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山下 真一郎; 永瀬 文久; 倉田 正輝; 野澤 貴史; 渡部 清一*; 桐村 一生*; 垣内 一雄*; 近藤 貴夫*; 坂本 寛*; 草ヶ谷 和幸*; et al.
Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09
我が国では、事故耐性燃料の技術基盤を整備するために2015年に軽水炉の事故耐性燃料等(ATFs)に関する研究開発プロジェクトが立ち上がった。日本原子力研究開発機構は、国内のプラントメーカ, 燃料メーカ, 大学等が有する国内軽水炉においてジルカロイを商用利用した際の経験、知識を最大限活用するために、これらの機関と協力して本プロジェクトを実施するとともに取りまとめを行っている。プロジェクトの中で検討されているATF候補材料は、微細な酸化物粒子を分散することで強化されたFeCrAl鋼(FeCrAl-ODS鋼)と炭化ケイ素(SiC)複合材料であり、通常運転時の燃料性能は同等かそれ以上で、事故時にはジルカロイよりも長い時間原子炉炉心においてシビアアクシデント条件に耐えることが期待されている。本論文では、日本のプロジェクトで実施中の研究開発の進捗について報告する。
Christle, D.*; Falk, A.*; Andrich, A.*; Klimov, P.*; Hassan, J.*; Son, N. T.*; Janz
n, E.*; 大島 武; Awschalom, D.*
Nature Materials, 14(2), p.160 - 163, 2015/02
被引用回数：332 パーセンタイル：99.2(Chemistry, Physical)Carbon vacancy - silicon vacancy pair (V
-V
) in silicon carbide (SiC) is regarded as a promising candidate for a qubit for quantum computing since V-V is thought to have electronic states with sharp optical and spin transitions. However, single spin operation using V-V has not yet been succeeded although it was revealed that V-V shows the characteristics as a single photon source (SPS). In this study, we studied spin properties of V-V created in SiC by 2 MeV-electron irradiation. First, we found V-V in SiC using a confocal microscope (CFM) and measured their optical detected magnet resonance (ODMR) at 20 K. Then, their spin coherence was measured from the standard two-pulse Hahn-echo sequence using ODMR. As a result, the spin coherence time exceeding 1 ms was obtained.
Widmann, M.*; Lee, S.-Y.*; Rendler, T.*; Son, N. T.*; Fedder, H.*; Paik, S.*; Yang, L.-P.*; Zhao, N.*; Yang, S.*; Booker, I.*; et al.
Nature Materials, 14(2), p.164 - 168, 2015/02
被引用回数：438 パーセンタイル：99.56(Chemistry, Physical)Single silicon vacancy (V) in silicon carbide (SiC) was studied from the point of view of single photon source for quantum computing. The V centers were created in high purity semi-insulating hexagonal (4H)-SiC by 2 MeV electron irradiation with fluences up to 5
10
/cm
. No subsequent annealing was carried out. A couple of solid immersion lens (SIL) with 20 
m diameter were created on samples by ion milling using 40 keV Ga focused ion beam. A typical home-built confocal setup was used after optimizing for emission in the wavelength range around 900 nm. As a result, optically detected electron spin resonance (ODMR) for V was observed at room temperature (RT). Using ODMR, Rabi oscillations were also observed, and the Rabi frequency increased with increasing applied-magnetic field. In addition, spin relaxation time T
and T
were detected to be 500 s and 160 s, respectively.
