bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing an exact diffraction formula with gravitational wave source lensed by a supermassive black hole in binary systems
Authors: Guo Xiao , Cao Zhoujian 
Published: May 2024

Abstract
When it comes to long-wavelength gravitational waves (GWs), diffraction effect becomes
significant when these waves are lensed by celestial bodies. Typically, the traditional
diffraction integral formula neglects large-angle diffraction, which is often adequate for most of
cases. Nonetheless, there are specific scenarios, such as when a GW source is lensed by a
supermassive black hole in a binary system, where the lens and source are in close proximity,
where large-angle diffraction can play a crucial role. In our prior research, we have introduced
an exact, general diffraction integral formula that accounts for large-angle diffraction as
well. This paper explores the disparities between this exact diffraction formula and the
traditional, approximate one under various special conditions. Our findings indicate that, under
specific parameters — such as a lens-source distance of D
LS = 0.1 AU and a lens mass of
M
L = 4 × 106
M
⊙ — the amplification factor for the exact diffraction formula is
notably smaller than that of the approximate formula, differing by a factor of approximately
rF
≃ 0.806. This difference is substantial enough to be detectable. Furthermore, our study
reveals that the proportionality factor rF
gradually increases from 0.5 to 1 as D
LS
increases, and decreases as M
L increases. Significant differences between the exact and
approximate formulas are observable when D
LS ≲ 0.2 AU (assuming M
L
= 4 × 106
M
⊙) or when M
L ≳ 2 × 106
M
⊙ (assuming D
LS = 0.1 AU). These findings suggest that there is potential to validate our general
diffraction formula through future GW detections.
Fully non-Gaussian Scalar-Induced Gravitational Waves
Authors: Perna Gabriele , Testini Chiara , Ricciardone Angelo , Matarrese Sabino 
Published: May 2024

AbstractScalar-Induced Gravitational Waves (SIGWs) represent a particular class of primordial signals which are sourced at second-order in perturbation theory whenever a scalar fluctuation of the metric is present. They form a guaranteed Stochastic Gravitational Wave Background (SGWB) that, depending on the amplification of primordial scalar fluctuations, can be detected by GW detectors. The amplitude and the frequency shape of the scalar-induced SGWB can be influenced by the statistical properties of the scalar density perturbations. In this work we study the intuitive physics behind SIGWs and we analyze the imprints of local non-Gaussianity of the primordial curvature perturbation on the GW spectrum. We consider all the relevant non-Gaussian contributions up to fifth-order in the scalar seeds without any hierarchy, and we derive the related GW energy density ΩGW(f). We perform a Fisher matrix analysis to understand to which accuracy non-Gaussianity can be constrained with the LISA detector, which will be sensitive in the milli-Hertz frequency band. We find that LISA, neglecting the impact of astrophysical foregrounds, will be able to measure the amplitude, the width and the peak of the spectrum with an accuracy up to 𝒪(10-4), while non-Gaussianity can be measured up to 𝒪(10-3). Finally, we discuss the implications of our non-Gaussianity expansion on the fraction of Primordial Black Holes.
Possibility and stabilizing effect of Mo clusters in the Ni-based single-crystal superalloy
Authors: Du Yiqun , Jin Huixin , Kang Rongkai , Zhang Boya , Wang Han , Zhang Jianxin 
Published: May 2024

Abstract
Nickel-based single-crystal superalloys are crucial materials for the preparation of aero-engine turbine blades. Many solute elements are added to superalloys for strengthening. However, the relationship between the clustering behavior of solute atoms and the properties of nickel-based single-crystal superalloys is still unclear. Herein, we conduct first-principles calculations on γ phases with Mo−Mo and Mo−Mo−Ru clusters to reveal the possibility and stabilizing mechanism of solute clusters. Introducing Mo lowers the total energy, binding energy, and formation energy of the γ phase due to the replacement of weak Ni−Ni interaction with strong Mo−Ni bonding. Note that the γ phase containing the Mo−Mo cluster is more stable than that containing a Mo single atom, possibly owing to a wide affecting range. The Ru atom added to the γ phase can further boost system stability, and it tends to form a Mo−Mo−Ru cluster. The stabilizing impact of the Mo−Mo−Ru cluster is demonstrated to be the replacement of weak Ni−Mo interaction by the strong Ru−Mo interaction, which may be derived from the enhanced d-orbital hybridization.
All-electron basis sets for H to Xe specific for ZORA calculations: Applications in atoms and molecules
Authors: Gomes C. S. , Jorge F. E. , Canal Neto A. 
Published: May 2024

Abstract
A segmented basis set of quadruple zeta valence quality plus polarization functions (QZP) for H through Xe was developed to be used in conjunction with the ZORA Hamiltonian. This set was augmented with diffuse functions to describe electrons farther away from the nuclei adequately. Using the ZORA-CCSD(T)/QZP-ZORA theoretical model, atomic ionization energies and bond lengths, harmonic vibrational frequencies, and atomization energies of some molecules were calculated. The addition of core-valence corrections has been shown to improve the agreement between theoretical and experimental results for molecular properties. For atomization energies, a similar observation emerges when considering spin-orbit couplings. With the augmented QZP-ZORA set, static mean dipole polarizabilities of a set of atoms were calculated and compared with previously published recommended and experimental values. Performance evaluations of the ZORA and Douglas–Kroll–Hess Hamiltonians were made for each property studied.
Unit one is intrusive
Authors: Flater David 
Published: May 2024

Abstract
The SI brochure’s treatment of quantities that it regards as dimensionless, with the associated unit one, requires certain physical quantities to be regarded as simply numbers. The resulting formal system erases the nature of these quantities and excludes them from important benefits that quantity calculus provides over numerical value calculations, namely, that accidental confusion of different units and different kinds of quantities is sometimes prevented. I propose a better treatment that entails removing from the SI brochure those prescriptions that conflict with common practices in the treatment of dimensionless quantities, especially the definition and use of non-SI dimensionless units that are distinguished by kind.
Innovative Cesiation Deriving Incredible 145 mA Beam from J-PARC Cesiated RF-Driven H− Ion Source
Authors: Ueno A 
Published: May 2024

Abstract
In NIBS2022, the stable 8 hours operation of the J-PARC cesiated RF-driven H− ion source (IS) in a test-stand with a 69.9 keV 120 mA beam and a beam duty factor of 4 % (1 ms x 40 Hz) was reported. However, the Cesiation condition was produced after many times and rather large amount of Cs and H2Os injections. The fluctuation of the H− ion beam intensity (IH
−) in a pulse and the transverse emittances were rather larger than those for the previous 65 keV 110 mA operation. The plasma electrode temperature (TPE) of 254 °C much higher than that not only for the usual J-PARC IS (about 70 °C) but also for the standard cesiated H− ion sources (180 ∼ 200 °C) suggested the existence of novel H2O mediated cesiation surviving against the high TPE. In this paper, the J-PARC IS improvements based upon a hypothesis of the best cesiation constituted of sub monolayer H2O (chemically bound with Mo) mediated cesiation and Cs half monolayer on remaining surface are presented. The innovative cesiation derived a 76.5 keV 145 mA beam stably with the small beam fluctuation and transverse emittances suitable for Radio Frequency Quadrupole LINACs of high energy LINACs. The measured results of the 145 mA / 83 mA beam, extraction electrode current and RF waveforms, parameter trends of an 8 hours 145 mA operation and the transverse emittances are presented. The optimum TPE was increased from 70 °C to 230 °C. Furthermore, the beam intensity for the J-PARC IS operation energy of 52.5 keV was increased from 72 mA to 83 mA, which was consistent with the 1.5 power perveance law on the beam energy compared with 145 mA for 76.5 keV.
Investigation of plasma chamber erosion in an RF ion source
Authors: George A , Melanson S , Dehnel M , Hoehr C 
Published: May 2024

Abstract
Filament driven plasma sources are widely used to produce ion beams, but they require frequent maintenance due to the limited filament lifetime. External radio-frequency (RF) coupled ion source offers a filament-free plasma and hence better maintenance. However, one of the issues encountered during the development of a planar external RF-powered ion source at D-Pace was the erosion of its copper plasma chamber and subsequent formation of copper deposits on the Aluminum Nitride (AlN) RF window. The copper deposits on the RF window deteriorate the power coupling between the external antenna and the plasma. This paper investigates the erosion of the plasma chamber and describes some of the methods used to control the deposition of copper on the RF window.
Roadmap for the increase of beam brilliance from ECRIS and Microwave Discharge Ion Sources
Authors: Neri Lorenzo , Bilotta G , Boscarino S , Castro G , Celona L , Coco A , Comunian M , Grespan F , Leonardi O , Miraglia A , Russo G , Sorbello G , Gammino S 
Published: May 2024

Abstract
The requirements for future accelerator chains need to increase the injected beam brilliance significantly, still keeping high the beam quality in terms of reliability, reproducibility and stability. A roadmap for ion source development may consist of several steps: plasma simulation, multiphysics simulation of each system component, high-level control system, plasma characterization, beam characterization, data analysis and, again, plasma simulation. The cycle starts and ends with plasma simulation because it is the instrument that shows how different phenomena take part in the plasma and beam formation and because, in such a way, the accuracy grows with each cycle. Commercial multiphysics simulation tools are essential for adequately designing all ion source equipment: magnets, intense electrostatic field regions, microwave propagation and coupling, thermal dissipation and vacuum. The dependence of source performances from source parameters (magnetic field profile, gas pressure, microwave power) has been widely investigated using a high-level control system[1] able to test tens of thousands of source configurations without human interaction. This characterization technique allowed us to identify a new magnetic configuration, High Stability Microwave Discharge Ion Sources[2], that produces a beam with high stability, intensity and brilliance. The plasma simulation tool we developed discloses the role of two types of electrostatic waves in plasma formation and their correlation to stability. The simulation provides a complete view of ions and electrons energy and density distributions, the formation of the plasma meniscus and the beam extraction. The paper will present the results obtained with this development procedure on Microwave Discharge Ion Sources and how we started to apply it to the Electron Cyclotron Resonance Ion Sources development.
Beam divergence of RF negative hydrogen ion sources for fusion
Authors: Wimmer C. , Barnes M. , den Harder N. , Navarro A. , Nocentini R. , Orozco G. , Wünderlich D. , Heinemann B. , Fantz U. , Serianni G. , Veltri P. 
Published: May 2024

Abstract
Neutral beam injectors (NBI) for fusion facilities have strict requirements on the beam divergence (7 mrad for the ITER NBI at 1 MeV). Measurements of the single beamlet divergence of RF negative ion sources (at lower beam energy < 100 keV) show significantly higher values (9–15 mrad), also larger than filament arc sources at similar beam energies. This opened up questions whether the higher divergence is caused by different measurement or evaluation techniques, whether it is a direct cause of the RF source, e.g. due to a higher temperature of negative ions or an oscillating extraction meniscus, and whether it is a problem at all after full acceleration. In a joint effort between the labs modeling and diagnostic capabilities at the NNBI test facilities have been strongly extended and evaluation methods benchmarked. Particularly challenging is the strong increase in beamlet divergence at a lower filling pressure, seen both in filament arc and RF sources.
Beside the source and beam investigations carried out in SPIDER (with selected, isolated apertures rather than the total of 1280 apertures) at Consorzio RFX, the IPP test facilities ELISE (640 apertures) and BATMAN Upgrade (70 apertures) contribute to the physics understanding of the beam optics in RF sources. The determination of the beam divergence is not straight-forward because effects originating from measuring the divergence of multiple beamlets (Beam Emission Spectroscopy) and/or constraints from the individual diagnostic (lateral heat conductance in CFC tiles) lead to difficulties. Still, the divergence requirement is not met at the limited total beam energy available at ELISE and BATMAN Upgrade (< 60kV). However, variation of the beam energy show a decrease of the divergence for higher energies and beam simulation for the ITER NBI accelerator predict that the divergence requirement will be met after full acceleration of the negative ion beam.
Development of air-cooled plasma grid system for long-pulse negative ion beam acceleration with ITER-relevant perveance
Authors: Kisaki M. , Tanaka Y. , Suzuki K. , Hiratsuka J. , Murayama M. , Ichikawa M. , Tobari H. , Kashiwagi M. 
Published: May 2024

Abstract
Long pulse beam experiment has been carried out with a multi-aperture and five-stage accelerator with the same gap length, the same aperture interval, and the same aperture diameter as ITER accelerator in order to demonstrate ITER-relevant beam of 230 Am−2 and 870 keV. An actively cooled plasma grid (PG) with compressed air has been newly developed to maintain the PG temperature within suitable range for surface production of hydrogen negative ion (H–) and to realize the stable H– production. It is confirmed that the air-cooled PG has a capability to control the PG temperature within target range for 300 s with feedback control of the air flow rate. The stable beam acceleration with ITER relevant perveance has been successfully achieved for 300 s at 275 keV with PG cooling, 100 s at 500 keV, and 10 s at 750 keV without PG cooling.
Producing intense uranium ion beam for RIKEN RI beam factory
Authors: Higurashi Y , Saquilayan G Q , Ohnishi J , Haba H , Nagatomo T 
Published: May 2024

Abstract
Intense highly charged uranium (U) ion beams were produced using RIKEN 28 GHz superconducting electron cyclotron resonance (ECR) ion source in a high-temperature oven (HTO). We used a double-oven system to ensure ample vapor supply. Moreover, we optimized the vapor delivery into the plasma at a constant microwave power input. Consequently, we achieved intense U-ion beams, specifically 250 eμA for U35+, 36 eμA for U46+, and 10 eμA for U54+, at an injected microwave power of approximately 3000 W. This achievement stems from recent advancements, notably the optimization of the material consumption rates aimed at maximizing beam intensity, which we briefly review here.
For intense proton beam production with compact ion sources: the ALISES ion source family developed at CEA Saclay
Authors: Tuske O , Delferriere O , Dubois A , Gauthier Y , Harrault F , Sauce Y , Thibeau T 
Published: May 2024

Abstract
The production of intense proton beams in CEA Saclay started in the 90’s with the development of the SILHI source to inject the IPHI accelerator. This ECR ion source is still in operation nowadays. ECR plasma is a well-known heating process and plasma chamber internal dimensions were investigated in order to reduce size and maintenance time. In 2012 R&D investigations on those simple plasma chamber parameters were started with the design of the first ALISES ion source that will give birth to a new source family still in progress today. This paper will summarize the different steps of this development.
First ion source at ISOL@MYRRHA with an improved thermal profile - Theoretical considerations
Authors: Hurier S , Rijpstra K , Ramos J P , Popescu L , Cocolios T E , Mancheva R , Chrysalidis K , Rothe S , Au M , Koliatos A 
Published: May 2024

Abstract
ISOL@MYRRHA will be a new Radioactive Ion Beam (RIB) facility in Belgium based on the Isotope Separation On-Line (ISOL) technique, and established within the framework of MYRRHA, the world’s first large-scale accelerator driven system project at power levels scalable to industrial systems. The surface ion source, or hot cavity, is chosen as initial source for its reliability and simple design. To account for the higher flux of atoms through this cavity, a theoretical study of the processes within the ion source is discussed here, based on theoretical equations and thermal-electric simulations. In the past, the temperature was clearly identified as a key element to this source, but with the assumption that it remains constant throughout the cavity. Nonetheless, more recent thermal-electric simulations have revealed that the source Ohmic heating leads to temperature gradients along the cavity tube. The temperature profile impact on ionisation in the hot cavity will be reviewed here.
New Technique of Injecting Radioactive Ions into Charge Breeding ECR Ion Source
Authors: Tabacaru G , Ärje J , Kolhinen V , Roeder B , Kim G , May D , Clark H 
Published: May 2024

Abstract
Cyclotron Institute at Texas A&M University started a project to develop the reacceleration of radioactive ions using the two operational cyclotrons and a Charge Breeding ECR ion source. The radioactive ions are produced primarily via (p,n) reactions using the IGISOL technique. The reaction products are transported into a Charge Breeder ECR ion source where their charge state is boosted from 1+ to higher charge states. The transport of the radioactive products and the injection into the ion source are very important for the efficiency of charge breeding. Two techniques have been used: acceleration–deceleration method (classic) and low - energy RF-only sextupole ion guide transport and injection method (innovative technique). The last method appears to be very efficient and great charge breeding efficiency was observed. The presentation of the entire project, the new injection technique, experimental results, and future plans will be discussed.
Pulse-stretching out of the CANREB EBIS
Authors: Cavenaile M. , Charles C.R.J. , Kester O. , Schultz B.E. , Ames F. , Kanungo R. 
Published: May 2024

Abstract
The CANadian Rare isotope facility with Electron-Beam ion source (CANREB) at TRIUMF is set to deliver rare isotope beams in high charge states. In the Electron Beam Ion Source (EBIS) ions are charge-bred by collisions with an electron beam of up to 500 mA. A strong magnetic field (up to 6T) maximizes the overlap between ions and electron beam and increases the breeding efficiency. Ion confinement is maintained by a combination of an electrostatic field and the electron beam space-charge potential. Ions are released by lowering the trapping potential with a step function. The system is operated at a pulse repetition frequency up to 100 Hz. Due to the short trap length, this fast extraction scheme produces pulses shorter than 10 µs with high instantaneous rates that can saturate detectors in experiments. Stretching the pulse can be done using a slowly varying voltage function to modify trap electrode potentials instead of a step function. The ideal function produces a pulse with a flat top distribution and can be calculated by knowing the ion energy distribution inside the trap. The latest pulse-stretching results will be discussed including the latest pulse duration up to 1.4 ms that have been produced. The slow extraction scheme has also been used for a measurement of the effective energy distribution of the ions inside the trap.
Production of negative ion beams through charge transfer between negative hydrogen ion beams and non-metallic gases
Authors: Paul A , Melanson S , Junginger T , Dehnel M 
Published: May 2024

Abstract
Negative ion beam applications in tandem accelerators are used for nuclear research, environmental studies, materials analysis, medical treatments, and ion implantation in semiconductor devices. Conventional methods for generating negative ions for tandem accelerators rely on metallic vapors (typically alkali) for charge exchange, which pose challenges like contamination, electrical shorting and breakdowns, and maintenance issues. To address these drawbacks, this work explores an alternative approach to produce negative ions using a non-metallic charge exchange process. It involves directing negative hydrogen ions into neutral gases within a specially designed charge exchange cell equipped with an electrostatic accelerator. The method is applied to various gas targets, including He, H2 and O2, to accelerate and measure resulting negative ions. This innovative approach aims to mitigate contamination concerns associated with metallic vapor double-charge exchange methods and explore novel avenues for negative ion production through charge transfer. Any newly formed negative ion beam current conversion ratios from the incident H− beam will be reported as progress in this research.
A protype of compact and high-yield DD neutron generator
Authors: Chen L H , Cui B Q , Ma R G , Tang B , Ma Y J , Zhang Y F , Ma X , Lee W , Wang Y F 
Published: May 2024

Abstract
Neutron generators are widely utilized in various fields, including scientific research, activation analysis, and detection of IED or drugs, due to their high neutron yield, safety, and flexibility. In this paper, we report about the development of a compact and high-yield dd neutron generator based on an Electron Cyclotron Resonance (ECR) ion source at the China Institute of Atomic Energy. The ion source to produce a high-intensity ion beam, which is used to bombard a water-cooled solid metal target. By means of the (D, D) nuclear reaction, 2.5MeV neutrons are generated. We describe the detailed design of this compact dd neutron generator and present the preliminary measurement results of its neutron yield, as measured by a calibrated 3He neutron detector. The generator has been tested for nearly 300 hours, demonstrating stable operation without any component damage. With its compact size, high yield, and long lifespan, this generator could meet the demand for a 2.5MeV neutron source in many scientific research and select industrial applications.
Numerical study of gas-solid two-phase flow in the snout of continuous hot-dip galvanizing process
Authors: Sun Chuhao , Lin Ying , Cao Jiayong , Tang Chenglong , Wang Xuemin 
Published: May 2024

Abstract
In the hot-dip galvanizing process for strip steel, zinc vapor oxidizes and forms zinc ash in the snout. Given that the snout connects the annealing furnace, the zinc ash will return to the annealing furnace with the gas, affecting the upstream process. The gas-solid two-phase flow regularity in the snout is the key issue for zinc ash control. In this paper, the snout of a hot-dip galvanizing production line was taken as the physical model. The two-phase flow was simulated by the Euler-Lagrange method and the zinc ash particles were simulated via the discrete phase model (DPM). The results show that several vortex regions exist in the snout due to the forced convection caused by the moving strip and changes in flow channel sizes. There exist differences in the movement of zinc ash with different diameters. Small zinc ash has a strong tracking performance with the gas. Large zinc ash is easy to remain in the snout. In addition, orthogonal analysis was conducted to determine the optimal parameter combination. The research results provide theoretical guidance for the operation scheme of the gas circulation system.