Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 57

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

The Joint evaluated fission and fusion nuclear data library, JEFF-3.3

Plompen, A. J. M.*; Cabellos, O.*; De Saint Jean, C.*; Fleming, M.*; Algora, A.*; Angelone, M.*; Archier, P.*; Bauge, E.*; Bersillon, O.*; Blokhin, A.*; et al.

European Physical Journal A, 56(7), p.181_1 - 181_108, 2020/07

 Times Cited Count:3 Percentile:11.65(Physics, Nuclear)

The Joint Evaluated Fission and Fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides $$^{235}$$U, $$^{238}$$U and $$^{239}$$Pu, on $$^{241}$$Am and $$^{23}$$Na, $$^{59}$$Ni, Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includes new fission yileds, prompt fission neutron spectra and average number of neutrons per fission. In addition, new data for radioactive decay, thermal neutron scattering, gamma-ray emission, neutron activation, delayed neutrons and displacement damage are presented. JEFF-3.3 was complemented by files from the TENDL project. The libraries for photon, proton, deuteron, triton, helion and alpha-particle induced reactions are from TENDL-2017. The demands for uncertainty quantification in modeling led to many new covariance data. A comparison between results from model calculations using the JEFF-3.3 library and those from benchmark experiments for criticality, delayed neutron yields, shielding and decay heat, reveals that JEFF-3.3 is excellent for a wide range of nuclear technology applications, in particular nuclear energy.

Journal Articles

$$^{239}$$Pu nuclear magnetic resonance in the candidate topological insulator PuB$$_4$$

Dioguardi, A. P.*; Yasuoka, Hiroshi*; Thomas, S. M.*; Sakai, Hironori; Cary, S. K.*; Kozimor, S. A.*; Albrecht-Schmitt, T. E.*; Choi, H. C.*; Zhu, J.-X.*; Thompson, J. D.*; et al.

Physical Review B, 99(3), p.035104_1 - 035104_6, 2019/01

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

We present a detailed nuclear magnetic resonance (NMR) study of $$^{239}$$Pu in bulk and powdered single-crystal plutonium tetraboride (PuB$$_4$$), which has recently been investigated as a potential correlated topological insulator. The $$^{239}$$Pu NMR spectra are consistent with axial symmetry of the shift tensor showing for the first time that $$^{239}$$Pu NMR can be observed in an anisotropic environment and up to room temperature. The temperature dependence of the $$^{239}$$Pu shift, combined with a relatively long spin-lattice relaxation time ($$T_1$$), indicate that PuB$$_4$$ adopts a nonmagnetic state with gaplike behavior consistent with our density functional theory calculations. The temperature dependencies of the NMR Knight shift and $$T^{-1}$$ imply bulk gaplike behavior confirming that PuB$$_4$$ is a good candidate topological insulator.

Journal Articles

Neutron-hole states in $$^{131}$$Sn and spin-orbit splitting in neutron-rich nuclei

Orlandi, R.; Pain, S. D.*; Ahn, S.*; Jungclaus, A.*; Schmitt, K. T.*; Bardayan, D. W.*; Catford, W. N.*; Chapman, R.*; Chipps, K. A.*; Cizewski, J. A.*; et al.

Physics Letters B, 785, p.615 - 620, 2018/10

 Times Cited Count:4 Percentile:37.52(Astronomy & Astrophysics)

Journal Articles

CIELO collaboration summary results; International evaluations of neutron reactions on uranium, plutonium, iron, oxygen and hydrogen

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.

Nuclear Data Sheets, 148, p.189 - 213, 2018/02

 Times Cited Count:21 Percentile:3.62(Physics, Nuclear)

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - $$^{235}$$U, $$^{238}$$U, $$^{239}$$Pu, $$^{56}$$Fe, $$^{16}$$O and $$^{1}$$H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.

Journal Articles

The CIELO collaboration; Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Kahler, A. C.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Pigni, M.*; Dunn, M.*; Leal, L.*; et al.

EPJ Web of Conferences, 146, p.02001_1 - 02001_9, 2017/09

 Times Cited Count:5 Percentile:1.48

The CIELO collaboration has studied neutron cross sections on nuclides ($$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U and $$^{239}$$Pu) that significantly impact criticality in nuclear technologies with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

Journal Articles

Anisotropy of spin fluctuations in a tetragonal heavy fermion antiferromagnet CeRhAl$$_4$$Si$$_2$$

Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ghimire, N. J.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Journal of Physics; Conference Series, 868(1), p.012012_1 - 012012_5, 2017/07

 Times Cited Count:1 Percentile:35

$$^{27}$$Al NMR experiments have been performed using a single crystal of CeRhAl$$_4$$Si$$_2$$. In the paramagnetic state, Knight shifts, quadrupolar frequency, and asymmetric parameter of electrical field gradient on the Al sites have been determined, which has a local orthorhombic symmetry. The transferred hyperfine coupling constants are also determined. The relaxation rates suggest that 4$$f$$ electrons behave as local moments in the high temperatures. From the NMR spectral analyses, the antiferromagnetic structures are discussed.

Journal Articles

Local moments in the heterogeneous electronic state of Cd-substituted CeCoIn$$_5$$; NQR relaxation rates

Sakai, Hironori; Ronning, F.*; Hattori, Takanori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Bauer, E. D.*; Thompson, J. D.*

Journal of Physics; Conference Series, 807(3), p.032001_1 - 032001_6, 2017/04

 Times Cited Count:0 Percentile:100

We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum critical metal CeCoIn$$_5$$ to substitutions of small amounts of Cd for In. Approximately half of the Cd substituents induce local Ce moments in their close proximity, as observed by site-dependent longitudinal nuclear spin relaxation rates $$1/T_1$$. To reaffirm that localized $$f$$ moments are induced around the Cd substituents, we find a Gaussian spin-echo decay rate $$1/T_{rm 2G}$$ of transverse nuclear spin relaxation. Further, $$T_1T/T_{rm 2G}^2$$ for the NQR subpeak is found to be proportional to temperatures, again indicating local moments fluctuations around the Cd substituents, while that for the NQR main peak shows a $$T^{0.7}$$-dependence. The latter temperature dependence is close to 0.75 in pure CeCoIn$$_5$$ and indicates that the bulk electronic state is located close to a two dimensional quantum critical instability.

Journal Articles

Stability and synthesis of superheavy elements; Fighting the battle against fission - Example of $$^{254}$$No

Lopez-Martens, A.*; Henning, G.*; Khoo, T. L.*; Seweryniak, D.*; Alcorta, M.*; Asai, Masato; Back, B. B.*; Bertone, P. F.*; Boilley, D.*; Carpenter, M. P.*; et al.

EPJ Web of Conferences, 131, p.03001_1 - 03001_6, 2016/12

 Times Cited Count:1 Percentile:47.47

Fission barrier height and its angular-momentum dependence have been measured for the first time in the nucleus with the atomic number greater than 100. The entry distribution method, which can determine the excitation energy at which fission starts to dominate the decay process, was applied to $$^{254}$$No. The fission barrier of $$^{254}$$No was found to be 6.6 MeV at zero spin, indicating that the $$^{254}$$No is strongly stabilized by the nuclear shell effects.

Journal Articles

Volume-wise destruction of the antiferromagnetic Mott insulating state through quantum tuning

Frandsen, B. A.*; Liu, L.*; Cheung, S. C.*; Guguchia, Z.*; Khasanov, R.*; Morenzoni, E.*; Munsie, T. J. S.*; Hallas, A. M.*; Wilson, M. N.*; Cai, Y.*; et al.

Nature Communications (Internet), 7, p.12519_1 - 12519_8, 2016/08

 Times Cited Count:13 Percentile:33.14(Multidisciplinary Sciences)

Journal Articles

Incommensurate to commensurate antiferromagnetism in CeRhAl$$_4$$Si$$_2$$; An $$^{27}$$Al NMR study

Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ghimire, N. J.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Physical Review B, 93(1), p.014402_1 - 014402_9, 2016/01

 Times Cited Count:1 Percentile:91.65(Materials Science, Multidisciplinary)

$$^{27}$$Al nuclear magnetic resonance (NMR) experiments have been performed on a single crystal of CeRhAl$$_4$$Si$$_2$$, which is an antiferromagnetic Kondo-lattice compound with successive antiferromagnetic transitions of $$T_{rm N1}$$=14 K and $$T_{rm N2}$$=9 K at zero external field. In the paramagnetic state, the Knight shifts, quadrupolar frequency, and asymmetric parameter of electrical field gradient on the Al sites have been determined, which have local orthorhombic symmetry. The transferred hyperfine coupling constants are also determined. Analysis of the NMR spectra indicates that a commensurate antiferromagnetic structure exists below $$T_{rm N2}$$, but an incommensurate modulation of antiferromagnetic moments is present in the antiferromagnetic state between $$T_{rm N1}$$ and $$T_{rm N2}$$. The spin-lattice relaxation rate suggests that the $$4f$$ electrons behave as local moments at temperatures above $$T_{rm N1}$$.

Journal Articles

Microscopic investigation of electronic inhomogeneity induced by substitutions in a quantum critical metal CeCoIn$$_5$$

Sakai, Hironori; Ronning, F.*; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Tokunaga, Yo; Kambe, Shinsaku; Bauer, E. D.*; Thompson, J. D.*

Physical Review B, 92(12), p.121105_1 - 121105_5, 2015/09

 Times Cited Count:13 Percentile:37.3(Materials Science, Multidisciplinary)

Chemical substitutions are used commonly to tune a magnetic transition to zero temperature, but the resulting non-Fermi liquid (NFL) behavior is non-universal. We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum-critical metal CeCoIn$$_5$$ to substitutions of small amounts of Sn and Cd for In. These substituents induce very different local electronic environments as observed by site dependent spin lattice relaxation rates $$1/T_1$$ that influence the NFL behavior. The effects found here illustrate the need for care in interpreting NFL properties determined by macroscopic measurements.

Journal Articles

Fission barrier of superheavy nuclei and persistence of shell effects at high spin; Cases of $$^{254}$$No and $$^{220}$$Th

Henning, G.*; Khoo, T. L.*; Lopez-Martens, A.*; Seweryniak, D.*; Alcorta, M.*; Asai, Masato; Back, B. B.*; Bertone, P. F.*; Boilley, D.*; Carpenter, M. P.*; et al.

Physical Review Letters, 113(26), p.262505_1 - 262505_6, 2014/12

 Times Cited Count:26 Percentile:16.35(Physics, Multidisciplinary)

Fission barrier heights of a shell-stabilized superheavy nucleus $$^{254}$$No have been determined as a function of spin up to 19$$hbar$$ through the measured distribution of entry points of $$gamma$$ deexcitations in the excitation energy vs. spin plane. The fission barrier height of $$^{254}$$No was determined to be 6.0 MeV at spin 15$$hbar$$, and 6.6 MeV at spin 0$$hbar$$ by extrapolation. This demonstrates that the shell effect actually enlarges the fission barrier in such heavy nuclei and keeps the barrier high even at high spin.

Journal Articles

Emergent antiferromagnetism out of the "hidden-order" state in URu$$_2$$Si$$_2$$; High magnetic field nuclear magnetic resonance to 40 T

Sakai, Hironori; Urbano, R. R.*; Tokunaga, Yo; Kambe, Shinsaku; Suzuki, Michito; Kuhns, P. L.*; Reyes, A. P.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; et al.

Physical Review Letters, 112(23), p.236401_1 - 236401_5, 2014/06

 Times Cited Count:7 Percentile:43.63(Physics, Multidisciplinary)

Very high field $$^{29}$$Si-NMR measurements using a fully $$^{29}$$Si-enriched URu$$_2$$Si$$_2$$ single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the $$^{29}$$Si shift, $$^{29}K_c$$. Moreover, a strong enhancement of $$^{29}K_c$$ develops near a critical field $$H_{rm c}simeq 35.6$$ T, and the $$^{29}$$Si-NMR signal disappears suddenly at $$H_{rm c}$$, indicating the total suppression of the HO state. Nevertheless, a weak and shifted $$^{29}$$Si-NMR signal reappears for fields higher than $$H_{rm c}$$ at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

Journal Articles

Coexistence of antiferromagnetism with superconductivity in CePt$$_2$$In$$_7$$; Microscopic phase diagram determined by $$^{115}$$In NMR and NQR

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Physical Review Letters, 112(20), p.206401_1 - 206401_5, 2014/05

 Times Cited Count:13 Percentile:29.02(Physics, Multidisciplinary)

Single crystals of the heavy-fermion antiferromagnet CePt$$_{2}$$In$$_{7}$$ with a N$'e$el temperature ($$T_{N}$$) of 5.2 K at ambient pressure have been investigated by zero-field $$^{115}$$In-nuclear magnetic/quadrupole resonance (NMR/NQR) measurements as a function of applied pressure. Within the antiferromagnetic state the character of Ce's $$4f$$ electron appears to change from localized to itinerant-like at $$P^astsim2.4$$ GPa, approximately the pressure where superconductivity first emerges. With increased pressure, the superconducting transition $$T_{c}$$ reaches a maximum just at or slighty before antiferromagnetic order disappears, and not at the pressure $$P_{c}sim 3.4$$ GPa where the steeply decreasing N$'e$el boundary extrapolates to zero temperature. For $$P>P_{c}$$, the spin relaxation rate drops sharply by more than two orders of magnitude at $$T_{c}$$, suggestive of a first order transition.

Journal Articles

The CIELO Collaboration; Neutron reactions on $$^1$$H, $$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U, and $$^{239}$$Pu

Chadwick, M. B.*; Dupont, E.*; Bauge, E.*; Blokhin, A.*; Bouland, O.*; Brown, D. A.*; Capote, R.*; Carlson, A. D.*; Danon, Y.*; De Saint Jean, C.*; et al.

Nuclear Data Sheets, 118, p.1 - 25, 2014/04

 Times Cited Count:88 Percentile:1.08(Physics, Nuclear)

CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. The focus will initially be on a small number of the highest-priority isotopes, namely $$^{1}$$H, $$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U, and $$^{239}$$Pu. This paper identifies discrepancies between various evaluations of the highest priority isotopes. The evaluated data for these materials in the existing nuclear data libraries are reviewed, and some integral properties are given. The paper summarizes a program of nuclear science and computational work needed to create the new CIELO nuclear data evaluations.

Journal Articles

Exploring the stability of super heavy elements; First measurement of the fission barrier of $$^{254}$$No

Henning, G.*; Lopez-Martens, A.*; Khoo, T. L.*; Seweryniak, D.*; Alcorta, M.*; Asai, Masato; Back, B. B.*; Bertone, P. F.*; Boilley, D.*; Carpenter, M. P.*; et al.

EPJ Web of Conferences, 66, p.02046_1 - 02046_8, 2014/03

 Times Cited Count:3 Percentile:22.93

Fission barrier heights of $$^{254}$$No have been determined through the entry distribution method. The entry distribution is the initial distribution of excitation energy and spin from which the $$gamma$$ deexcitation starts in the fusion-evaporation reaction. The initial distribution is extracted from measured $$gamma$$-ray multiplicity and total $$gamma$$-ray energy. This paper describes the details of the entry distribution method, and reports the first determination of the fission barrier heights of $$^{254}$$No, which is the heaviest nucleus whose fission barrier has been measured.

Journal Articles

Diluted ferromagnetic semiconductor Li(Zn,Mn)P with decoupled charge and spin doping

Deng, Z.*; Zhao, K.*; Gu, B.; Han, W.*; Zhu, J. L.*; Wang, X. C.*; Li, X.*; Liu, Q. Q.*; Yu, R. C.*; Goko, Tatsuo*; et al.

Physical Review B, 88(8), p.081203_1 - 081203_5, 2013/08

 Times Cited Count:60 Percentile:6.9(Materials Science, Multidisciplinary)

Journal Articles

First prompt in-beam $$gamma$$-ray spectroscopy of a superheavy element; The $$^{256}$$Rf

Rubert, J.*; Dorvaux, O.*; Gall, B. J. P.*; Greenlees, P. T.*; Asfari, Z.*; Piot, J.*; Andersson, L. L.*; Asai, Masato; Cox, D. M.*; Dechery, F.*; et al.

Journal of Physics; Conference Series, 420, p.012010_1 - 012010_10, 2013/03

 Times Cited Count:0 Percentile:100

The first prompt in-beam $$gamma$$-ray spectroscopy of a superheavy element, $$^{256}$$Rf, has been performed successfully. A development of an intense isotopically enriched $$^{50}$$Ti beam using the MIVOC method enabled us to perform this experiment. A rotational band up to a spin of 20 $$hbar$$ has been discovered in $$^{256}$$Rf, and its moment of inertia has been extracted. These data suggest that there is no evidence of a significant deformed shell gap at $$Z$$ = 104.

Journal Articles

NMR/NQR Study of pressure-induced superconductor CePt$$_2$$In$$_7$$

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Lee, H.*; Sidorov, V. A.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Journal of Physics; Conference Series, 391, p.012057_1 - 012057_4, 2012/12

 Times Cited Count:4 Percentile:15.39

Zero-field $$^{115}$$In-nuclear magnetic resonance (NMR) has been used to study single crystals of CePt$$_2$$In$$_7$$, a heavy-fermion antiferromagnet with a N$'e$el temperature ($$T_{rm N}$$) of 5.2 K at ambient pressure. The NMR spectra under zero field near the 3$$nu_{rm Q}$$ line of the orthorhombic In(3) sites are tracked by temperatures down to 1.6 K and by hydrostatic pressures up to 2.4 GPa. These data reveal the coexistence of commensurate (C) and incommensurate (IC) antiferromagneic orders at ambient pressure and that the C-AFM ordering is stabilized by increasing pressures where bulk superconductivity emerges. We will show the recent data of spectra and nuclear relaxation rates ($$1/T_1$$) under pressures.

Journal Articles

Anisotropic spin fluctuations in the heavy fermion systems; Case studies of CePd$$_5$$Al$$_2$$ and NpPd$$_5$$Al$$_2$$

Sakai, Hironori; Chudo, Hiroyuki; Tokunaga, Yo; Kambe, Shinsaku; Haga, Yoshinori; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*; Homma, Yoshiya*; Aoki, Dai*; et al.

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB003_1 - SB003_6, 2012/12

 Times Cited Count:5 Percentile:57.42(Physics, Multidisciplinary)

In the so-called 115 family members with chemical formulae of Ce$$T$$In$$_5$$ ($$T$$=Co, Rh, Ir) and $$An$$$$T$$Ga$$_5$$ ($$An$$=U, Np, Pu), our analysis of the Knight shift and spin-lattice relaxation rates suggests that larger XY-type anisotropy in the antiferromagnetic spin fluctuations in the normal states would favor $$d$$-wave superconductivity with higher $$T_c$$. In order to examine this working hypothesis, the anisotropy ratios of antiferromagnetic fluctuations are derived from our NMR results for the superconductor NpPd$$_5$$Al$$_2$$ and antiferromagnet CePd$$_5$$Al$$_2$$, which are tetragonal compounds with a 115-related structure. CePd$$_5$$Al$$_2$$ shows Ising-type anisotropy, which is the same anisotropy as in the ordered state. On the other hand, NpPd$$_5$$Al$$_2$$ shows XY-type anisotropy just above $$T_c$$.

57 (Records 1-20 displayed on this page)