Depth-resolved magnetic and structural analysis of relaxing epitaxial Sr 2 CrReO 6
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We find that the proton separation energy, S(p), of 73 Rb is –640(40) keV, deduced from the observation of β-delayed ground-state protons following the decay of 73 Sr. This lower-limit determination of the proton separation energy of 73 Rb coupled with previous upper limits from nonobservation, provides a full constraint on the mass excess with ΔM ( 73 Rb) = –46.01 ± 0.04 MeV. With this new mass excess and the excitation energy of the J π = 5/2 – isobaric-analog state (T = 3/2) in 73 Rb, an improved constraint can be put on the mass excess of 73Sr using the isobaric-multiplet mass equation (IMME), and we find ΔM( 73 Sr) = –31.98 ± 0.37 MeV. Furthermore, these new data were then used to study the composition of ashes on accreting neutron stars following Type I x-ray bursts. Counterintuitively, we find that there should be an enhanced fraction of A > 102 nuclei with more negative proton separation energies at the 72 Kr rp-process waiting point. Larger impurities of heavier nuclei in the ashes of accreting neutron stars will impact the cooling models for such astrophysical scenarios.
The 5d 1 ordered double perovskites present an exotic playground for studying novel multipolar physics due to large spin-orbit coupling. Here, we present Re L 3 edge resonant inelastic Xray scattering (RIXS) results that reveal the presence of the dynamic Jahn-Teller effect in the A 2 MgReO 6 (A = Ca, Sr, Ba) family of 5d 1 double perovskites. The spin-orbit excitations in these materials show a strongly asymmetric lineshape and exhibit substantial temperature dependence, indicating that they are dressed with lattice vibrations. Our experimental results are explained quantitatively through a RIXS calculation based on a spin-orbit-lattice entangled electronic ground state with the dynamic Jahn-Teller effect taken into consideration. We find that the spin-orbitlattice entangled state is robust against magnetic and structural phase transitions as well as against significant static Jahn-Teller distortions. Our results illustrate the importance of including vibroniccoupling for a complete description of the ground state physics of 5d 1 double perovskites.
Single crystals of the single Kagome layer compound FeSn are investigated using xray and neutron scattering, magnetic susceptibility and magnetization, heat capacity, resistivity, Hall, Seebeck, thermal expansion, thermal conductivity measurements and density functional theory (DFT). FeSn is a planar antiferromagnet below T N = 365 K and exhibits ferromagnetic magnetic order within each Kagome layer. The in-plane magnetic susceptibility is sensitive to synthesis conditions. Resistivity, Hall and Seebeck results indicate multiple bands near the Fermi energy. The resistivity of FeSn is ≈ 3 times lower for current along the stacking direction than in the plane, suggesting that transport and the bulk electronic structure of FeSn is not quasi 2D. FeSn is an excellent metal with ρ(300K)/ρ(2K) values ≈100 in both directions. While the ordered state is antiferromagnetic, high temperature susceptibility measurements indicate a ferromagnetic Curie-Weiss temperature of 173 K, reflecting the strong in-plane ferromagnetic interactions. DFT calculations show a 3D electronic structure with the Dirac nodal lines along the K-H directions in the magnetic Brillouin zone about 0.3 eV below the Fermi energy, with the Dirac dispersions at the K points gapped by spin-orbit coupling except at the H point. The magnetism, however, is highly 2D with J in-plane /J out-of-plane ≈ 10. In conclusion, the predicted spin-wave spectrum is presented.
Hydrothermal diamond anvil cells (HDACs) provide facile means for coupling synchrotron Xray techniques with pressure up to 10 GPa and temperature up to 1300 K. This manuscript reports on an application of the HDAC as an ambient-pressure sample environment for performing in situ defect annealing and thermal expansion studies of swift heavy ion irradiated CeO 2 and ThO 2 using synchrotron X-ray diffraction. The advantages of the in situ HDAC technique over conventional annealing methods include: rapid temperature ramping and quench times, high-resolution measurement capability, simultaneous annealing of multiple samples, and prolonged temperature- and apparatus stability at high temperatures. Isochronal annealing between 300 K and 1100 K revealed 2-stage and 1-stage defect recovery processes for irradiated CeO 2 and ThO 2 , respectively; indicating that the morphology of the defects produced by swift heavy ion irradiation of these two materials differs significantly. These results suggest that electronic configuration plays a major role in both the radiation-induced defect production and high temperature defect recovery mechanisms of CeO 2 and ThO 2 .
A beam-driven structure wakefield accelerator (SWFA) is currently under consideration for future multi-user Xray free-electron-laser (FEL) light sources. One of the challenges associated with SWFA is the efficient energy transfer from the drive to the main bunch that can be enhanced via a precise control over the drive-bunch current profile. This paper discusses the development and initial beam-dynamics simulation of the drivebunch longitudinal dynamics using the fast-tracking program TWICE. This code, written in PYTHON, allows for rapid prototyping of the beam shaping process while taking into account the collective effects using simplified models. This paper describes the algorithm implementation and its capabilities of including collective effects into both forward and backward tracking. Initial results of optimizing beam shape with a conventional linac to produce a drive beam with a shape optimized for SFWA are presented.
We have been exploring the graphene field-effect transistor (GFET) as a platform for detection of ionizing radiation, whereby the detection is achieved indirectly by use of the field effect in graphene, which is induced by the generation and transport of ionized charge carriers in the underlying undoped semiconductor substrate. An important characteristic of such a detector is scalability to large areas. Previous experimental studies suggest that the effective area significantly exceeds the size of graphene for field effect-based architectures, and this is also predicted from the operational principle of these devices. We describe the results of the experimental studies of GFETs on silicon carbide (SiC) substrates by use a microbeam Xray facility, provided by the Advanced Photon Source at Argonne National Laboratory. The results confirm that the effective area of the GFET is significantly larger than that of graphene with response measured at distances as large as 1000 μm from 10-μm size graphene. A simple transport model has been developed and is used to explain the spatial dependence of the GFET response. (authors)
Synchrotron-based X-ray diffraction (XRD) and small-angle Xray scattering (SAXS) characterization techniques used on unirradiated and irradiated reactor pressure vessel steels yield large amounts of data. Machine learning techniques, including PCA, offer a novel method of analyzing and visualizing these large data sets in order to determine the effects of chemistry and irradiation conditions on the formation of radiation induced precipitates. In order to run analysis on these data sets, preprocessing must be carried out to convert the data to a usable format and mask the 2-D detector images to account for experimental variations. Once the data has been preprocessed, it can be organized and visualized using principal component analysis (PCA), multi-dimensional scaling, and k-means clustering. In conclusion, from these techniques, it is shown that sample chemistry has a notable effect on the formation of the radiation induced precipitates in reactor pressure vessel steels.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
High-power lithium-ion batteries are rapidly replacing the nickel metal hydride batteries currently used for energy storage in hybrid electric vehicles. Widespread commercialization of these batteries for vehicular applications is, however, limited by calendar-life performance, thermal abuse characteristics, and cost. The Advanced Technology Development Program was established by the U.S. Department of Energy to address these limitations. An important objective of this program was the development and application of diagnostic tools that provide unique ways to investigate the phenomena that limit lithium-ion cell life, performance, and safety characteristics. This report introduces a set of six Surface Science Spectra xray photoelectron spectroscopy (XPS) comparison records of data collected from positive electrodes (cathode) harvested from cylindrically wound, 18650-type, 1 A h capacity cells. The cathodes included in this study are (1) fresh, (2) following three formation cycles, (3) following calendar-life test for 12 weeks at 40 C, 60% state-of-charge (SOC), (4) following calendar-life test for 8 weeks at 50 C, 60% SOC, (5) following calendar-life test for 8 weeks at 60 C, 60% SOC, and (6) following calendar-life test for 2 weeks at 70 C, 60% SOC.
X-ray optics, desired for beamlines at free-electron-laser and diffraction-limited-storage-ring x-ray light sources, must have almost perfect surfaces, capable of delivering light to experiments without significant degradation of brightness and coherence. To accurately characterize such optics at an optical metrology lab, two basic types of surface slope profilometers are used: The long trace profilers (LTPs) and nanometer optical measuring (NOM) like angular deflectometers, based on electronic autocollimator (AC) ELCOMAT-3000. The inherent systematic errors of the instrument's optical sensors set the principle limit to their measuring performance. Where autocollimator of a NOM-like profiler may be calibrated at a unique dedicated facility, this is for a particular configuration of distance, aperture size, and angular range that does not always match the exact use in a scanning measurement with the profiler. Here we discuss the developed methodology, experimental set-up, and numerical methods of transferring the calibration of one reference AC to the scanning AC of the Optical Surface Measuring System (OSMS), recently brought to operation at the ALS Xray Optics Laboratory. We show that precision calibration of the OSMS performed in three steps, allows us to provide high confidence and accuracy low-spatial-frequency metrology and not â€print into' measurements the inherent systematic error of tool in use. Here, with the examples of the OSMS measurements with a state-of-The-Art x-ray aspherical mirror, available from one of the most advanced vendors of X-ray optics, we demonstrate the high efficacy of the developed calibration procedure. The results of our work are important for obtaining high reliability data, needed for sophisticated numerical simulations of beamline performance and optimization of beamline usage of the optics. This work was supported by the U. S. Department of Energy under contract number DE-AC02-05CH11231.
Purpose: Computed Tomography (CT) is a method to produce slice image of specific volume from the scanned x-ray projection images. The contrast of CT image is correlated with the attenuation coefficients of the x-ray in the object. The attenuation coefficient is strongly dependent on the x-ray energy and the effective charge of the material. The purpose of this presentation is to show the effective charge distribution predicted by CT images reconstructed with kilovoltage(kV) and megavoltage(MV) x-ray energy. Methods: The attenuation coefficients of x-ray can be characterized by cross section of photoionization and Compton scattering for the specific xray energy. In particular, the photoionization cross section is strongly correlated with the effective charge of the object. Hence we can calculate effective charge by solving the coupled equation between the attenuation coefficient and the theoretical cross section. For this study, we use the megavoltage (MV) and kilovoltage (kV) x-rays of Elekta Synergy as the dual source x-ray, and CT image of the Phantom Laboratory CatPhan is reconstructed by the filtered back projection (FBP) and iterative algorithm for cone-beam CT (CBCT). Results: We report attenuation coefficients of each component of the CatPhan specified by each x-ray source. Also the effective charge distribution is evaluated by the MV and kV dual x-ray sources. The predicted effective charges are comparable with the nominal ones. Conclusion: We developed the MV and kV dual-source CBCT reconstruction to yield the effective charge distribution. For more accuracy, it is critical to remove an effect of the scattering photon in the CBCT reconstruction algorithm. The finding will be fine reference of the effective charge of tissue and lead to the more realistic absorbed-dose calculation. This work was partly supported by the JSPS Core-to-Core Program(No. 23003), and this work was partly supported by JSPS KAKENHI 24234567.
Purpose: To investigate the proton induced X-ray emissions in gold-water mixture materials. Methods: In this study a Monte Carlo simulation was created using the GEANT4 toolkit (version 4.9.6). The geometry in this setup includes a 2 cm × 2 cm × 2 cm target, a scoring sphere (radius = 10 cm) and a 65 MeV planar proton source (2 cm × 2 cm). Four concentrations of a gold-water solution were irradiated with 5×10{sup 5} incident protons at a distance of 0.5 cm perpendicular to the surface of the target. The solutions of gold-water mixture had 10%, 5%, 1% and 0.5% of gold by mass, respectively. The number of photon emitting for the target was counted in the scoring sphere for the energy range of 0-86.0 keV in 0.1 keV bins. For this study the reference physics list PhysListEmStandard was used together with the x-ray fluorescence, Auger electron and PIXE (particle induced xray emission) options enabled. The range cuts for photons and electrons were set at 0.5 mm and 1.0 mm, respectively. Results: In the energy spectra of emitting X-ray fluorescence, peaks from gold K shell characteristic x-rays (68.8 and 66.9 keV) were observed. The number of counts under the peaks of Ka1 and Ka2 was found to increase with the increasing of the gold concentrations in the mixture materials. The X-ray yields (for both Ka1 and Ka2) when fitted with least-square method as a function of gold concentration demonstrate a linear dependency with R{sup 2} > 0.96. The Ka1yield per incident proton was found to be 0.0016 for 10% gold-water mixture solutions. Conclusion: This preliminary study with PIXE technique with gold nanoparticle has demonstrated potentials for its utilization in the development of range and dose verification methodology that is currently of great interest in the field of proton radiation therapy.