Neutron diffraction; A Primer

Dronskowski, R.*; Brckel, T.*; Kohlmann, H.*; Avdeev, M.*; Houben, A.*; Meven, M.*; Hofmann, M.*; Kamiyama, Takashi*; Zobel, M.*; Schweika, W.*; et al.

Zeitschrift fr Kristallographie; Crystalline Materials, 239(5-6), p.139 - 166, 2024/06

https://doi.org/10.1515/zkri-2024-0001

Because of the neutron's special properties, neutron diffraction may be considered one of the most powerful techniques for structure determination of crystalline and related matter. Neutrons can be released from nuclear fission, from spallation processes, and also from low-energy nuclear reactions, and they can then be used in powder, time-of-flight, texture, single crystal, and other techniques, all of which are perfectly suited to clarify crystal and magnetic structures. With high neutron flux and sufficient brilliance, neutron diffraction also excels for diffuse scattering, for in situ and operando studies as well as for high-pressure experiments of today's materials. In this primer, we summarize the current state of neutron diffraction (and how it came to be), but also look at recent advances and new ideas, e.g., the design of new instruments, and what follows from that.

PANDORA Project for the study of photonuclear reactions below

Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.

European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09

https://doi.org/10.1140/epja/s10050-023-01081-w

no abstracts in English

Level structures of Ca cast doubt on a doubly magic Ca

Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.

Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08

https://doi.org/10.1016/j.physletb.2023.138025

Gamma decays were observed in Ca and Ca following quasi-free one-proton knockout reactions from Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the and orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to Ca or even beyond.

Decay spectroscopy of Eu; Quasiparticle configurations of excited states and structure of = 4 bandheads in Gd

Yates, D.*; Krcken, R.*; Dillmann, I.*; Garrett, P. E.*; Smallcombe, J.; 44 of others*

Physical Review C, 107(6), p.064309_1 - 064309_20, 2023/06

https://doi.org/10.1103/PhysRevC.107.064309

"Southwestern" boundary of the island of inversion; First study of low-lying bound excited states in V and V

Elekes, Z.*; Juhsz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.

Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12

https://doi.org/10.1103/PhysRevC.106.064321

The low-lying level structure of V and V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V while the neutron knock-out reaction provided the data for V. Four and five new transitions were determined for V and V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2 and 9/2 levels. The (,) excitation cross sections for V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V could not be unambiguously placed on the island of inversion.

Mechanical surface treatment studies by Bragg edge neutron imaging

Ramadhan, R. S.*; Glaser, D.*; Soyama, Hitoshi*; Kockelmann, W.*; Shinohara, Takenao; Pirling, T.*; Fitzpatrick, M. E.*; Tremsin, A. S.*

Acta Materialia, 239, p.118259_1 - 118259_12, 2022/10

https://doi.org/10.1016/j.actamat.2022.118259

On the adsorption and reactivity of element 114, flerovium

Yakushev, A.*; Lens, L.*; Dllmann, Ch. E.*; Khuyagbaatar, J.*; Jger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; Asai, Masato; Block, M.*; et al.

Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08

https://doi.org/10.3389/fchem.2022.976635

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. The first chemical experiment on Fl suggested that Fl is a noble-gas-like element, while the second studies suggested that Fl has a volatile-metal-like character. To obtain more reliable conclusion, we performed further experimental studies on Fl adsorption behavior on Si oxide and gold surfaces. The present results suggest that Fl is highly volatile and less reactive than the volatile metal, Hg, but has higher reactivity than the noble gas, Rn.

CSNI leak-before-break benchmark; Summary of phase 1

Tregoning, R.*; Wallace, J.*; Bouydo, A.*; Costa-Garrido, O.*; Dillstrm, P.*; Duan, X.*; Heckmann, K.*; Kim, Y.-B.*; Kim, Y.*; Kurth-Twombly, E.*; et al.

Transactions of the 26th International Conference on Structural Mechanics in Reactor Technology (SMiRT-26) (Internet), 11 Pages, 2022/07

Fourteen organizations, representing eleven countries, participated in a leak-before-break (LBB) benchmark exercise that compared results from analyses among participating countries and identified the effects of weld residual stress (WRS) and crack morphology on crack opening displacement (COD), critical bending moment (CBM), and leak rate (LR) results. The participants determined whether the initial problem would meet their country's LBB acceptance criteria and then evaluated the effects of crack morphology and WRS for a prescribed crack size, geometry and loading. Six out of fourteen participants indicated that the initial problem met their LBB requirements. In the follow-on tasks, differences among the participant's CBM predictions were principally due to the material properties used in the analysis while the type of failure model chosen contributed much less. Most of the differences in the LR predictions were directly attributable to differences among the COD models, but a portion was attributable to the treatment of crack face pressure (CFP). The benchmark identified several aspects of an LBB analysis that could support a more realistic evaluation.

A First glimpse at the shell structure beyond Ca; Spectroscopy of K, Ca, and Ca

Koiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navrtil, P.*; Ogata, Kazuyuki*; et al.

Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04

AA2021-0775.pdf:0.62MB

https://doi.org/10.1016/j.physletb.2022.136953

no abstracts in English

Unveiling unconventional magnetism at the surface of SrRuO

Fittipaldi, R.*; Hartmann, R.*; Mercaldo, M. T.*; Komori, Sachio*; Bjrlig, A.*; Higemoto, Wataru; Maeno, Yoshiteru*; Di Bernardo, A.*; 18 of others*

Nature Communications (Internet), 12, p.5792_1 - 5792_9, 2021/10

https://doi.org/10.1038/s41467-021-26020-5

The layered oxide perovskite SrRuO, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in SrRuO is still ongoing, a deeper understanding of the SrRuO normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in SrRuO at an onset temperature higher than 50 K. Our observations set a reference for the discovery of the same magnetic phase in other materials.