1. Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device.
- Author
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Kawachi, Y., Ogawa, K., Osakabe, M., Kawamoto, Y., Isobe, M., and Ida, K.
- Subjects
CHARGE coupled devices ,FAST ions ,PHOTOMULTIPLIERS ,SIGNAL-to-noise ratio ,SAMPLING (Process) - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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