Presentation Information
[3F09]Experimental study on vacuum characteristics and vapor behavior evaluation in A-FNS HEBT
*Takashi Ebisawa1, Sato Satoshi1, Makoto Oyaizu1, Noriyosu Hayashizaki1,2, Shota Ikeda2 (1. National Institutes for Quantum Science and Technology, 2. Science Tokyo)
The A-FNS project is ongoing for the fusion material study. The widely different vacuum pressure must be kept between the accelerator system (<10-5 Pa) to keep the availability, and the target system (>10-3 Pa) to prevent the Li boiling in A-FNS. Also, the contamination and vacuum degradation by liquid Li are concerned. Therefore, the experimental validation and Li vapor behavior are required for the operational parameters of Li target. For this study, we designed the dedicated experimental setup of differential vacuum pumping system with vacuum instruments. As a result, although the reaching pressure is higher than the design value, a stable Li flow was demonstrated under differential pumping from 10-2 Pa to 10-4 Pa. In addition, the vacuum condition of the accelerator vacuum was kept regardless of the operational parameter of Li target. In order to minimize the Li vapor contamination, we can conclude that the Li temperature and flow speed should be kept under 250 ℃ and over 18 m/s, respectively.