Effect of high-energy neutral particles on extreme ultraviolet spectroscopy in large helical device

Journal Article · Mon Oct 15 00:00:00 EDT 2012 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4733733· OSTI ID:22093821

Chunfeng, Dong; Sakaue, Hiroyuki ^[1]; Morita, Shigeru; Tokitani, Masayuki; Goto, Motoshi ^[1]; Wang, Erhui ^[2]; Zushi, Hideki ^[3]

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1. National Institute for Fusion Science, Toki 509-5292, Gifu (Japan)
2. Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan)
3. RIAM, Kyushu University, Kasuga 816-8580, Fukuoka (Japan)

Spectra measured by an extreme ultraviolet (EUV) spectrometer frequently suffer large spike noise when Large Helical Device is operated in low-density range ({<=}3 Multiplication-Sign 10{sup 13} cm{sup -3}) with neutral beam injection (NBI). The spike noise completely disappears in electron cyclotron heating discharges. In order to examine the effect of NBI, a carbon filter with thickness of 150 nm was installed in the EUV spectrometer. As a result, the spike noise was reduced by an order of magnitude. It is experimentally verified that the spike noise is caused by escaping high-energy neutral particles resulting from the circulating high-energy hydrogen ions borne from NBI.

• OSTI ID: 22093821
• Journal Information: Review of Scientific Instruments, Vol. 83, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ECR HEATING
EXTREME ULTRAVIOLET RADIATION
LHD DEVICE
NEUTRAL PARTICLES
PLASMA BEAM INJECTION
SPECTRA
SPECTROMETERS
SPECTROSCOPY
THICKNESS