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Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*
Journal of Semiconductors, 39(8), p.082001_1 - 082001_5, 2018/08
Dynamic nuclear self-polarization (DYNASP) is a phenomenon observed in III-V semiconductors. When electrons of the valence band of a semiconductor are optically excited to the conduction band, a relaxation process of the conduction electrons induces a large nuclear polarization to suddenly occur below a critical temperature. Extending the original theoretical work of Dyakonov et al., we examined the effect of spin distribution of valence electrons excited by the circularly polarized light and the effect of external magnetic field on the phenomenon of the nuclear self-polarization. We found that the nuclear polarization is achieved even above the critical temperatures by the effect of electron polarization and of the external magnetic field. To investigate the phenomenon experimentally, we constructed an apparatus for low-temperature experiments.
Inoue, Takashi; Hanada, Masaya; Kashiwagi, Mieko; Nishio, Satoshi; Sakamoto, Keishi; Sato, Masayasu; Taniguchi, Masaki; Tobita, Kenji; Watanabe, Kazuhiro; DEMO Plant Design Team
Fusion Engineering and Design, 81(8-14), p.1291 - 1297, 2006/02
Times Cited Count：11 Percentile：61.17(Nuclear Science & Technology)Requirement and technical issues of the neutral beam inejctor (NBI) is discussed for fusion DEMO plant. The NBI for the fusion DEMO plant should be high efficiency, high energy and high reliability with long life. From the view point of high efficiency, use of conventional electrostatic accelerator is realistic. Due to operation under radiation environment, vacuum insulation is essential in the accelerator. According to the insulation design guideline, it was clarified that the beam energy of 1.5
2 MeV is possible in the accelerator. Development of filamentless, and cesium free ion source is required, based on the existing high current/high current density negative ion production technology. The gas neutralization is not applicable due to its low efficiency (60%). R&D on an advanced neutralization scheme such as plasma neutralization (efficiency: 
80%) is required. Recently, development of cw high power semiconductor laser is in progress. The paper shows a conceptual design of a high efficiency laser neutralizer utilizing the new semiconductor laser array.
