bluuebunny/crossref_metadata_2025 huggingface dataset:
iATPSnFR2: A high-dynamic-range fluorescent sensor for monitoring intracellular ATP
Authors: Marvin Jonathan S. , Kokotos Alexandros C. , Kumar Mukesh , Pulido Camila , Tkachuk Ariana N. , Yao Jocelyn Shuxin , Brown Timothy A. , Ryan Timothy A.
Published: May 2024

We developed a significantly improved genetically encoded quantitative adenosine triphosphate (ATP) sensor to provide real-time dynamics of ATP levels in subcellular compartments. iATPSnFR2 is a variant of iATPSnFR1, a previously developed sensor that has circularly permuted superfolder green fluorescent protein (GFP) inserted between the ATP-binding helices of the
ε
-subunit of a bacterial F
0
-F
1
ATPase. Optimizing the linkers joining the two domains resulted in a ~fivefold to sixfold improvement in the dynamic range compared to the previous-generation sensor, with excellent discrimination against other analytes, and affinity variants varying from 4 µM to 500 µM. A chimeric version of this sensor fused to either the HaloTag protein or a suitable spectrally separated fluorescent protein provides an optional ratiometric readout allowing comparisons of ATP across cellular regions. Subcellular targeting the sensor to nerve terminals reveals previously uncharacterized single-synapse metabolic signatures, while targeting to the mitochondrial matrix allowed direct quantitative probing of oxidative phosphorylation dynamics.
Synergistic induction of blood–brain barrier properties
Authors: Porkoláb Gergő , Mészáros Mária , Szecskó Anikó , Vigh Judit P. , Walter Fruzsina R. , Figueiredo Ricardo , Kálomista Ildikó , Hoyk Zsófia , Vizsnyiczai Gaszton , Gróf Ilona , Jan Jeng-Shiung , Gosselet Fabien , Pirity Melinda K. , Vastag Monika , Hudson Natalie , Campbell Matthew , Veszelka Szilvia , Deli Mária A.
Published: May 2024

Blood–brain barrier (BBB) models derived from human stem cells are powerful tools to improve our understanding of cerebrovascular diseases and to facilitate drug development for the human brain. Yet providing stem cell–derived endothelial cells with the right signaling cues to acquire BBB characteristics while also retaining their vascular identity remains challenging. Here, we show that the simultaneous activation of cyclic AMP and Wnt/β-catenin signaling and inhibition of the TGF-β pathway in endothelial cells robustly induce BBB properties in vitro. To target this interaction, we present a small-molecule cocktail named cARLA, which synergistically enhances barrier tightness in a range of BBB models across species. Mechanistically, we reveal that the three pathways converge on Wnt/β-catenin signaling to mediate the effect of cARLA via the tight junction protein claudin-5. We demonstrate that cARLA shifts the gene expressional profile of human stem cell–derived endothelial cells toward the in vivo brain endothelial signature, with a higher glycocalyx density and efflux pump activity, lower rates of endocytosis, and a characteristic endothelial response to proinflammatory cytokines. Finally, we illustrate how cARLA can improve the predictive value of human BBB models regarding the brain penetration of drugs and targeted nanoparticles. Due to its synergistic effect, high reproducibility, and ease of use, cARLA has the potential to advance drug development for the human brain by improving BBB models across laboratories.
The effects of bathymetry on the long-term carbon cycle and CCD
Authors: Bogumil Matthew , Mittal Tushar , Lithgow-Bertelloni Carolina
Published: May 2024

The shape of the ocean floor (bathymetry) and the overlaying sediments provide the largest carbon sink throughout Earth’s history, supporting ~one to two orders of magnitude more carbon storage than the oceans and atmosphere combined. While accumulation and erosion of these sediments are bathymetry dependent (e.g., due to pressure, temperature, salinity, ion concentration, and available productivity), no systemic study has quantified how global and basin scale bathymetry, controlled by the evolution of tectonics and mantle convection, affects the long-term carbon cycle. We reconstruct bathymetry spanning the last 80 Myr to describe steady-state changes in ocean chemistry within the Earth system model LOSCAR. We find that both bathymetry reconstructions and representative synthetic tests show that ocean alkalinity, calcite saturation state, and the carbonate compensation depth (CCD) are strongly dependent on changes in shallow bathymetry (ocean floor ≤600 m) and on the distribution of the deep marine regions (>1,000 m). Limiting Cenozoic evolution to bathymetry alone leads to predicted CCD variations spanning 500 m, 33 to 50% of the total observed variations in the paleoproxy records. Our results suggest that neglecting bathymetric changes leads to significant misattribution to uncertain carbon cycle parameters (e.g., atmospheric CO
2
and water column temperature) and processes (e.g., biological pump efficiency and silicate-carbonate riverine flux). To illustrate this point, we use our updated bathymetry for an Early Paleogene C cycle case study. We obtain carbonate riverine flux estimates that suggest a reversal of the weathering trend with respect to present-day, contrasting with previous studies, but consistent with proxy records and tectonic reconstructions.
Time Transfer in a 1839-km Telecommunication Fiber Link Demonstrating a Picosecond-Scale Stability
Authors: Guo 郭 Xinxing 新兴 , Hou 侯 Bing’an 丙安 , Liu 刘 Bo 博 , Yang 杨 Fan 凡 , Kong 孔 Weicheng 维成 , Liu 刘 Tao 涛 , Dong 董 Ruifang 瑞芳 , Zhang 张 Shougang 首刚
Published: May 2024

An implementation of high-precision time transfer over a 1839-km field fiber loop back link between two provincial capitals of China, Xi’an and Taiyuan, is reported. Time transfer stabilities of 6.5 ps at averaging time of 1 s and 4.6 ps at 40000 s were achieved. The uncertainty for the time transfer system was evaluated, showing a budget of 56.2 ps. These results stand for a significant milestone in achieving high-precision time transfer over a field fiber link spanning thousands of kilometers, signifying a record-breaking achievement for the real-field time transfer in both stability and distance, which paves the way for constructing the nationwide high-precision time service via fiber network.
Echoes of social experience: tracing the link between a sense of belonging in school physics classes and physics students’ persistence in higher education
Authors: Feser Markus Sebastian , Rabe Thorid , Haak Inka
Published: May 2024

The present study investigates on an exploratory level the extent to which the sense of belonging that university physics students experienced in their physics classes in secondary school impacts their intention to drop out or alter their course of study in higher education. Analysing data collected between April and June 2022 among first-year physics students at 20 German universities (N = 263), we find a significant and negative effect on the part of participants’ (remembered) sense of belonging in school physics classes on their intention to drop out or change their studies. Parallel mediation analysis further reveals that this effect is fully mediated by students’ current sense of belonging to physics and their university. Notably, the indirect effect via participants’ current sense of belonging to physics is approximately four times as high as the indirect effect via university belonging. These results emphasise the importance of social embeddedness in early physics experiences on students’ academic development in higher education. Limitations of these results as well as implications regarding a potential improvement of persistence and satisfaction within physics-related higher-education programs are outlined at the end of this paper.
Investigation of stabilization and survival of skyrmion vortices in the presence of magnetic field disorder in two-dimensional lattices: a case study for Janus dichalcogenides
Authors: Yüksel Yusuf
Published: May 2024

Due to the lack of inversion symmetry, very large Dzyaloshinskii–Moriya interaction (DMI) has been reported for a series of Janus monolayers of manganese dichalcogenides within the framework of first-principles calculations (Liang et al 2020 Phys. Rev. B 101 184401). However, from the viewpoint of potential applications, the current ongoing research mainly focuses on the magnetism in pristine two-dimensional (2D) materials exhibiting non-zero DMI, and the effects of disorder in such systems remain an open problem since the influence of randomness may create some drastic effects on the magnetism of low dimensional systems. Here, we present Monte Carlo simulation results regarding the magnetic properties of a 2D manganese based Janus dichalcogenide material

MnSTe

in the presence of quenched random magnetic fields where the local field variables have been sampled from a Gaussian distribution. For the selected benchmark material, it has been found that the magnetic skyrmion vortexes emerging at (10 K, 3 T) may survive in the presence of weak and moderate quenched randomness, which is important from the viewpoint of technological applications. In both the pristine and random field cases, the stabilization of magnetic skyrmions are achieved by the major contribution of the ferromagnetic exchange energy to the total energy of the system, and the materials exhibiting large DMI/exchange ratios may exhibit resilient magnetic skyrmion vortexes in the presence of weak and moderate amount of randomness.
Design and analysis of mode-matched decoupled mass MEMS gyroscope with improved thermal stability
Authors: Bashir Uzair , Bazaz Shafaat Ahmed , Saleem Muhammad Mubasher , Shakoor Rana Iqtidar , Tariq Muhammad Owais , Kumar Pirbhat
Published: May 2024

This paper presents an efficient design approach for microelectromechanical systems (MEMS) gyroscope considering the design constraint of MEMSCAP’s Silicon-on-Insulator Multi-User MEMS Processes (SOIMUMPs). A design for a decoupled mass MEMS resonant gyroscope with tuning electrodes is presented to minimize cross-axis coupling and optimize the gyroscope’s performance. The device features a size of

1.8

 

×
2.772

 m

m

2

. A decoupled mass MEMS gyroscope has been designed using a novel mechanical beam configuration that optimizes the structural design to reduce unwanted interactions between drive and sense axes motions. Mode order has been achieved by obtaining the first two modes as drive and sense modes at 9946.3 Hz and 10 202.7 Hz, respectively. Parallel plate electrostatic tuning electrodes have been added to adjust and match the drive and sense modes at the resonant frequencies of 9946 Hz. This mode matching is crucial for optimizing gyroscope performance, accuracy, and sensitivity. The effects of temperature variation on the performance of the designed decoupled mass MEMS gyroscope have been investigated, particularly in terms of its mode-matched operation achieved using tuning electrodes. Finite element method (FEM) simulations were conducted, demonstrating that thermal stability was achieved, and mode-matched operation was maintained within the temperature range of −40 °C to 80 °C. The gyroscope exhibits enhanced performance compared to existing MEMS gyroscopes under mode-matched conditions, featuring a lower temperature coefficient of frequency (TCF) at 0.0415 Hz °C−1 in the drive mode and 0.0165 Hz °C−1 in the sense mode. FEM analysis for the fabrication process tolerances has been done, where MEMS gyroscope’s resonant frequencies, output capacitance, output displacement, and sense mode quality factor have shown negligible changes to fabrication process tolerances. Transient analysis was conducted using CoventorWare MEMS+ 3D schematic, which was integrated with MATLAB Simulink to measure the MEMS gyroscope’s output response, which corresponded with the varying input angular velocity signal.
An infinite dimensional KAM theorem with normal degeneracy
Authors: Du Jiayin , Xu Lu , Li Yong
Published: May 2024

In this paper, we consider a classical Hamiltonian normal form with degeneracy in the normal direction. In previous results, one needs to assume that the perturbation satisfies certain non-degenerate conditions in order to remove the degeneracy in the normal form. Instead of that, we introduce a topological degree condition and a weak convexity condition, which are easy to verify, and we prove the persistence of lower dimensional tori without any restriction on perturbation but only smallness and analyticity.
Transformer-CNN hybrid network for improving PET time of flight prediction
Authors: Feng Xuhui , Muhashi Amanjule , Onishi Yuya , Ota Ryosuke , Liu Huafeng
Published: May 2024

Objective. In positron emission tomography (PET) reconstruction, the integration of time-of-flight (TOF) information, known as TOF-PET, has been a major research focus. Compared to traditional reconstruction methods, the introduction of TOF enhances the signal-to-noise ratio of images. Precision in TOF is measured by full width at half maximum (FWHM) and the offset from ground truth, referred to as coincidence time resolution (CTR) and bias. Approach. This study proposes a network combining transformer and convolutional neural network (CNN) to utilize TOF information from detector waveforms, using event waveform pairs as inputs. This approach integrates the global self-attention mechanism of Transformer, which focuses on temporal relationships, with the local receptive field of CNN. The combination of global and local information allows the network to assign greater weight to the rising edges of waveforms, thereby extracting valuable temporal information for precise TOF predictions. Experiments were conducted using lutetium yttrium oxyorthosilicate (LYSO) scintillators and silicon photomultiplier (SiPM) detectors. The network was trained and tested using the waveform datasets after cropping. Main results. Compared to the constant fraction discriminator (CFD), CNN, CNN with attention, long short-term memory (LSTM) and Transformer, our network achieved an average CTR of 189 ps, reducing it by 82 ps (more than 30%), 13 ps (6.4%), 12 ps (6.0%), 16 ps (7.8%) and 9 ps (4.6%), respectively. Additionally, a reduction of 10.3, 8.7, 6.7 and 4 ps in average bias was achieved compared to CNN, CNN with attention, LSTM and Transformer. Significance. This work demonstrates the potential of applying the Transformer for PET TOF estimation using real experimental data. Through the integration of both CNN and Transformer with local and global attention, it achieves optimal performance, thereby presenting a novel direction for future research in this field.
Enhancement of OCT en face images by unsupervised deep learning
Authors: Yuan Zhuoqun , Yang Di , Zhao Jingzhu , Liang Yanmei
Published: May 2024

Objective. The quality of optical coherence tomography (OCT) en face images is crucial for clinical visualization of early disease. As a three dimensional and coherent imaging, defocus and speckle noise are inevitable, which seriously affect evaluation of microstructure of bio-samples in OCT images. The deep learning has demonstrated great potential in OCT refocusing and denoising, but it is limited by the difficulty of sufficient paired training data. This work aims to develop an unsupervised method to enhance the quality of OCT en face images. Approach. We proposed an unsupervised deep learning-based pipeline. The unregistered defocused conventional OCT images and focused speckle-free OCT images were collected by a home-made speckle modulating OCT system to construct the dataset. The image enhancement model was trained with the cycle training strategy. Finally, the speckle noise and defocus were both effectively improved. Main results. The experimental results on complex bio-samples indicated that the proposed method is effective and generalized in enhancing the quality of OCT en face images. Significance. The proposed unsupervised deep learning method helps to reduce the complexity of data construction, which is conducive to practical applications in OCT bio-sample imaging.
Power deposition in the He bath induced by the Z gradient coil in the 11.7 T Iseult magnet: theory versus measurements
Authors: Aubert G , Guihard Q , Dubois O , Lannou H , Juster F-P , Belorgey J , Nunio F , Amadon A , Bonnelye C , Gras V , Le Ster C , Mauconduit F , Vignaud A , Quettier L , Boulant N
Published: May 2024

Gradient-magnet interactions increase with higher field magnets and stronger gradient coils. Perhaps the most sensitive aspect is magnet quench, which can be induced by a loss of superconductivity of the main coil caused by a rise of the temperature of the He bath with gradient activity. Predicting power depositions thereby can be a very valuable tool to avoid dangerous frequency zones but also eventually correct design flaws. In this work, we report model predictions compared to measurements of power deposition in the He bath of the Iseult 11.7 T magnet for the Z gradient coil axis.
Implicit particle-in-cell development for ion source plasmas
Authors: Savard N. , Fubiani G. , Baartman R. , Dehnel M.
Published: May 2024

Particle-in-Cell (PIC) codes used to study plasma dynamics within ion sources typically use an explicit scheme. These methods can be slow when simulating regions of high electron density in ion sources, which require resolving the Debye length in space and the plasma frequency in time. Recent developments on fully-implicit PIC models in curvilinear geometries have shown that these spatial/time scales can be significantly decreased/increased respectively, allowing for notable speed-ups in simulation time, and thus making it a potential tool for studying the physics of ion sources. For this purpose, a charge and energy conserving implicit PIC code has been developed in 1D to determine its potential for simulating bounded plasmas. In this paper, we use this model to simulate a 1D benchmark of a bounded plasma with fixed plasma density and electron/ion temperatures. The results are shown to compare well to the benchmark and to the results using an explicit PIC code. It is shown that the total amount of macro-particles used in the simulation is a better figure of merit for accurate results than the standard particles per cell used in literature. Significant speed-ups in computation time can be achieved for high plasma densities if the accuracy requirements are relaxed. In this case, we demonstrate the ability of the implicit PIC code to speed-up simulation time by nearly a factor of 12 compared to explicit PIC.
Initial Experimental Results of Producing Multicharged Ions Efficiently by Lower Hybrid Resonance Heating with Exciting Helicon Waves on Electron Cyclotron Resonance Ion Source
Authors: Kato Yushi , Harisaki Shuhei , Kubo Wataru , Iwahara Kouki , Fujimura Yushi
Published: May 2024

Based on experimental results, we considered the accessibility conditions for wave propagation in the magnetized plasma in an electron cyclotron resonance (ECR) ion source (ECRIS), and proposed introducing electromagnetic waves with frequencies lower than those of ECR. We generate the lower hybrid resonance (LHR) in the ECRIS by the electric field of the extra-ordinary mode (X-mode) on the helicon wave which additionally heat the electrons, and then it was conducted to improve the efficiency of multicharged ion generation successfully in over density condition. The electron energy distribution function obtained by the probe measurement shows an increase in the high-energy region in the corresponding LHR region. In this paper, for the first time we describe the initial experimental results on enhanced production of multicharged ions by the LHR of the low-frequency RF electromagnetic waves into the ECRIS.
Simple 3D PIC Analysis for Beam Phase Space Oscillation in RF Driven Negative Hydrogen Ion Source
Authors: Shibata T , Shinto K , Nakano H , Hoshino K , Miyamoto K , Ohkoshi K , Nanmo K , Ikegami K , Kawai I , Oguri H , Wada M
Published: May 2024

Temporal oscillation of the negative hydrogen ion (H−) beam in the Radio Frequency (RF) ion source is investigated by a simple 3D3V Particle-In-Cell (PIC) model. The model solves electron, proton, and H− transport processes in the extraction region. The calculation domain is from the vicinity of the beam aperture to the ground electrode. To understand the relation between the plasma density oscillation and the extracted H− beam characteristics, the input electron and proton fluxes from the driver region are varied parametrically with the fundamental J-PARC RF frequency (2 MHz). The numerical results give an idea of the main physical processes between the oscillations of the plasma parameters and the extracted H− ion trajectories depending on the plasma meniscus shape in the different RF phases.
Novel modelling of metal atoms diffusion and ion transport in ECR plasma relevant to ion sources and in-plasma nuclear physics studies
Authors: Pidatella A , Galatà A , Mishra B , Naselli E , Celona L , Lang R , Maimone F , Mauro G S , Santonocito D , Torrisi G , Mascali D
Published: May 2024

Metals can be injected into electron cyclotron resonance ion sources (ECRIS) via different techniques, among which resistive ovens are used to vaporize neutral materials, later captured by the energetic plasma that will step-wise ionize them, hence giving multiply charged ion beams for accelerators. Recently, PANDORA, a novel ECR plasma trap, has been conceived to perform interdisciplinary research spanning from nuclear physics to astrophysics, where in-plasma high charge states of metallic species are demanded. However, a full knowledge on the vaporization method and on the coupling of neutral atoms with plasma and its overall dynamics is still not available. Simulations, hence, are of fundamental relevance to improve the overall efficiency, reduce consumption of rare expensive isotopes, and to improve the ion source performance. We present a numerical study about metallic species suitable for oven injection in ECRIS, focusing on metals diffusion, transport, and wall deposition under molecular flow regime. We studied the metal dynamics with and without plasma. Results underline the plasma role on a space-dependent conversion yield, reflecting the strongly inhomogeneous ECR plasma. The plasma and its parameters have been modelled using an established self-consistent particle-in-cell model. The numerical tool is conceived for the PANDORA plasma trap but can be extended to other ECR plasmas and traps. As test cases we studied the 134Cs and 48Ca radioisotopes, as metals of interest for the modern nuclear physics. A focus is given on the β-decaying 134Cs, as an application case for PANDORA, providing quantitative estimates of the γ-detection signal-poisoning effect by neutral metals deposition at the chamber wall.
Installation and first results of a 1.1 kW TWT system for the AECR-U based ion source at UMCG-Partrec
Authors: Kremers H R , Jones B N , Brandenburg S , Gerbershagen A
Published: May 2024

To meet the demand for intense highly charged stable ion beams for medical and nuclear physics a traveling-wave-tube (TWT) based RF generator has been installed and is in commissioning at the Advanced Electron Cyclotron Resonance Upgrade (AECR-U) ion source at the UMCG-PAR-TREC facility. The generator comprises 2 x 750W in-phase combining TWT RF generators with an output frequency range of 12.75-14.5 GHz. Frequency scanning routines have been incorporated in the control software which makes it possible to identify intense and stable ion-beam regimes within the plasma-heating frequency domain. The new RF generator replaces a 14.1 GHz fixed frequency klystron. In this paper we present the setup, the scanning methodology, the first measurements, and discuss the frequency scans measured from a helium and a xenon beam. These results improve the stability and increase the beam intensity at the UMCG-PARTREC facility.
Development of a new J-PARC-made internal antenna for the J-PARC RF-driven H− ion source
Authors: Shinto K , Shibata T , Ohkoshi K , Nanmo K , Kawai I , Ikegami K
Published: May 2024

We have been conducting the test of a new J-PARC-made internal antenna for the J-PARC RF-driven cesiated H− ion source. During the test of high-density plasma production by the antenna, we monitored the outgassing characteristics of the antenna by measuring the mass spectrum of the source gas and optical emission spectrum of the plasma. It is confirmed that no remarkable impurities were detected from the new antenna. The observed emittances of the H− beam extracted by using the new antenna were similar to those by using the SNS-made antenna. To accelerate the endurance test of the new antenna, we applied the antenna for the high-density plasma production to the 5% duty factor (1 ms pulse width with 50 Hz repetition rate) with the 2 MHz RF input power of approximately 60 kW at the ion source test stand. These values are much higher than those in the J-PARC nominal operation; 0.8 ms pulse width with 25 Hz repetition rate (the duty factor of 2%) with the RF input power of approximately 30 kW. The paper describes the results of the characteristics of the new J-PARC-made antenna.
HVE ion sources for medium and high-energy accelerator systems
Authors: Annaluru A. , Mous D.J.W. , Walet R.C.
Published: May 2024

Since decades, High Voltage Engineering (HVE) manufactures particle accelerator systems for research and industry. HVE’s product line includes Singletron and Tandetron accelerator systems with terminal voltages of up to 6 MV. They are dedicated to a wide range of applications including ion implantation and irradiation, Ion Beam Analysis (IBA), Accelerator Mass Spectrometry (AMS), and neutron reference fields. In this paper, we give an overview of the different positive and negative ion sources that are applied in these systems. We focus especially on the recent development and the performance of a compact 2.45 GHz permanent magnet ECR bipolar ion source (HVE Model SO-160), used for negative light-ion injection into tandem accelerators. It generates high-current, low-emittance light-ion beams at 30 keV energy. The novelty in the design of this ion source is that it combines direct negative extraction for H
− with positive extraction for He
+ that is followed by charge exchange to He
− in a Na-based electron donor canal. The source produces in excess of 250 eµA of H
− and more than 20 eµA of He
−. It is expected the design allows for substantially higher currents, especially for H
−.
Research and development activities to increase the performance of the CAPRICE ECRIS at GSI
Authors: Maimone F. , Andreev A. , Galonska M. , Hollinger R. , Lang R. , Mäder J. , Patchakui P.T.
Published: May 2024

At GSI the CAPRICE ECRIS is in operation to deliver high charge state ion beams from gaseous and metallic elements to the accelerator facility. A test campaign has been carried out at the ECR test bench to fulfill the demand for higher intensity and stability of high charge state ions and for mixed ion beams. The ion beam stability has been monitored by an Optical Emission Spectrometer (OES), which has been already used to check the plasma and the temperature of the resistively heated oven during metal ion beam operation, particularly for Ca ion beams. During the test campaign, it was investigated that the OES can be used for monitoring the stability of ion beams from gaseous elements and mixed ion beams, and the main achieved results are reported. The ion beams extracted from the ECRIS have been simulated with a particle tracking code in order to study and improve the beam matching into the RFQ. The preliminary results of the study together with possible modifications of the extraction column are presented.
Dual Frequency Enhancement of the Supernanogan Multi-Charged Ion Source at TRIUMF ISAC Facility
Authors: Jayamanna K. , Adegun J. , Ames F , Angus T. , Charles C. , Kiy S. , Lovera M. , Louie D. , Minato B. , Saminathan S. , Schultz B.
Published: May 2024

In 2008, a Supernanogan ECR ion source from PANTECHNIK was introduced in addition to an in-house developed microwave ion source and a surface ion source to complement the TRIUMF Offline Ion Source (OLIS) facility to provide highly charged ions to ISAC experiments. Originally, it employed a 400 W Travelling Wave Tube Amplifier (TWTA) for RF heating, but less than 50 W was enough to produce all the multi-charged beams required by the experiments. A 50 W solid-state amplifier was added for redundancy purposes, but we found a significant improvement when both were switched on at the same time. When properly optimized for the dual frequency, less than ten times the total power is needed to produce a similar charge state distribution with more current than the single frequency. The beam stability and the ability to extract higher charged ions also improved with the dual frequency enhancement. The simulation studies, operational experience, and results are discussed in this paper.
Multi-filament ion source for uniform ion beam generation
Authors: Bahng Jungbae , Kim Yuncheol , Lee Young-woo , Yu Jinsung , Nam Seung-Hee , Choi Bong-Hyuk , Jeon Yongbae
Published: May 2024

Ion beams are employed in various fields such as semiconductor manufacturing, surface modification and material science. The uniformity of ion beams is crucial in many applications, but conventional ion sources that use a single filament often limit the uniformity and intensity of the ion beam. This paper presents a study that aims to optimize a multi-filament ion source to enhance the uniformity of ion beams. The study includes a detailed explanation of the ion source components and design, methods for measuring ion beam uniformity with its experimental design, followed by results, analysis, discussions and conclusions, completed by suggestions for future research directions. The experimental results demonstrate that the use of a multi-filament ion source improves ion beam uniformity compared to a single-filament ion source. An optimal design for the ion source components and new approaches for improving ion beam uniformity are described. The study’s results provide important information for improving ion beam uniformity and offer a technical basis for providing high-quality products and services in various industries.
ASTERICS, a new 28 GHz electron cyclotron resonance ion source for the SPIRAL2 accelerator
Authors: Thuillier T. , Angot J. , Cernuschi A. , Giraud J. , Peaucelle C. , Kiener F , Lagorio E. , Perbet E , Sole P. , Shick S. , Vezzu F. , Simon D. , Allain H. , Berriaud C. , Cadoux T. , Felice H. , Fernandez-Mora E. , Guillo T. , Graffin P. , Kleymenov V. , Sinnana A. , Touzery R. , Trieste S. , Vallcorba R. , Dubois M. , Lemagnen F. , Osmond B. , Trudel A. , Goupillière D.
Published: May 2024

A new A/Q=7 injector is under development for the SPIRAL2 accelerator at Caen, France (NEWGAIN project). A new 28 GHz superconducting electron cyclotron resonance ion source named ASTERICS is under design for this project. The source features a modern cryostat and a large plasma chamber (91 mm radius and 600 mm length). The physical and technical motivations for a larger plasma volume are detailed and estimates of expected beam intensities enhancement are discussed. The source will mainly produce metallic ion beams: the concept of a temperature-controlled liner (up to 900°C) to stabilize high vapor pressure metal re-evaporation in the source is presented. The preliminary design of the ion source and its superconducting magnet are described.
Extraction of ion beam from laser ion source for direct plasma injection scheme
Authors: Takahashi K , Sasaki T , Kikuchi T , Ikeda S , Kanesue T , Okamura M
Published: May 2024

Laser ion sources are expected to be used in various applications of heavy ion beam technology. The plasma direct injection scheme (DPIS) is a method in which ion beams extracted from a laser ion source are directly injected into a radio frequency quadrupole (RFQ) linear accelerator. In this study, a new shape of the plasma electrode with a concave surface for the DPIS was proposed to inject a converging beam to a cavity of RFQ accelerator. This approach allows the use of a large-diameter extraction electrode, which is not limited by the aperture of the RFQ electrode rods. The DPIS, using the concave surface electrode, was employed to accelerate C6+ ion beams. The results indicated that both the beam current and the number of ions increased nearly twice with the proposed electrode shape compared to values obtained with the conventional electrode. This enhancement corresponded to the increased extraction area of the beam.
Effect of solenoidal magnetic field on ion charge state distribution in laser ion source
Authors: Ishikuro K , Takahashi K , Sasaki T , Kikuchi T , Hasegawa J , Tamura J , Horioka K , Takayama K
Published: May 2024

Applying a solenoidal magnetic field to a laser produced plasma is a method to increase the ion beam current supplied from a laser ion source to applications. The purpose of this study is to investigate the effects of the solenoid magnetic field on the charge state distribution of the ion beam extracted from the laser ion source. A plasma generated by a Nd: YAG laser was injected into the solenoid lens with a length of 25 mm. The current waveforms of ion beams extracted from the laser produced plasmas were measured as a function of solenoidal field strength. In addition, the variation of beam current waveforms for each charge state ion was investigated. The results indicated that the charge state distribution in the plasma was kept after focusing by the solenoid magnetic field.
Ti beam extraction from a laser plasma focused by a magnetic field of a solenoid
Authors: Kashiwagi H , Yamada K , Hosoya S
Published: May 2024

Laser ion sources (LISs) have the advantages of generating plasma from various solid targets and quickly switching the ion species by changing the target. Given these features, we aimed to develop a LIS for an ion implanter that requires a wide variety of ion species. The plasma generated by the LIS diffuses three-dimensionally with a wide angular distribution, such that only a small fraction of the generated ions reaching the extraction electrode aperture is extracted as a beam. With this procedure, the beam intensity is insufficient for the implanter LIS, which uses a laser with lower energy than the conventional LIS. To obtain a higher beam intensity by increasing the number of ions reaching the beam extraction electrode aperture, a plasma transport system with a linear solenoid magnet was installed immediately after the LIS chamber to focus the plasma by a magnetic field. In the Ti plasma focusing experiment using this system, the beam intensity increased up to 6.7 times compared to that of the case without a magnetic field. This result demonstrates that plasma focusing by a magnetic field is effective for increasing the beam intensity.
Visible camera-based diagnostic to study negative ion beam profiles in ROBIN ion source
Authors: Dash Sidharth , Bandyopadhyay Mainak , Pandya Kaushal , Bhuyan Manas , yadav Ratnakar , Mistri Hiren , Singh Mahendrajit
Published: May 2024

Ensuring ion beam quality is of prime importance concerning the design of large-size neutral beam injectors(NBIs). Homogeneity, divergence, and beam energy are three crucial parameters defining beam quality. ROBIN(RF-Operated Beam source in India for Negative ions) source is one such prototype for extracting H− ion beam from hydrogen plasma. The extracted beam interacts with background neutrals and emits photons. These emissions are proportional to current density and the visible range emissions are used to characterize the beam using CCD cameras. The observed vertical emission profiles depict Gaussian-type asymmetric wings with a tilted flat-top that suggest non-uniform beam groups from the two grid segments. Divergence data extracted from the camera decreases with the acceleration voltage sweep. A strong correlation of the camera divergence data with calorimeter measurements was observed. A numerical beam model is in development to provide more insight into this correlation and pave the way to study beam group interaction.
Design of the beam transport optics of TRIUMF’s new 300 keV H− ion source terminal
Authors: Saminathan S. , Baartman R. , Bylinskii Y. , Ilagan M. , Jayamanna K. , Jovicic N. , Law O. , Lovera M. , Matchetto M. , Minato B. , Planche T. , Portilla D.
Published: May 2024

An ion beam transport system has been designed to transport a highly intense and bright beam extracted from the H− ion source. This new system will be installed at the new injection terminal for the TRIUMF’s 500 MeV H− cyclotron. The low energy part of the transport section (25 keV) in the injection terminal has been designed with magnetic optical elements in order to maintain space charge neutralization. The injection terminal includes a permanent magnet lens, magnetic steerers, a pulser, a beam dump, and a 300 kV acceleration column with electron and positive ion suppressor rings. Beam optics calculations have been performed, including space charge effects up to 1 mA. The simulation results of the beam optics design are presented in this paper.
The Development of Pepper-Pot Emittance Monitor in Gunma University
Authors: Nakao M , Kanda H , Takeda K , Hattori K , Itoh M , Fukuda M , Miyawaki N , Adachi S , Kurashima S , Hara T , Wakui T , Yorita T , Chong T H , Shinozuka T , Morita Y , Matsuda Y , Yasuda Y
Published: May 2024

The pepper-pot emittance monitor is a device that can measure the phase space distribution of the beam rapidly. We have introduced one at the ion source test stand of Gunma University. We confirmed that the phase space distribution can be measured accurately comparing to the existing wire-slit type emittance monitor.
The Child Langmuir Illusion
Authors: Faircloth D. , Kalvas T , Kosonen S , Tarvainen O , Toivanen V
Published: May 2024

A Particle in Cell (PIC) model of ion beam extraction from a plasma provides strong evidence that the origin of the observed V(3/2) relationship between the applied extraction voltage and beam current is caused by meniscus shape and collimation on the extraction electrode, not by space charge limited extraction. Excellent correlation between the PIC model, a gun code and experiment is shown for 100 µA Ar+ beams. The s-shape in the emittance phase space is shown to be caused by the radial electric field created by the external edge of the plasma electrode.
A high-intensity, low-energy heavy ion source for a neutron target proof-of-principle experiment at LANSCE
Authors: Cooper Andrew L , Mosby S , Reifarth R , Couture A , Bennett E , Gibson N , Gorelov D , Keith C , Lovell A , Misch G , Mumpower M
Published: May 2024

The capability to directly study neutron capture reactions on radionuclides with half-lives on the of order minutes would allow key cross section measurements in nuclear astrophysics and energy applications. However, such experiments with stationary targets are currently impossible because of signal detection and target sample fielding issues. To overcome these challenges, a neutron target facility is being developed to permit neutron capture experiments on unstable isotopes in inverse kinematics at the Los Alamos Neutron Science Center (LANSCE). This next-generation facility will consist of a heavily moderated, high-intensity spallation neutron target coupled with a radioactive ion beam storage ring. A proof-of-principle experiment is underway to demonstrate this neutron target concept at LANSCE in the near term with stable ions and without a storage ring. Here, mA-level beams of 10-50 keV heavy ions exhibiting large resonant neutron capture cross sections will be generated by a new ion source, transported through a large-volume neutron moderator surrounding an adjacent spallation target driven by the LANSCE accelerator, and collected downstream of the moderator for subsequent decay-counting measurements. The neutron density within the moderator will be obtained from these decay yields and compared with Monte Carlo N-Particle (MCNP) simulation results. The science application, operational requirements, and performance objectives for this heavy ion source will be presented.
Status update of the ATLAS ECR ion sources at Argonne National Laboratory
Authors: Scott R H , McLain J , Vondrasek R C
Published: May 2024

The Argonne Tandem Linac Accelerator System (ATLAS) at Argonne National Laboratory (ANL) typically operates 24/7 with weekly ion beam changes and an annual 1 month maintenance period. Due to recent installations and upgrades at ATLAS, user demands for new beams and higher intensities have expanded an already diverse operational envelope of both electron cyclotron resonance ion sources (ECRIS), ECR2 and ECR3. A variety of material introduction techniques including sputter, oven, reduction and gas feed were used to meet the challenge of an intense run schedule. With two ECRIS available to feed the accelerator, beam development and preparation were able to occur concurrently with ATLAS programmatic activities. Highlights of operational experiences and improvements with ECR2 and ECR3 over the last 2 years are presented.
Generation of plasma from multiple targets by laser ion source for TIARA ion implanter
Authors: Yamada K , Kashiwagi H , Hosoya S
Published: May 2024

We investigated a laser ion source for use as an ion source for the ion implanter in Takasaki Ion Accelerators for Advanced Radiation Application to increase the number of ion species that can be produced and to enable rapid switching of ion species. Herein, we analyzed the charge state distribution of ions in a laser plasma generated through irradiation of graphite, titanium, copper, and tantalum targets with 30 mJ Nd:YAG laser to determine the particle number of low-charge ions per pulse at 1.1 m from the target. The particle number of singly charged ions could be increased by adjusting the laser power density. For carbon, titanium, and tantalum, the particle numbers were in the order of 1010 ions per pulse, whereas for copper, the particle numbers were in the order of 109, lower than for other target materials.
Progress of the laser ion source upgrade (LION2) for RHIC and NSRL program at Brookhaven National Laboratory
Authors: Kanesue T , Beebe E , Coe B , Ikeda S , Kondrashev S , Liaw C , Okamura M , Olsen R , Rodowicz T , Schoepfer R , Smart L , Weiss D , Zhang Y
Published: May 2024

At Brookhaven National Laboratory (BNL), the LION2 ion source is being constructed to replace an existing laser ion ablation ion source (LIS) at the EBIS facility, which provides heavy ion beams of multiple ion species for the operation of NASA Space Radiation Laboratory (NSRL) and Relativistic Heavy Ion Collider (RHIC). The LION1 ion source currently provides singly charged ions of Li, B, C, O, Al, Si, Ca, Ti, Fe, Cu, Zr, Nb, Ag, Tb, Ta, W, Au, Bi, and Th with a rapid-species-change capability. An electron beam ion source, Extended-EBIS captures, confines, and ionizes the ions to high charge state, suitable for injection and acceleration by an RFQ accelerator. Typically, single pulses of the LIS ion species for NSRL are changed sequentially during Galactic Cosmic Ray experiments, while multiple pulses of a given ion beam are provided quasi-simultaneously for RHIC. LION2 will have the same capability of the rapid-species-change with improved beam performance and reliability. LION2 is being constructed in a remote assembly location and is expected to finish in December 2023. The removal of LION1 and installation of LION2 is planned during the December 2023 or summer 2024 shutdown.
Effect of rolling temperature on microstructure and mechanical properties of hot-rolled Mg-Al-Ca-Zn-Mn alloys
Authors: Chen Qingrui , Li Chunxiao , Lv Ning , Chen Rongshi , Mao Yaozong
Published: May 2024

In order to address the problems of traditional magnesium alloys, such as the easy formation of basal texture and poor plasticity at room temperature, a multivariate micro alloyed Mg-1Al-0.9Ca-0.5Zn-0.4Mn material has been designed by taking advantage of the unique role of solute atoms such as Ca. The effects of its rolling process on grain size, second phase, texture, and tensile properties were compared and analyzed. The results show that the rolling temperature will significantly change the organization and properties: a small number of large-sized reticulate phases, linear phases, and granular phases will exist along the rolling direction inside the Mg-1Al-0.9Ca-0.5Zn-0.4Mn alloy. When the rolling temperature is raised, it will change the number and size of the second phase and microstructure morphology. For three plates rolled at 300°C, the best-combined strength-plasticity mechanical properties were presented in this work; elongation is 2.5%, tensile strength is 167 MPa, and yield strength is 146 MPa along the RD, respectively. Besides, some larger-sized phases still exist in this alloy, which affects its mechanical properties.
The design and research of the rotating cabin body in an electro-optical pod
Authors: Yao Jianning , Hou Yunlei , Zhang Haina , Zhang Yong , Su Jianhua , Xi Xiaopeng , Duan Jinjing
Published: May 2024

This paper introduces the development process of a rotating cabin body, which is the core component of an electro-optical pod. Firstly, two-window structures were designed according to the demand. The wind resistance of these two-window structures within the rotating range was simulated, analyzed, and compared. on this basis, the optimal window structure was selected. Subsequently, finite element analysis was conducted on the selected form of the cabin body to verify its structural strength and stiffness, including the static analysis and modal analysis. On the basis of sufficient design and analysis, the rotating cabin body was manufactured. After testing and debugging, the electro-optical pod was mounted on an aircraft for flight testing. The experimental results verified the rationality of the design of the electro-optical pod.
Automatic assembly of in-cabin components based on hybrid guidance of binocular vision and laser tracker
Authors: Zhang Xiaolin , Wang Zanqin , Yang Chuancheng , Wang Dahuan , Feng Jianjun , Wang Shaoke
Published: May 2024

In order to automate the assembly of a certain type of missile cabin interior components, a new assembly method with a mixture of binocular vision and laser tracker is proposed. The laser tracker is used to determine the coarse position and posture relationship between the cabin segment and the robot. The two binocular vision systems use skeleton extraction and hit-and-miss transformation to extract target cross-hatch features, perform pose fitting, and obtain the fine pose relationship between the target and the component. Twenty full-process simulations are performed on the CoppeliaSim platform. The results show that, with a pixel accuracy of 0.053 mm, the mean value of the position error of the assembly is 0.614 mm with a standard deviation of 0.270, and the mean value of the posture angle error of the assembly is -0.036° with a standard deviation of 0.178. This method realizes automatic grasp-release action and improved absolute positioning accuracy of the robot in the uncalibrated case and can meet the automation and precision needs of production in the final assembly plant.
Effects of annealing on the microstructure and performance of thin-film Pt resistance temperature sensors: experiments and finite element simulations
Authors: Liu Shu-Hang , Zhang Xin-Ping , Cao Shanshan , Zhou Min-Bo
Published: May 2024

Platinum resistance temperature sensors have a wide range of applications in various fields, where a high temperature coefficient of resistance (TCR) is a crucial requirement. In this study, thin-film Pt resistance temperature (TPRT) sensors were fabricated on an Al2O3 substrate using a micro-electro-mechanical system (MEMS) based surface micromachining process, and Pt resistance wafers were annealed at a temperature range from 500°C to 800°C using rapid thermal process (RTP). Experimental and simulation results show that TPRT sensors fabricated on the substrate with a rough surface exhibit lower thermal stress. Meanwhile, more pores appear in the Pt thin film, reducing TCR. However, high temperature annealing significantly influences the microstructure of the Pt film and brings about an obvious increase in TCR despite, introducing thermal stress at the interface. Considering the impact of the heat treatment process, the fabricated TPRT sensors demonstrate excellent performance with a TCR of 3512 ppm/°C.