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The $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross section from the surrogate ratio method and its effect on the $$^{60}$$Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; 西尾 勝久; Lugaro, M.*; Li, Z. H.*; 牧井 宏之; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; 廣瀬 健太郎; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10


The long-lived $$^{60}$$Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe on $$^{59}$$Fe (half-life=44.5 days) is the key reaction for the production of $$^{60}$$Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the E1 $$gamma$$-ray strength function but a negligible constraint on the M1 and E2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5$$pm$$3.5 mb at $$kT$$ = 30 keV and 13.4$$pm$$1.7 mb at $$kT$$ = 90 keV, roughly 10%-20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of $$^{60}$$Fe from the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe rate are at most 25$$%$$. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of $$^{60}$$Fe.


Coexistence of ferromagnetic and stripe-type antiferromagnetic spin fluctuations in YFe$$_{2}$$Ge$$_{2}$$

Wo, H.*; Wang, Q.*; Shen, Y.*; Zhang, X.*; Hao, Y.*; Feng, Y.*; Shen, S.*; He, Z.*; Pan, B.*; Wang, W.*; et al.

Physical Review Letters, 122(21), p.217003_1 - 217003_5, 2019/05

 被引用回数:2 パーセンタイル:35.62(Physics, Multidisciplinary)

We report neutron scattering measurements of single-crystalline YFe$$_{2}$$Ge$$_{2}$$ in the normal state, which has the same crystal structure as the 122 family of iron pnictide superconductors. YFe$$_{2}$$Ge$$_{2}$$ does not exhibit long-range magnetic order but exhibits strong spin fluctuations. Like the iron pnictides, YFe$$_{2}$$Ge$$_{2}$$ displays anisotropic stripe-type antiferromagnetic spin fluctuations at ($$pi, 0, pi$$). More interesting, however, is the observation of strong spin fluctuations at the in-plane ferromagnetic wave vector ($$0, 0, pi$$). These ferromagnetic spin fluctuations are isotropic in the ($$H, K$$) plane, whose intensity exceeds that of stripe spin fluctuations. Both the ferromagnetic and stripe spin fluctuations remain gapless down to the lowest measured energies. Our results naturally explain the absence of magnetic order in YFe$$_{2}$$Ge$$_{2}$$ and also imply that the ferromagnetic correlations may be a key ingredient for iron-based materials.


Magnon polarons in the spin Seebeck effect

吉川 貴史*; Shen, K.*; Flebus, B.*; Duine, R. A.*; 内田 健一*; Qiu, Z.*; Bauer, G. E. W.*; 齊藤 英治

Physical Review Letters, 117(20), p.207203_1 - 207203_6, 2016/11

 被引用回数:87 パーセンタイル:96.97(Physics, Multidisciplinary)

Sharp structures in the magnetic field-dependent spin Seebeck effect (SSE) voltages of Pt/Y$$_{3}$$Fe$$_{5}$$O$$_{12}$$ at low temperatures are attributed to the magnon-phonon interaction. Experimental results are well reproduced by a Boltzmann theory that includes magnetoelastic coupling. The SSE anomalies coincide with magnetic fields tuned to the threshold of magnon-polaron formation. The effect gives insight into the relative quality of the lattice and magnetization dynamics.


From a single-band metal to a high-temperature superconductor via two thermal phase transitions

He, R.-H.*; 橋本 真*; Karapetyan, H.*; Koralek, J. D.*; Hinton, J. P.*; Testaud, J. P.*; Nathan, V.*; 吉田 良行*; Yao, H.*; 田中 清尚*; et al.

Science, 331(6024), p.1579 - 1583, 2011/03

 被引用回数:252 パーセンタイル:98.82(Multidisciplinary Sciences)



Unified beam control system of J-PARC linac

佐甲 博之; Allen, C. K.*; 池田 浩*; Shen, G.*

IEEE Transactions on Nuclear Science, 57(3), p.1528 - 1535, 2010/06

 被引用回数:0 パーセンタイル:0.01(Engineering, Electrical & Electronic)



Beam commissioning software and database for J-PARC LINAC

佐甲 博之; 榊 泰直; Shen, G.; 高橋 博樹; 吉川 博; 池田 浩*; Allen, C. K.*

Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS '07) (CD-ROM), p.698 - 700, 2007/10




藤森 伸一; Mo, S.-K.*; 田中 清尚*; Hussain, Z.*; Shen, Z. X.*; 藤森 淳; 山上 浩志; 摂待 力生*; 大貫 惇睦*

no journal, , 

反転対称性を持たない重い電子系超伝導体CeIrSi$$_3$$に対して行った高分解能角度分解光電子分光の結果について報告する。CeIrSi$$_3$$は結晶構造に反転対称性を持たないために各バンドがスピン軌道相互作用によって1000K程度の分裂を起こし、詳細な電子構造の観測には高いエネルギー分解能が必要となる。そこで米国の放射光施設Advanced Light Source BL 10.0.1において$$hnu$$=95-122eVの入射光を用い、30meV程度の高エネルギー分解能で角度分解光電子分光測定を行った。実験の結果、EF付近に4f電子が形成する平坦な準粒子が観測されているが、dバンドが$$E_F$$を横切る位置で混成を起こして強度変化を示していることが明らかとなった。このことから、4f電子は局在的ではなく、d電子と混成してフェルミ面を形成していることが明らかとなった。バンド計算との比較に基づき、この化合物の電子状態について議論する。

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