shots over a period of three months, using 99.999% purity H<inf>2</inf> gas as the fuel gas and 99.999% purity He gas for Glow Discharge Cleaning (GDC). Dust was sampled from the inner surface of the vacuum vessel using carbon tape and analyzed by field-emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Four primary dust morphologies were identified: (i) smooth flake-like particles, (ii) grain-crack particles with surface cracking, (iii) granular particles with fine grains distributed across the surface, and (iv) cauliflower-like structures attributed to repeated thermal cycling. EDS analysis revealed that Fe, Cr, and Ni, originating from the 316L stainless-steel wall, are the dominant metallic constituents, together with light elements such as B, C, and O associated with the boronization layer and subsequent oxidation. The presence of B- and C-rich granular dust confirms successful deposition and erosion of the boron coating used for wall conditioning. These results demonstrate that dust generated in TT-1 is a mixture of wall and boronization-layer fragments, which poses potential theoretical risks of plasma impurity accumulation, enhanced radiative losses, and compromised plasma ignition and stability in future high-performance campaigns. The present characterization provides a basis for future studies on dust transport, retention, and mitigation strategies in TT-1 and similar medium-size tokamak devices.
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    OSL chronology of stratified iron-smelting slag from the Don up Mung site, northeastern Thailand
    (2026-11-01)
    Phetkongtong, Thananan
    ;
    Nilgumhang, Kewalee
    ;
    Wongadsapaiboon, Thippawan
    ;
    Pailoplee, Santi
    ;
    Limsuwan, Pichet
    Iron-smelting slag from the Don Up Mung archaeological site, Nong Bua Lamphu Province, northeastern Thailand, was investigated to evaluate the applicability of Optically Stimulated Luminescence (OSL) dating for archaeometallurgical materials. Slag samples recovered from stratified deposits between the surface and 100–110 cm depth were dated using the quartz inclusion method with the Single Aliquot Regeneration (SAR) protocol. Environmental dose rates were quantified by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) through in situ determination of uranium (U), thorium (Th), and potassium (K) concentrations, minimizing spatial heterogeneity effects commonly associated with bulk measurements. The obtained OSL ages range from 1426 ± 162 year to 2539 ± 223 year, indicating consistent burial histories across stratigraphic levels. Independent Accelerator Mass Spectrometry (AMS) radiocarbon ages of charcoal and human bone (1700–2600 year) show good agreement with the OSL results, supporting the reliability of the luminescence-derived chronology. These results demonstrate that OSL dating of iron-smelting slag, when combined with high-resolution dose rate assessment, provides robust chronological constraints and represents a valuable radiation-based approach for reconstructing metallurgical activity sequences in Southeast Asia.