Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device

Y Kawachi; K Ogawa; M Osakabe; Y Kawamoto; M Isobe; K Ida

doi:10.1063/5.0159175

Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device

Rev Sci Instrum. 2023 Oct 1;94(10):103505. doi: 10.1063/5.0159175.

Authors

Y Kawachi¹, K Ogawa^{2

3}, M Osakabe^{2

3}, Y Kawamoto^{2

3}, M Isobe^{2

3}, K Ida^{2

3}

Affiliations

¹ Department of Electronics, Kyoto Institute of Technology, Matsugasaki, Sakyo Ward, Kyoto 606-8585, Japan.
² National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan.
³ The Graduate University for Advanced Studies, SOKENDAI, Toki, Japan.

PMID: 37819204
DOI: 10.1063/5.0159175

Abstract

A fast-sampling fast-ion D-alpha (F-FIDA) measurement has been developed in the large helical device in order to investigate fast ion dynamics associated with helically trapped fast-ion-driven Magnetohydrodynamic (MHD) bursts. F-FIDA consists of a multi-anode photomultiplier tube (PMT) and achieves a sampling rate of 10 kHz. During the deuterium experiment campaign in 2022, F-FIDA measured the spectrum of perpendicular fast ions, using perpendicular lines of sight. We compared F-FIDA with conventional FIDA, using an electron multiplying charge coupled device, and confirmed that the time-averaged images were generally consistent between the two. The statistical properties of the temporal evolution associated with MHD bursts were analyzed using a conditional sampling technique. The results showed that the PMT signal varied in different spatial and wavelength channels. Although the signal-to-noise ratio was poor and there was room for improvement, it could provide useful information for studies on the phase-space dynamics of fast ions.