bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural convection and heat transmission of two-phase Bingham Fe3O4-CoFe2O4-water hybrid nanofluid flow in an enclosure with a corrugated heated cylinder
Authors: Mahmud Muhammad Zawad , Molla Md Mamun 
Published: May 2024

Abstract
The Galerkin weighted residual finite element method (GFEM) has been used to numerically investigate the natural convection flow of two-phase Bingham hybrid nanofluid in a square cavity with a corrugated cylinder at the center. The base fluid here is water. The hybrid nanofluid is made of Fe3O4-CoFe2O4 nanoparticles. The flow inside the enclosure is considered laminar, non-Newtonian, and incompressible. The corrugated cylinder is taken heated. The top and bottom walls of the outer square are considered adiabatic, and the left and right walls are considered cold. Several non-dimensional parameters, including the Rayleigh number (Ra = 104, 105, 106), the Bingham number (Bn = 0, 0.5, 1), the volume fraction (ϕ = 0.00, 0.04), the Brownian parameter (Nb = 0.1, 0.2, 0.3), thermophoresis parameter (Nt = 0.1, 0.2, 0.3), buoyancy ratio (Nr = 0.1, 0.2, 0.3), corrugation (N = 5, 6, 7), the Prandtl number (Pr = 6.2), and the Lewis number (Le = 1000) have been numerically simulated. The main focus of this work is to witness streamlines, isotherm, and nanoparticles’ volume fraction distribution and understand heat transmission with the help of average Nusselt number and local Nusselt number for several parameters for a two-phase Bingham hybrid nanofluid. The results show that an upsurge in Ra increases the extent of the upper two vortices and decreases the extent of the lower two vortices. All four vortices are seen to increase in dimension for an increase in Bn. The same observation is found for an increase in ϕ. The lower vortices are growing, and the top ones are nearly eliminated for base fluid, while those are visible for nanofluid when corrugation is increased. A further expansion completely destroyed the higher ones and increased the size of the bottom ones. The average Nusselt number (

Nu

¯

) increases when Ra is incremented.

Nu

¯

rises with a rise in ϕ. An increment in ϕ to 0.04 results in a 4.43% gain in

Nu

¯

. An increase in Bn is causing

Nu

¯

to drop by 18.02%. For Ra = 105 and Bn = 2, ϕ = 0.02 has the maximum heat transfer enhancement between 0.00 ≤ ϕ ≤ 0.04. In the future, we plan to use mixed convection in a three-dimensional domain along with the impact of magnetohydrodynamics (MHD).
A modified Astable multi-vibrator-driven 3D chaotic circuit with Dual LC band stop filters
Authors: Ponnambalam Maran , Ponnambalam Mathivanan 
Published: May 2024

Abstract
This work describes a proposed circuit design with three essential parts: an Astable Multi-vibrator (ASMV) source producing a square wave as the driving signal, a two-stage LC band stop filter selectively attenuating frequencies with a focus on suppressing high-frequency components, and an integrator combining outputs from the second and third stages. Using two extra feedback channels, a standard ASMV gains the ability to change the duty cycle of the square wave, effectively altering the amplitude and duty cycle of the ASMV output signal. The LC band stop filter is vital for reducing or blocking frequencies close to 650 Hz and allowing other frequencies to predominate in the signal. The output frequency of the proposed circuit is governed by its specific parameters and frequency response characteristics. The suggested three-dimensional chaotic circuit produces dynamic, complex chaotic attractors with a simple circuit complexity. The differential equations describing the circuit’s functioning were checked using MATLAB. Circuit working was verified using Keysight ADS simulation and validated by experimental measurement. The randomness of the state variables are verified using the NIST test.
Search for heavy dark matter from dwarf spheroidal galaxies: leveraging cascades and subhalo models
Authors: Song Deheng , Hiroshima Nagisa , Murase Kohta 
Published: May 2024

Abstract
The Fermi Large Area Telescope (Fermi-LAT) has been widely used to search for
Weakly Interacting Massive Particle (WIMP) dark matter signals due to its unparalleled sensitivity
in the GeV energy band. The leading constraints for WIMP by Fermi-LAT are obtained from the
analyses of dwarf spheroidal galaxies within the Local Group, which are compelling targets for
dark matter searches due to their relatively low astrophysical backgrounds and high dark matter
content. In the meantime, the search for heavy dark matter with masses above TeV remains a
compelling and relatively unexplored frontier. In this study, we utilize 14-year Fermi-LAT
data to search for dark matter annihilation and decay signals in 8 classical dwarf spheroidal
galaxies within the Local Group. We consider secondary emission caused by electromagnetic cascades
of prompt gamma rays and electrons/positrons from dark matter, which enables us to extend the
search with Fermi-LAT to heavier dark matter cases. We also update the dark matter subhalo
model with informative priors respecting the fact that they reside in subhalos of our Milky Way
halo aiming to enhance the robustness of our results. We place constraints on dark matter
annihilation cross section and decay lifetime for dark matter masses ranging from 103 GeV to
1011 GeV, where our limits are more stringent than those obtained by many other high-energy
gamma-ray instruments.
Direct Detection and Characterization of Exoplanets Using Imaging Fourier Transform Spectroscopy
Authors: Zhang 张 Jingwen 婧雯 , Bottom Michael , Serabyn Eugene 
Published: May 2024

Abstract
Space-based direct imaging provides prospects for detection and spectral characterization of exoplanets at optical and near-infrared wavelengths. Integral field spectrographs (IFS) have been historically baselined for these mission concepts. However, multiple studies have revealed that detector noise is a serious obstacle for such instruments when observing extremely faint targets such as Earth-like planets. Imaging Fourier transform spectrographs (iFTS) are generally less sensitive to detector noise, and have several other compelling features such as simultaneous imaging and spectroscopy, smaller-format detector requirements, and variable spectral resolving power. To date, they have not been studied as options for such missions. Here, we compare the capabilities of IFS and iFTS for directly obtaining spectra from an Earth-like planet using both analytic and numerical models. Specifically, we compare the required exposure times to achieve the same signal-to-noise ratio with the two architectures over a range of detector and optical system parameters. We find that for a 6 m telescope, an IFS outperforms an iFTS at optical wavelengths due to the effects of distributed photon noise. In the near-IR, the relative efficiency of an IFS and iFTS depends critically on the instrument design and detector noise. An iFTS will be more efficient than an IFS if the readout noise of the near-IR detector is above ∼2–3 e− pix−1 frame−1 (t
frm = 1000 s), which correspond to half to one-third of the state-of-art detector noise. However, if the readout noise is reduced below this threshold, the performance of an IFS will experience a substantial improvement and become more efficient. These results motivate consideration of an iFTS as an alternative option for future direct imaging space missions in the near-IR.
Developing a penning ionization gauge ion source with a filament for a compact ion microbeam system
Authors: Ishii Yasuyuki , Ohkubo Takeru , Saito Yuichi 
Published: May 2024

Abstract
We present the development of a penning ionization gauge ion source with a filament (F-PIG) for producing submicron ion beams in a compact ion microbeam system. The conventional penning ionization gauge ion source (PIG) represents a viable choice for microbeam system due to its compact size and low power consumption. However, directly utilizing a PIG for generating submicron ion beam poses challenges, primarily from significant energy spread, causing substantial aberrations. Considering this, this study proposes a solving the generation of low-voltage discharge plasma, achieved using low-energy electrons from a filament by focusing on the development of F-PIG for this purpose. Experimental results demonstrate that the F-PIG exhibits considerable promise an ion source to forming submicron beam within a compact ion microbeams system. These findings indicate that F-PIG can effectively reduce the width of the beam energy spread, making it a valuable asset for microbeam applications.
In situ effective pumping speed measurements as a tool for non-evaporable getter activation and saturation monitoring
Authors: Kondrashev S. , Beebe E. , Coe B. , Rodowicz T. 
Published: May 2024

Abstract
We have developed method of in situ effective pumping speed measurements based on injecting finite gas pulse into a vacuum volume and subsequent recording of pressure response using a Residual Gas Analyzer (RGA). The pressure burst caused by injected gas pulse falls exponentially in time and the exponential coefficient of such pressure decay is proportional to total effective pumping speed of all vacuum pumps acting on vacuum chamber volume. The effective pumping speed can be extracted from the dependence of injected gas species pressure vs time recorded by an RGA. Non-Evaporable Getters (NEGs) are widely used in multiple ultra and extremely high vacuum devices and applications during the last several decades. Areas of NEG applications were recently expanded into vacuum devices with relatively high-pressure levels (up to 10−7 Torr) by the invention of high capacity ZAO NEG which can be operated at elevated temperatures. The intrinsic property of all NEG-based vacuum pumps is the reduction of their pumping speed, called “NEG saturation”, after an extended period of operation. Typical time interval for such process can span from about a month and up to a few years depending on NEG type, vacuum level of NEG pump operation, and residual gas content. After that, the NEG pump will require a re-activation cycle to restore its pumping speed close to the initial value. For many applications it is difficult to realize what is the current pumping speed of NEG pump is and when the pump should be re-activated. A method for in situ effective pumping speed measurements developed in this study can be used as a tool for NEG-based pump activation and saturation monitoring. Application of such an approach to monitor pumping status of NEG pumps was utilized and will be continually used at Extended EBIS which was recently developed and commissioned for Relativistic Heavy Ion Collider (RHIC) and future Electron Ion Collider (EIC). The results obtained during commissioning are presented and discussed.
A Long-life Laser Ion Source Using a Reproducible Solidified Gas Target
Authors: Hasegawa J , Inoue Y , Matsubara N , Tamura J , Takahashi K , Horioka K , Takayama K 
Published: May 2024

Abstract
A novel laser ion source using a reproducible cryogenic target has been developed for next-generation heavy-ion cancer therapy accelerators. A solid thin layer of butane formed on a cylindrical cold head cooled with liquid nitrogen is ablated by a frequency-doubled Nd:YAG laser to generate high-charged carbon ions. The properties and reproducibility of the carbon plasmas produced under various conditions are investigated.
H− Ion Source RF Plasma Testing with 13 MHz and 27 MHz at the Spallation Neutron Source (SNS)1
Authors: Narayan A.H. , Piller C. , Vestal D.C. , Stinson C. , Han B. , Welton R. , Terszakowec G. , Andzulis V. , Kang Y. 
Published: May 2024

Abstract
The baseline RF-driven H− ion source configuration at the Spallation Neutron Source (SNS) facility uses a continuous wave (CW) 600 W 13 MHz RF system to ignite and maintain a low-density plasma inside the ion source vacuum chamber. After the continuous low-density 13 MHz plasma has been established, a pulsed (typical 1 ms pulse width and 60 Hz pulse repetition rate) 80 kW 2 MHz RF system is used to increase the plasma density to produce the pulsed H− ion beam. Incremental upgrades and improvements to the SNS ion source systems have resulted in the ability to reliably operate an H− ion source for SNS neutron production run cycles that can last up to four months. Conditions inside the SNS H− ion source evolve throughout a four-month run cycle due to changes in impurity levels, sputtering, and erosion. As the internal ion source conditions change during the run cycle, there can also be changes in plasma stability and the 13 MHz RF power level required to ignite the plasma. This paper presents the preliminary results of testing performed on the SNS Ion Source Test Stand (ISTS) system where we looked at plasma ignition and plasma stability using 27 MHz RF in place of the baseline 13 MHz RF system.
Design and preliminary tests of an Active Plasma Chamber for ECR Ion Sources
Authors: Odorici F. , Castro G. , Leonardi O. , Russo F. , Malferrari L. , Celona L. , D’Agostino G. , Gammino S. , Chines F. , Costanzo G. , Furini M. , Gessi C. , Guerzoni M. , Margotti A. , Michinelli R. , Siliato D. 
Published: May 2024

Abstract
An innovative plasma chamber for Electron Cyclotron Resonance Ion Sources (ECRIS) has been developed at INFN and will soon be installed and tested with the AISHa (Advanced Ion Source for Hadrontherapy) ion source. It consists in inserting a particular liner into the existing chamber, which allows an electrical segmentation of the internal walls of the chamber. The purpose of this system is to reduce the ion losses induced by the anisotropic diffusion mechanism, to improve the plasma confinement and thus to increase the overall performance of the ion source. In fact, in ECRIS plasmas, electrons mostly diffuse along magnetic field lines while ions mostly leak across the same lines. In particular, the inner walls of the plasma chamber are covered with 30 tiles, each one polarized to a proper positive voltage. The tiles are made of Al-6082 and anodized except for the surface directly facing the plasma. The anodizing process makes each tile electrically insulated from the others and from the plasma chamber while preserving the correct operation of the cooling system. The tiles are wrapped by 2 half-cylinders made of Al-6082 acting as shells. Some tiles are equipped of a temperature sensor and machined to allow the wiring of the entire system.
In this work the results of the preliminary tests of the thermal and electrical behaviour of the active chamber and the future perspectives are presented.
Dynamic Change of the Work Function of Plasma Electrode Materials due to Hydrogen Plasma exposure
Authors: Sasao Mamiko , Broude Juan-Pablo , Cartry Gilles , Layet Jean-Marc , Nakano Haruhisa , Nishiwaki Mayuko , Wada Motoi 
Published: May 2024

Abstract
It has been known that the work function of plasma electrode (PE) surfaces such as Cs-covered Mo and C12A7-electride can be decreased when the surfaces are immersed in hydrogen (or deuterium) plasma. We discovered that the work function of the C12A7-electride changed right after the termination of plasma exposure with the time constant of a few minutes. This phenomenon was not observed on the surface of clean metals (Mo or Ta). By extrapolating the dependence of work function against time to determine the value at the plasma termination, the work function during plasma exposure was estimated to be 2.4 – 2.5 eV, which can be compared with the value of the electride exhibiting metallic conductivity.
Recent advancements with the H− injector performance for the Spallation Neutron Source operation and upgrade
Authors: Han Baoxi , Welton Robert , Stinson Chris , Andzulis Vic , Terszakowec Greg , Piller Chip , Narayan Amith , Peplov Vladimir , Pennisi Terry , Murray Syd , Stockli Martin , Kim Sang-Ho 
Published: May 2024

Abstract
The Spallation Neutron Source (SNS) located at the Oak Ridge National Laboratory is an accelerator-based, pulsed neutron facility utilized for a broad range of scientific research and industrial applications. In the past 5 years, the facility has reliably been operated at its baseline design beam power of 1.4 MW, and it is currently undertaking an upgrade to double its power to 2.8 MW. A 65-keV H− injector, which comprises an rf-driven H− ion source and an electrostatic low energy beam transport, delivers the required high-current, time-structured H− beam to the accelerator. The H− injector can reliably provide 50-60 mA beam current at 6% duty-factor (1 ms, 60 Hz) for a 3-4 month service cycle. To ensure sufficient operational margins for the SNS routine operations and ongoing upgrade requirements, the injector system has been continuously improved on a R&D test stand. This paper presents the operational status and recent advancements with the injector system performance including the enhanced ion source beam output capability up to ∼110 mA, the improved ion source plasma ignition reliability using a 27.12-MHz RF system, and the upgraded LEBT beam chopper system etc.
RF-driven H− sources of long life-time and new LEBT developed at CSNS
Authors: Chen Weidong , Li Hui , Liao Hui , Lü Yongjia , Cao Xiuxia , Liu Shengjin , Xiao Yongchuan , Chen Benzheng 
Published: May 2024

Abstract
An RF-driven ion source has been put into commissioning on the China Spallation Neutron Source (CSNS) accelerator since September 2021. In the last two run cycles, the ion source has operated for 310 and 323 days respectively, with an availability of almost 100%. To fully meet the requirements of the CSNS project Phase-II (CSNS-II), the beam intensity from the linac should be enhanced to above 40mA, and the transverse emittance should be minimized to suppress beam loss during acceleration and transportation. A new test bench consisting of an ion source and a LEBT has been constructed to carry out these optimization and research. The featured functions of the LEBT are associated with proton elimination and electrostatic beam chopping. This report covers the operation status and development of the RF-driven H− source and the new LEBT.
Creation and characterisation of multi-charged cerium beams at TRIUMF’s OLIS
Authors: Justus P. , Charles C. R. J. , Ames F. , Jayamanna K. , Malbrunot-Ettenauer S. 
Published: May 2024

Abstract
A novel 140Ce
n+ stable ion beam was developed at TRIUMF’s Off-Line Ion Source (OLIS) facility for fundamental research into (i) astrophysical processes, and (ii) forming lanthanide molecules with O2 gas and halogens. This first creation of a multi-charged 140Ce beam at OLIS is a successful chemical analog for actinide beams and molecule formation at TRIUMF’s TITAN facility for future electron dipole moment (EDM) measurements with rare radioactive thorium molecules.
The High Beam to Power Efficiency Investigation of Miniaturized Microwave Ion Source
Authors: Peng Shixiang , Ma Tenghao , Cui Bujian , Wu Wenbin , Jiang Yaoxiang , Guo Zhiyu , Chen Jiae 
Published: May 2024

Abstract
A miniaturized 2.45 GHz microwave ion source (MIS) with plasma chamber of ϕ30 mm × 40 mm that has the ability to produce more than 20 mA CW hydrogen ion beam with 180 W microwave power has been built at Peking University (PKU) 5 years ago1. A hibrid discharge principle has been proposed on this kind of MIS2. Recently, under the structure of this MIS, factors such as input power, pressure, magnetic field configuration and the size of plasma chamber have been investigated. Based on this research, a more compact 2.45 GHz microwave ion source with inner diameter of 24 mm has been developed. A 32.5 mA hydrogen ion beam was obtained with only 100 W microwave power.
The SPES Laser Ion Source: Time Structure and Laser Enhancement Measurements with Sm+ beam
Authors: Khwairakpam O S , Mancheva R , Au M , Bernerd C , Centofante L , Chrysalidis K , Crepieux B , Fedosseev V N , Heinke R , Marchi T , Mariotti E , Marsh B A , Monetti A , Nicolosi P , Rothe S , Scarpa D , Schuett M , Stora T , Andrighetto A , Manzolaro M 
Published: May 2024

Abstract
A two-step resonance photo-ionization scheme has been used to ionize samarium atoms in the SPES tantalum hot-cavity ion source. The effect of the ion load on the ion beam time structure and the laser enhancement of the ion yield has been studied at different ion source temperatures. Generally, the introduction of more positive ions (ion load) affects negatively the overall confinement of the laser ions inside the volume of the ion source. Possible enhancement of the laser ion confinement through the introduction of neutrals is observed as well. The ion load is also observed to affect the confinement in the transfer line much more than in the hot cavity. Measurement of the time structure with inverted polarity of the cavity DC heating supply confirmed the significance of the longitudinal potential for ion extraction. The laser enhancements of the ion yield are found to be sensitive to the ion load at low operating temperature of the ion source i.e. 1800°C, whereas at 2050°C and 2200°C, they are relatively stable till an ion load value of 1.2 µA.
A new proton injector based on PKU-type 2.45GHz PMECR ion source for BNCT facility
Authors: Cui Bujian , Peng Shixiang , Ma Tenghao , Wu Wenbin , Jiang Yaoxiang , Guo Zhiyu , Chen Jiaer 
Published: May 2024

Abstract
A first fully domestically Accelerator-based boron neutron capture therapy demonstration device(AB-BNCT) located in Yangtze River Delta region is being build recently. The project is held by “Xi’an Jiaotong University-Huzhou Neutron Science Laboratory” joint lab established by Xi’an Jiaotong University and Huzhou Industrial Group. The AB-BNCT facility requires a proton beam of 30 mA@40 keV at RFQ entrance, with its beam duty cycle between 0.5%-100%, and its normalized root mean square emittance less than 0.2 π.mm.mrad. Ion source group of Peking University (PKU) is in charge of the proton ion source and its low energy beam transportation section (LEBT). A PKU type compact permanent magnet 2.45 GHz ECR ion source (PKU-Type PMECR) and a two solenoid LEBT is under development for this purpose. So far, the PMECR ion source conditioning is complete and all parameters are better than required for this facility. The details will be presented in the present paper.
Ion source developments to supply mono & multi charged ion beams to the new NHa C400 hadrontherapy system.
Authors: Maunoury L. , Velten P. , Donzel X. , Engelen V. , Collignon G. , Sortais P. , Perrussel J. , Paliard P. , Bérard D. 
Published: May 2024

Abstract
Normandy Hadrontherapy (NHa) is developing, in collaboration with Ion Beam Applications (IBA), a full hadrontherapy treatment solution based on a new multiparticle cyclotron. 12C6+ and 4He2+ ions will be accelerated up to 400 MeV/u and (H2)+ up to 260 MeV/u. Three different ion sources will be carried out for each accelerated particle: the mono-charged ion source (H2)+ and low charged ion source He2+ are provided by the Polygon Physics (PP) company. The carbon ion source is under development at NHa in collaboration with IBA and PP. The (H2)+ ion source is an industrial Tubular ECR Source (TES) fitted for the needs of the NHa C400 cyclotron (30 µA of (H2)+). The He2+ ion source is a classic 10 GHz ECR type with a new concept because the complete source is set inside a vacuum chamber and it runs under 10−6 mbar of gas residual pressure. The 12C6+ ion source is also an ECR type ion source operating at 14.5 GHz frequency, its design is under progress to produce a beam providing stability and reproducibility levels compatible with clinical use. The article will present the External Injection System of the NHa C400 cyclotron hence it will focus on the experimental results obtained with the (H2)+ ion source and preliminary outputs from the He2+ ECRIS. A presentation of the multicharged ECRIS design dedicated to the 12C6+ production will be done.