Since 2009, the Spallation Neutron Source (SNS) has been producing neutrons with ion beam powers near 1 MW, which requires the extraction of ∼50 mA H(-) ions from the ion source with a ∼5% duty factor. The 50 mA are achieved after an initial dose of ∼3 mg of Cs and heating the Cs collar to ∼170 °C. The 50 mA normally persist for the entire 4-week source service cycles. Fundamental processes are reviewed to elucidate the persistence of the SNS H(-) beams without a steady feed of Cs and why the Cs collar temperature may have to be kept near 170 °C.
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http://dx.doi.org/10.1063/1.3681921 | DOI Listing |
Sci Rep
January 2025
Research Institute of Interdisciplinary Science, School of Materials Science and Engineering, Dongguan University of Technology, Dongguan, 523808, China.
Manufacturing of metallic components using additive manufacturing technique is of great interest for the industrial applications. Here, the mechanical and microstructural responses of a 316 L stainless steel (316LSS) built by selective laser melting (SLM) with XOY and XOZ directions were revealed by performing in situ neutron diffraction tensile tests. The tensile strength of the XOY-printed samples reaches 700 MPa, while the tensile strength of the XOZ-printed samples is less than 600 MPa.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
CuO octahedra usually show elongated distortion, leading to active orbitals and planar exchange interactions, while compressed CuO octahedra with active orbitals and unidirectional exchange interactions are exceptionally rare. Here, we design and synthesize a new frustrated antiferromagnet CaCuFeO through a high-pressure and high-temperature approach, in which robust compressed CuO octahedra are realized, separating the FeO sheets that comprise zigzag spin ladders. Magnetic susceptibility and specific heat measurements exhibit a long-range antiferromagnetic order below the Néel temperature of 165 K, which is further confirmed by neutron diffraction.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Physical Chemistry, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Lattice distortion and disorder in the chemical environment of magnetic atoms within high-entropy compounds present intriguing issues in the modulation of magnetic functional compounds. However, the complexity inherent in high-entropy disordered systems has resulted in a relative scarcity of comprehensive investigations exploring the magnetic functional mechanisms of these alloys. Herein, we investigate the magnetocaloric effect (MCE) of the high-entropy intermetallic compound GdTbDyHoErCo.
View Article and Find Full Text PDFNat Mater
January 2025
School of Physics, Zhejiang University, Hangzhou, China.
In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose-Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into bound states under attractive interactions. The Zeeman coupling to a magnetic field is able to tune the particle density through a quantum critical point, beyond which a 'hidden order' is predicted to exist.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
The Pd-Zn γ-brass phase provides exciting opportunities for synthesizing site-isolated catalysts with precisely controlled Pd active site ensembles. Introducing a third metallic element into the γ-brass lattice further perturbs the catalytic active site ensembles. Here, we introduce coinage metallic elements M (M = Cu, Ag, and Au) into the Pd-Zn γ-brass phase and investigate the site occupation factors of each element in the γ-brass lattice.
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