Multiple mechanisms in proton-induced nucleon removal at 100 MeV/nucleon

Pohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; Gmez-Ramos, M.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.

Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04

https://doi.org/10.1103/PhysRevLett.130.172501

We report on the first proton-induced single proton- and neutron-removal reactions from the neutron deficient O nucleus with large Fermi-surface asymmetry at 100 MeV/nucleon. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively.

Overview of the OECD-NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC)

Fleming, M.*; Bernard, D.*; Brown, D.*; Chadwick, M. B.*; De Saint Jean, C.*; Dupont, E.*; Ge, Z.*; Harada, Hideo; Hawari, A.*; Herman, M.*; et al.

EPJ Web of Conferences, 239, p.15002_1 - 15002_4, 2020/09

https://doi.org/10.1051/epjconf/202023915002

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

https://doi.org/10.1016/j.nds.2018.02.003

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - U, U, Pu, Fe, O and 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.

A New view of the tree of life

Hug, L. A.*; Baker, B. J.*; Anantharaman, K.*; Brown, C. T.*; Probst, A. J.*; Castelle, C. J.*; Butterfield, C. N.*; Hernsdorf, A. W.*; Amano, Yuki; Ise, Kotaro; et al.

Nature Microbiology (Internet), 1(5), p.16048_1 - 16048_6, 2016/05

https://doi.org/10.1038/nmicrobiol.2016.48

The tree of life is one of the most important organizing principles in biology. Gene surveys suggest the existence of an enormous number of branches, but even an approximation of the full scale of The Tree has remained elusive. Here, we use newly available information from genomes of uncultivated organisms, along with other published sequences, to present a new version of the Tree of life, with Bacteria, Archaea and Eukaryotes included. The depiction is both a global overview and a snapshot of the diversity within each major lineage. The results imply the predominance of bacterial diversification and underline the importance of organisms lacking isolated representatives, with substantial evolution concentrated in a major radiation of such organisms.

The CIELO Collaboration; Neutron reactions on H, O, Fe, U, and 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

https://doi.org/10.1016/j.nds.2014.04.002

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 H, O, Fe, U, and 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.

ENDF/B-VII.1 nuclear data for science and technology; Cross sections, covariances, fission product yields and decay data

Chadwick, M. B.*; Herman, M.*; Obloinsk, P.*; Dunn, M. E.*; Danon, Y.*; Kahler, A. C.*; Smith, D. L.*; Pritychenko, B.*; Arbanas, G.*; Arcilla, R.*; et al.

Nuclear Data Sheets, 112(12), p.2887 - 2996, 2011/12

https://doi.org/10.1016/j.nds.2011.11.002

The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. It features extension of covered nuclei, covariance data for 190 nuclei, R-matrix analyses of neutron reactions on light nuclei, updates for some medium-heavy and actinoid nuclei, etc. Criticality benchmark tests with a transport simulation code MCNP shows improved performances.

Magnetic-field-induced enhancement of nuclear spin-lattice relaxation rates in the heavy-fermion superconductor CeCoIn using Co nuclear magnetic resonance

Sakai, Hironori; Brown, S. E.*; Baek, S.-H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

Physical Review Letters, 107(13), p.137001_1 - 137001_5, 2011/09

https://doi.org/10.1103/PhysRevLett.107.137001

Co nuclear spin lattice relaxation has been measured for the heavy-fermion superconductor CeCoIn in a range of applied fields directed parallel to the -axis. An enhanced normal state relaxation rate, observed at low temperatures and fields just above , is taken as a direct measure of the dynamical susceptibility and provides microscopic evidence for an antiferromagnetic instability. The results are well-described using the self-consistent renormalized theory for two-dimensional antiferromagnetic spin fluctuations, and parameters obtained in the analysis are applied to previously reported specific heat and thermal expansion data with good agreement.

Two-proton knockout from Mg; Intruder amplitudes in Ne and implications for the binding of F

Fallon, P.*; Rodriguez-Vieitez, E.*; Macchiavelli, A. O.*; Gade, A.*; Tostevin, J. A.*; Adrich, P.*; Bazin, D.*; Bowen, M.*; Campbell, C. M.*; Clark, R. M.*; et al.

Physical Review C, 81(4), p.041302_1 - 041302_5, 2010/04

https://doi.org/10.1103/PhysRevC.81.041302

no abstracts in English

Structural characterization and dielectric properties of hexagonal Lu(Fe,Ti)O

Matsuo, Yoji*; Hoshiyama, Takuya*; Mori, Shigeo*; Yoshii, Kenji; Michiue, Yuichi*; Kambe, Takashi*; Ikeda, Naoshi*; Brown, F.*; Kimizuka, Noboru*

Japanese Journal of Applied Physics, 48(9), p.09KB04_1 - 09KB04_3, 2009/10

https://doi.org/10.1143/JJAP.48.09KB04

We have investigated an average crystal structure and microstructures in LuFeTiO by the transmission electron microscopy (TEM), in combination with the dielectric measurements. In this work, high-qualitypolycrystalline samples of LuFeTiO were successfully synthesized in air by the conventional solid state reaction. The average crystal structure at room temperature is characterized by the hexagonal structure (space group: 6 cm). Dielectric measurements revealed that LuFeTiO shows broad dielectric dispersion around 570 K, which should originate from the formation of the polar domain structures on the nanometer scale.

Recent results in fragmentation isomer spectroscopy with rising

Pietri, S.*; Regan, P. H.*; Podolyk, Zs.*; Rudolph, D.*; Steer, S. J.*; Garnsworthy, A. B.*; Werner-Malento, E.*; Hoischen, R.*; Grska, M.*; Gerl, J.*; et al.

Nuclear Instruments and Methods in Physics Research B, 261(1-2), p.1079 - 1083, 2007/08

https://doi.org/10.1016/j.nimb.2007.04.219

The first results from the stopped beam RISING experimental campaign performed at the GSI laboratory in Darmstadt, Germany, are presented. RISING constitutes a major new experimental program in European nuclear structure physics research aimed at using relativistic energy (typically around 1 GeV per nucleon) projectile fragmentation reactions to populate nuclei with highly exotic proton-to-neutron ratios compared to the line of beta stability. In its high-efficiency stopped beam configuration, the RISING -ray spectrometer consists of 105 individual germanium crystals which view a focal plane in which the exotic nuclei are brought to rest. Here, decays from metastable states with half-lives in the nano to milliseconds range can be observed. Results of initial commissioning experiments are also shown and details of the planned future experimental program are given.