bluuebunny/crossref_metadata_2025 huggingface dataset:
High performance of an innovative cable-in-conduit conductor with CWS cable pattern
Authors: Guo Zichuan , Liu Yunhao , Dai Chao , Nijhuis Arend , Wang Wei , Zhou Chao , Qin Jinggang
Published: May 2024

Cable-in-conduit conductors, known as CICCs, were developed for constructing superconducting coils in tokamak fusion reactors. To achieve large currents in high magnetic field, CICCs were utilized with a short-twist-pitch (STP) cable pattern to prevent irreversible performance degradation, but also inducing higher AC losses. Institute Of Plasma Physics Chinese Academy Of Sciences (ASIPP) designed and manufactured three innovative CICCs, all featuring CWS (copper wire with a STP wound around superconducting strands with a long-twist-pitch) structure to increase both the current density and structure stiffness of CICC cable. These CICCs had the same new CWS cable pattern but the Nb3Sn superconducting strands were from different suppliers. All samples were subsequently tested under electromagnetic cycling tests in SULTAN. For similar electromagnetic performance degradation, the Lorentz load threshold of the CWS cable pattern exhibited to be higher than that of STP cable pattern. Moreover, the AC losses of CWS were 15% lower than that of STP cable pattern for low frequencies of the applied alternating magnetic field. Both results indicated that the CWS cable pattern has a higher margin of engineering safety and lower AC losses than STP cable pattern under the target operating conditions. This provides new insights in finding solutions for optimizing the CICCs’ cable pattern and preventing its electromagnetic performance degradation.
Crossover from Cooper-pair hopping to single-electron hopping in Pb
x
(TiO2)

1
−
x

granular films
Authors: He Zhi-Hao , Han Zi-Yan , Gao Kuang-Hong , Wang Zi-Wu , Li Zhi-Qing
Published: May 2024

The electrical transport properties of Pb
x
(TiO2)

1
−
x

(x being the Pb volume fraction and ranging from ∼0.45 to ∼0.72) granular films are investigated experimentally. The charging energy of the Pb granules is reduced to less than the superconducting gap of Pb granules for the low temperature insulating films by using high-k dielectric TiO2 as the insulating matrix. For the insulating films in the vicinity of the superconductor-insulator transition, Cooper-pair hopping governs the low-temperature hopping transport. For these films, the low-temperature magnetoresistance is positive at low field and the resistivity vs temperature for Cooper-pair hopping obeys an Efros–Shklovsii-type variable-range-hopping law. A crossover from Cooper-pair-dominated hopping to single-electron-dominated hopping is observed with decreasing x. The emergence of single-electron-dominated hopping in the more insulating films is due to the causation that the intergrain Josephson coupling becomes too weak for Cooper pairs to hop between adjacent Pb granules.
Facile synthesis of eco-friendly mango peel-derived porous carbon for optimizing microwave absorption
Authors: Qamar Tauqeer Haidar , Ma Lei , Hassan Sibt ul , Ahmed Nouman , Jamali Sain Bux , Huang Shengxiang , Deng Lianwen
Published: May 2024

An environment-friendly and cost-effective method to deal with electromagnetic pollution is fabricating porous carbon from biomass as a raw material with a simple technique. The purpose of this research is to create porous carbon from mango peel biomass for optimizing microwave absorption. The resulting porous carbon (PC) has the potential to be an effective microwave absorber. Scanning Electron Microscopy (SEM) depictions also revealed the porous carbon with homogeneous shapes and uniform size distribution. Complex permittivity studies were performed to evaluate their microwave absorption capabilities, resulting in a high reflection loss of −50.2 dB at a thickness of 2.1 mm and an effective absorption bandwidth (EAB) of 3.39 GHz for the sample carbonized at 800 °C. The exceptional microwave absorption ability of porous carbon (PC) can be attributed to its effective impedance matching and consequent attenuation of microwaves through dielectric loss. This research introduces a novel biomass source, readily available in nature, which can be easily processed to enhance microwave absorption properties.
A sensitive methane gas sensor based on sagnac interferometer with a cryptophane-A film-coated birefringent photonic crystal fiber : design and FEM simulation
Authors: Li Yuxin , Chen Hailiang , Li Hongwei , Yin Zhiyong , Gu Mingqi
Published: May 2024

As being sensitive to methane gas, cryptophane-A is widely used in fiber optic methane gas sensors. In order to further improve the sensitivity, a Sagnac interference (SI) was constructed with a cryptophane-A film coated birefringent photonic crystal fiber (PCF) to realize the methane gas sensing. Cryptophane-A film absorbs the methane gas and as a result its refractive index decreases linearly with the increasing of methane gas concentration. Simulation results utilizing the finite element method demonstrate that sensitivity reaches 124.4 nm/% when the methane concentration ranges from 0% to 3.5%. The sensor is relatively simple to prepare and can achieve high sensitivity, which has potential application in the field of monitoring methane gas leakage.
Revisiting the stochastic QCD axion window: departure from equilibrium during inflation
Authors: Briaud Vadim , Kadota Kenji , Mukohyama Shinji , Talebian Alireza , Vennin Vincent
Published: May 2024

If dark matter is made of QCD axions, its abundance is determined by the vacuum expectation value acquired by the axion field during inflation. The axion is usually assumed to follow the equilibrium distribution arising from quantum diffusion during inflation. This leads to the so-called stochastic window under which the QCD axion can make up all the dark matter. It is characterised by 1010.4 GeV ≤ f ≤ 1017.2 GeV and H
end > 10-2.2 GeV, where f is the axion decay constant and H
end is the Hubble expansion rate at the end of inflation. However, in realistic inflationary potentials, we show that the axion never reaches the equilibrium distribution at the end of inflation. This is because the relaxation time of the axion is much larger than the typical time scale over which H varies during inflation. As a consequence, the axion acquires a quasi-flat distribution as long as it remains light during inflation. This leads us to reassessing the stochastic axion window, and we find that 1010.3 GeV ≤ f ≤ 1014.1 GeV and H
end > 10-13.8 GeV.
Laser beam effect on the entanglement of elastic collisions in quantum plasma
Authors: Roozehdar Mogaddam Ramin , Sepehri Javan Nasser , Mohammadzadeh Hosein
Published: May 2024

In the quantized field formalism, using Kramers–Henneberger unitary transformation as the semi-classical counterpart of Block–Nordsieck transformation, the dynamics of entanglement during the low energy scattering processes in bi-partite systems at the presence of a laser beam fields are studied. The stationary-state Schrodinger equation for the quantum scattering process is obtained for such systems. Then, using partial wave analysis, we introduce a new form of entanglement fidelity considering the effect of high-intensity laser beam fields. The effective potential of hot quantum plasma including plasmon and quantum screening effects is used to obtain the entanglement fidelity ratio as a function of the laser amplitude, and plasmon and Debye length parameters for the elastic electron-ion collisions. It is shown that the plasma free electrons oscillations under interaction with laser beam fields improve the correlations between charged particles and consequently lead to the increase in the system entanglement.
Two-dimensional Sb net generated nontrivial topological states in SmAgSb2 probed by quantum oscillations
Authors: Yuan 袁 Jian 健 , Shi 石 Xian-Biao 贤彪 , Du 杜 Hong 红 , Li 李 Tian 田 , Xi 郗 Chuan-Ying 传英 , Wang 王 Xia 霞 , Xia 夏 Wei 威 , Wang 王 Bao-Tian 保田 , Zhong 钟 Rui-Dan 瑞丹 , Guo 郭 Yan-Feng 艳峰
Published: May 2024

The REAgSb2 (RE = rare earth and Y) family has drawn considerable research interest because the two-dimensional Sb net in their crystal structures hosts topological fermions and hence rich topological properties. We report herein the magnetization and magnetotransport measurements of SmAgSb2 single crystal, which unveil very large magnetoresistance and high carrier mobility up to 6.2 × 103% and 5.58 × 103 cm2⋅V−1⋅s−1, respectively. The analysis of both Shubnikov–de Haas and de Haas–van Alphen quantum oscillations indicates nontrivial Berry phases in the paramagnetic state while trivial Berry curvature in the antiferromagnetic state, indicating a topological phase transition induced by the antiferromagnetic order. It is also supported by the first-principles calculations. The results not only provide a new interesting topological material but also offer valuable insights into the correlation between magnetism and nontrivial topological states.
Initial Experimental Results on Ion Cyclotron Resonance Heating Selectively Mixed Low Z Ions to Enhance Production Efficiency of Multicharged Ions on Electron Cyclotron Resonance Ion Source
Authors: Kato Y , Harisaki S , Kubo W , Fujimura Y , Iwahara K
Published: May 2024

According to the accessibility conditions of wave propagation in the magnetized plasma of an electron cyclotron resonance (ECR) ion source (ECRIS), it is speculated that the essential factor that determines the limitations in the multiply charged ion currents is the left-hand polarization wave cutoff (L-cutoff). It is necessary to overcome this limitation, we proposed the introduction of ion cyclotron resonance (ICR) or lower hybrid resonance (LHR) by lower frequency waves. We conduct heating low-mass ions selectively in enhanced producing multiply charged ion by mixing low-mass element gas, which has been conventionally performed in ECRIS, or relaxation of the potential well based on the existence of resonant electron particles by ECR. This paper will describe the initial experimental results of ICR application by introducing low-frequency RF electromagnetic waves in the ECRIS.
First numerical evidence of the two-close frequency heating effect on electron cyclotron resonance ion sources
Authors: Galatà A , Biri S , Finocchiaro G , Gallo C S , Mascali D , Mishra B , Naselli E , Pidatella A , Rácz R , Torrisi G
Published: May 2024

The two-close frequency heating (TCFH) is a new implementation of the well-known two frequency heating. In TCFH, the two frequencies differ around 200-300 MHz each other in order to establish two contiguous ECR resonance zones. TCFH has been proved to be a powerful technique to suppress plasma instabilities in Electron Cyclotron Resonance Ion Sources (ECRIS), as well as to improve their performances. Its beneficial effect, compared to the application of a single frequency, is always deduced from the extracted charge states distributions and from the detection of the plasma self-emission in the X-ray and microwave ranges. This paper presents the first approach to a numerical description of the two-close frequency effect, based on the relevant plasma parameters of the ECRIS setup operating at ATOMKI-Debrecen. Simulations have been performed by our PIC-Full Wave code, joining electron kinetics and FEM solution of Maxwell equations in a cold plasma model. Results on plasma electron density and energy distribution will be shown, together with a direct comparison with the already published data on X ray emission.
Design of a novel ECR ion trap facility for nuclear physics and fundamental plasma processes studies
Authors: Naselli E. , Santonocito D. , Biri S. , Celona L. , Finocchiaro G. , Galatà A. , Mauro G.S. , Mishra B. , Pidatella A. , Rácz R. , Torrisi G. , Mascali D.
Published: May 2024

An innovative ECR ion trap facility, called PANDORA (Plasma for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry), was designed for fundamental plasma processes and nuclear physics investigations. The overall structure consists of three subsystems: a) a large (70 cm in length, 28 cm in inner diameter) ECR plasma trap with a fully superconducting B-minimum magnetic system (Bmax = 3.0 T) and an innovative design to host detectors and diagnostic tools; b) an advanced non-invasive plasma multidiagnostics system to locally characterize the plasma thermodynamic properties; c) an array of 14 HPGe detectors. The PANDORA facility is conceived to measure, for the first time, in-plasma β-decaying isotope rates under stellar-like conditions. The experimental approach consists in a direct correlation of plasma parameters and nuclear activity by disentangling - by means of the multidiagnostic system that will work in synergy with the γ-ray array - the photons emitted by the plasma (from microwave to hard X-ray) and γ-rays emitted after the isotope β-decay. In addition to nuclear physics research, fundamental plasma physics studies can be conducted in this unconventional ion source equipped with tens of detection and diagnostic devices (RF polarimeter, optical emission spectroscopy (OES), X-ray imaging, space and time-resolved spectroscopy, RF probes, scope), with relevant implications for R&D of ion sources for accelerator physics and technology. Several studies have already been performed in downsized nowadays operating ECRIS. Stable and turbulent plasma regimes have been described quantitatively, studying the change of plasma morphology, confinement, and dynamics of losses using space resolved X-ray spectroscopy.
Recent experiments on photo-assisted negative ion production in caesium sputter ion source at the JYFL Pelletron facility
Authors: Hossain A. , Tarvainen O. , Reponen M. , Kronholm R. , Julin J. , Kalvas T. , Toivanen V. , Kivekäs M. , Laitinen M.
Published: May 2024

We have measured the effect of a 15 W, 445 nm laser on Br− beam current produced by a SNICS ion source by systematically varying the ion source parameters, most importantly the target holder material, and temperatures of the ioniser and Cs oven. The target holder material has no significant effect on the observed photoenhancement of the beam current. The evidence shows that the laser allows reaching higher beam currents at low ioniser temperatures compared to running the source without the laser but at higher ioniser temperature. We have observed a priming effect, i.e. applying a number of laser pulses at certain ion source settings causes the beam current measured without the laser to increase significantly and remain high after ceasing the laser pulsing. These observations suggest that the photo-assisted effect is related to changes of the cathode caesium coverage. Finally, we report the results of our first attempts to sustain a stable beam current at the elevated level over several hours, achieved through active control of the laser power.
Plasma homogeneity over the extraction beamlet groups at the half size ITER negative ion source at ELISE test facility
Authors: Yordanov D. , Wünderlich D. , Wimmer C. , Riedl R. , Navarro A. , Fantz U. ,   NNBI Team
Published: May 2024

The negative ion source for neutral beam injection at ITER has to provide high-intensity and low-divergence negative hydrogen and deuterium ion beams. Extracting the negative ions from the plasma is inevitably accompanied by co-extraction of electrons, which can limit the source performance, especially in deuterium. Reducing the co-extracted electrons is done by applying a magnetic filter field. On the one hand, the filter field reduces the electron temperature and the amount of co-extracted electrons, on the other hand, it introduces ×

B
→

drifts. The drifts create a vertical plasma inhomogeneity in front of the extraction area and, consequently, an asymmetry of the co-extracted electrons. This motivated detailed studies on the vertical plasma inhomogeneity over the beamlet groups in the ELISE ion source using a movable Langmuir probe in deuterium plasma. It is demonstrated that the vertical distribution of the plasma potential changes together with the sheath, forming at the plasma grid – from electron repelling to attracting sheath. A repelling sheath reduces the flux of electrons from the plasma to the grid surface and consequently, more electrons are co-extracted. The attracting sheath collects the majority of electrons on the grid and reduces the co-extracted electrons.
The extraction of both positive and negative ions from a volume cusp H− ion source
Authors: Melanson Stephane , George Anand , Dehnel Morgan
Published: May 2024

The TRIUMF licensed H− ion source is known to produce 15 mA of H− ions, but some applications, such as cyclotrons, require the injection of both positive and negative ions. Furthermore, when using a tandem accelerator, there would be a benefit in using an ion source that can directly extract H− and He+. A charge exchange chamber would only have to be used with the He+ beam for the production of He−. In this paper, we present the conversion of the H− ion source to allow for the extraction of both positive (He+, H+,

H
2
+

and

H
3
+

) and negative (H− and D−) ions. In the modified design, up to 3 mA of protons and 2 mA of He+ can be extracted when using positive extraction power supplies and up to 5 mA of H− can be extracted when the polarity of the power supplies switched to negative extraction. We study how the ion source parameters affect the proton fraction and we look at the influence of the magnetic filter field in the plasma chamber.
Beam Optics Study during Long-Pulse MeV-Class Beam Operation for the ITER HNB
Authors: Tanaka Y , Kisaki M , Suzuki K , Hiratsuka J , Murayama M , Ichikawa M , Tobari H , Kashiwagi M
Published: May 2024

Neutral beam injectors for ITER require the beam divergence to be less than 7 mrad for both D− and H− negative ion beams. The time evolution of beam optics parameters of ITER-relevant high intensity has not been well understood due to the material capabilities of heat load. In this study, the time evolution of beam divergence has been successfully observed with the ITER-relevant perveance beam parameter for 0.5 MeV and 100 seconds pulse. For this purpose, a beam monitoring system based on a visible camera, which has been newly developed and installed in the MeV Test Facility, is used. As a result of this experiment, it is experimentally found that the time evolution of beam divergence exists even if the Iacc
and heat load to beam dump are stable. To reduce the time evolution of beam optics, the feed-back control of Iext
is under development in order to suppress the variation of conditions in the ion source.
Gas mixing and double frequency operation of the permanent magnet quadrupole minimum-B electron cyclotron resonance ion source CUBE-ECRIS
Authors: Toivanen Ville , Kalvas Taneli , Koivisto Hannu , Kosonen Sami , Tarvainen Olli
Published: May 2024

CUBE-ECRIS is a recently commissioned permanent magnet electron cyclotron resonance (ECR) ion source developed at the university of Jyväskylä accelerator laboratory. The special features of the new ion source design include an unconventional quadrupole minimum-B magnetic field structure and a slit beam extraction system necessitated by the line-shaped plasma loss fluxes. Gas mixing and double frequency operation are widely used methods to optimize high charge state ion production of conventional ECR ion sources. The work presented here demonstrates the applicability of these methods for boosting the high charge state beam currents of argon, krypton and xenon extracted from CUBE-ECRIS. Oxygen and helium were used as mixing gases and microwave frequencies between 10 and 11 GHz were used for single and double frequency operation. Gas mixing has a strong impact on the high charge state beam currents. For example, the highest observed charge state increased from 15+ to 19+ for krypton and from 16+ to 23+ for xenon with oxygen gas mixing. Double frequency operation provides an additional performance improvement, for example the currents of argon 9+ and 11+ beams, produced with gas mixing, increased 30% and 100% in double frequency operation at the same total power.
European effort to improve highly charged heavy ion beam capabilities with ECR ion sources (invited)
Authors: Koivisto H. , Andreev A. , Asfari Z. , Biri S. , Celona L. , Charbonnière L. , Charpentier C. , Dubois M. , Filliger M. , Galatà A. , Gall B. , Gallo C. S. , Galonska M. , Gammino S. , Gerbershagen A. , Jones B.N. , Kalvas T. , Kremers H.R. , Kronholm R. , Lang R. , Lemagnen F. , Leonardi O. , Maimone F. , Mascali D. , Mäder J. , Naselli E. , Pidatella A. , Rácz R. , Thuillier T. , Timonen O. , Toivanen V. , Torrisi G.
Published: May 2024

The European Electron Cyclotron Resonance Ion Source (ECRIS) community has more than 20 years of experience working together in various EU-funded projects. In the recent project, called ERIBS (European Research Infrastructure – Beam Services), the community will focus on improving ion beam services for the EURO-LABS (European-Laboratories for Accelerator Based Sciences) research infrastructures. The EURO-LABS is a four-year project funded by the Horizon Europe program of the European Commission for years 2022 - 2026. In the ERIBS collaboration the best expertise, know-how and practices of the ECRIS community will be exploited and transferred between the partners to take full advantage of the European ion source infrastructure. The aim is to extend the beam variety available for the European user community by developing beam production methods and techniques. This development includes further improvement of technologies related to high temperature ovens, axial sputtering and MIVOC method for all the participating laboratories. We will also aim to improve both short- and long-term plasma and beam stability, as well as methods for online monitoring of these conditions. This can be realized, for example, by optical emission spectroscopy, identifying kinetic plasma instabilities by means of hard x-ray detection and using online beam current monitoring systems. An example of the recent developments is the new collaboration proposed by the CNRS-IPHC team to synthesize enriched MIVOC compounds for the other ERIBS partners. For example, the team successfully prepared an enriched chromocene compounds, which were needed to produce intensive 54Cr and 50Cr beams for the JYFL and GANIL nuclear physics programs, respectively.
Evolution of ALISES 3 Light Ion Source at CEA Saclay
Authors: Dubois A , Delferriere O , Gauthier Y , Sauce Y , Tuske O
Published: May 2024

Since 1995, the Laboratory for Accelerator Studies and Development at CEA Saclay specializes in producing ECR intense Light Ion Sources, for high intensity proton or deuteron. The initial source SILHI (Source d’Ions Légers Haute Intensité) designed for IPHI accelerator in 1995 was the root of sources provided to laboratories worldwide, such as IFMIF, FAIR or SPIRAL2. In parallel, the Ion Source team started a new R&D program on high intensity ECR compact ion sources with the ALISES source family (Advanced Light Ion Source Extraction System). The years spent testing and improving ALISES v1&2 led us to design a new source, named ALISES v3. The development of this source gathers the advantages of each improvement tested on ALISES v1&2, to achieve an even smaller and pragmatic configuration. The manufacturing of ALISES v3 took place during the improvement of the BETSI test bench in 2018, from 50 kV to 100 kV. The goal of this source is to obtain the same characteristics as the original SILHI, with fewer parts and easier maintenance. This article describes the evolution of ALISES v3 and the beam characteristics at every stage. BETSI test bench is equipped with an Allison Scanner and a Faraday cup to analyse the emittance and the beam current.
Radioactive ion-beam development at SPIRAL1
Authors: Chauveau P. , Angot J. , Bosquet V. , Damoy S. , Delahaye P. , Dubois M. , Frigot R. , Hormigos S. , Jardin P. , Maunoury L. , Michel C. , Thomas J.-C.
Published: May 2024

SPIRAL1 at GANIL is a facility dedicated to the production of radioactive ion beams (RIBs) and their post-acceleration. A major upgrade allowed this facility to produce RIBs of condensable elements. It does so by using both a hot 1+ ion source and an ECR Charge Breeder where the latter is used to increase the ion charge state for post-acceleration. The SPIRAL1 team is pursuing R&D on both fronts in order to expand the offer of RIBs. Several 1+ sources have been or will be tested in 2023: (1) MonoNaKe, a surface ion source, is being modified to ionize short-lived lithium isotopes (2) TULIP, dedicated to ionize short lived fusion-evaporation residues has been tested online for the second time (3) the FEBIAD source has produced radioactive Cr ions for the first time. The SPIRAL1 Charge Breeder (SP1CB) is now fitted with a fixed frequency amplifier (Klystron) and a variable frequency amplifier (travelling wave tube). Using one amplifier, the other, or both, enables several heating modes, giving better control on the charge state distribution at the output of SP1CB.
Numerical simulation and experimental characterization of the TRIUMF-FEBIAD cathode temperature for optimizing the ion source performance
Authors: Maldonado Millán F , Babcock C , Day Goodacre T , Gottberg A
Published: May 2024

The FEBIAD ion source is routinely used to produce radioactive ions of halogens, molecules, and noble gases in several ISOL facilities worldwide. At TRIUMF, an extensive numerical and experimental campaign has been performed to fundamentally understand the source while improving its reliability and overall performance. Particularly, the cathode temperature has been studied by pyrometric measurements, Schottky analysis and numerical simulations to properly understand the electron emission driving the ionization. The temperature values found are consistent within the error bars and confirm the equivalence of the methodologies used. The findings can be used as part of a numerical ionization model for more realistic electron emission and the benchmarked thermal model can be used to propose novel and more robust geometries.
Enhanced Production of Multicharged Ions by Mixing Low Z Gas and Emittance Measurement on Electron Cyclotron Resonance Ion Source
Authors: Fujimura Yushi , Iwahara Kouki , Kato Yushi
Published: May 2024

We have studied to enhance efficiency of producing multicharged ions in an electron cyclotron resonance ion source (ECRIS). The gas mixing method is known as an empirical method for highly efficient production of multicharged ions. This method is to mix low Z gas into the multicharged ions plasma. There are various explanations for the gas mixing effect. One of them is the ion cooling effect. It is necessary to obtain parameters related to the ion temperature in order to experimentally confirm the effect. We measured emittances for ion beams by using a wire probe and a multi-slit. He was mixed as a low Z gas into the operating Ar gas. Charged state distributions of ion beams was measured to confirm the gas mixing effect. We have also measured emittances for the multicharged Ar ion beams and compared root mean square emittances (ε
rms) of those for pure Ar and Ar mixed by He. We confirmed that ε
rms for Ar mixed by He was lower than that for pure Ar.
Towards Tests of an RFQ Cooler and Simulations
Authors: Cavenago M. , Comunian M. , Galatà A. , Maggiore M. , Montis M. , Ruzzon A. , Cavaliere F. , Maero G. , Romé M.
Published: May 2024

The cooling of secondary beams is important for accelerator-based nuclear physics. In the radiofrequency (RF) quadrupole cooler (RFQC), RF fields and ion-gas collisions may give a considerable increase or decrease of the beam transverse emittance and energy spread, depending on a delicate tuning of heating and cooling effects, dominated by the ion beam kinetic energy and the balance of collisions and confinement forces. An extra confinement may be added by a solenoid magnetic field, as in the RFQC prototype installed in the Eltrap machine. This provides a versatile test bench (distinct from a closed accelerator installation) for detailed studies of cooling dynamics and of several RFQC technical optimizations (for gas differential pumping and bias voltages). Modeling concepts and simulation results are summarized. The major RFQC parameters are reviewed, in particular for 133Cs+ collisions against He gas whose pressure pg
ranges from 2 to 9 Pa in the reference case, with attention to the extraction, comparing triode/tetrode system, and to the bias voltages. Lower bias voltages request less pg
, but provide less cooling of the energy spread.
Characterization of a broad beam ion source converted into a high intensity deuterium beam
Authors: Podolsky V , Hepner S , Schipmann S , Valenteen S , Thompson R , Langtry R
Published: May 2024

Avalanche Energy is developing deuterium ion beams for the Orbitron fusion device. For these and similar projects, modification of off-the-shelf high current ion sources enables affordable and rapidly accessible alternatives to custom-built systems. We have successfully operated the Veeco MARK I broad beam source on deuterium to create multi-keV energy ions. Directing this beam through a small aperture required carefully designed optics. Once a narrower beam was created, a faraday cup was used to measure the beam current and profile while a Thomson Parabola was developed to help understand the beam species and energy composition.
Optimizing Ion Optical Design for Laser Ablation Source in Mass Spectrometry
Authors: Ashrafkhani Behnam , Chambers Chris , Wieser Michael , Thompson Robert , Kwiatkowski A.A.
Published: May 2024

The study focuses on optimizing a Laser Ablation Source (LAS) for use in mass spectrometry, particularly aiming to enhance transmission of ions and and determination of isotopic compositions in diverse matrices at TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN). Critical variables affecting mass spectrometer resolution, such as ion kinetic energy distribution and ion transport are optimized through LAS. The paper explores the importance of consistent initial conditions, ion transport efficiency, and ion capture for accurate and reproducible measurements. Using SIMION software, we optimized ion optical design to tackle challenges like collimating ions travelling off-axis and mass filtering. A significant part of the study is dedicated to ion optic design to enable low abundance measurement of ions of interest (e.g., 10 ions of interest out of 1014 total ions). Techniques like high voltage switching and beam shaping were explored, and the final design aims for high transport efficiency and a 4 mm effective target scan area with maximum transport efficiency. The integration of LAS with a Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) is expected to yield an analytical tool with high spatial resolution and transport efficiency for isotope abundance measurement.
Permanent magnet ECR ion source and LEBT dipole for single-ended heavy ion ToF-ERDA facility
Authors: Tarvainen Olli , Faircloth Dan , Julin Jaakko , Kalvas Taneli , Koivisto Hannu , Kosonen Sami , Toivanen Ville
Published: May 2024

We present the status of the ion source and low energy beam transport prototyping for a single-ended heavy ion time-of-flight elastic recoil detection analysis equipment. The environmentally friendly concept is based on a permanent magnet ECR ion source and dipole magnet on a 500 kV platform without SF6 insulation, producing high charge state noble gas ion beams, e.g. 3–6 MeV argon. The ion fluxes of Ar6+–Ar12+ achieved with the CUBE-ECRIS permanent magnet minimum-B quadrupole ion source exceed 1-10 particle nA required for the low energy ToF-ERDA application. The CUBE-ECRIS can produce over 1 particle nA krypton and xenon beams up to charge states Kr19+ and Xe24+, which enables extending the scope of the ToF-ERDA application. The integration of an adjustable-field permanent magnet dipole into the CUBE-ECRIS test stand at the JYFL accelerator laboratory is described briefly.
Design and implementation of high-rigidity and high-precision satellite antenna rotating unit
Authors: Wang Fengbin , Li Yuhua , Shi Guangqin , Li Guozhu , Li Xupeng , Wang Wei
Published: May 2024

The satellite antenna rotating unit is an important component that drives the satellite antenna to rotate in orbit, mainly composed of a stepper motor, harmonic reducer, and rotating transformer. This type of rotating unit has the advantages of small size, lightweight, high-rated output torque, and long rotating life. The high-stiffness and high-precision satellite antenna rotation unit is based on the existing antenna rotation unit. Through comprehensive improvement design, the measured closed-loop control has a rotation accuracy of better than 0.005°, a torsional stiffness of better than 6.5 Nm/(Å), a rotation accuracy of 6 times higher than the existing antenna rotation unit, a torsional stiffness increase of 13 times, and a rated output torque increase of 2.4 times. The article introduces the development of components, measurement of torsional stiffness, and measurement of rotational accuracy for the high-stiffness and high-precision satellite antenna rotating unit. Finally, the development conclusion is given. The successful development of a high-stiffness and high-precision satellite-borne antenna rotation unit can not only meet the precise pointing control requirements of the mechanical movable antennas and terahertz antennas of the narrow beam with a width of 0.2° but also solve practical problems such as jitter in ground testing of data transmission or relay antennas and unstable pointing of point beam antennas in orbit.
Strength limit of titanium alloy drill pipe under combined tension and torsion load
Authors: Tian Jihong , Wang Tao , Wang Xijie , Zhang Yuan , Zhang Qiang , Yu Xiaoling , Guo Shujun , Jiang Yingbin
Published: May 2024

With a focus on the issue of drill pipe failure brought on by the interaction of tension and torsion in deep and ultra-deep wells, the yield limit curve of the pipe body and joints under the combination of tension and torsion was drawn. According to the practice of DNV-RP-F201, it was investigated how temperature affected drill pipe strength. The findings demonstrate that as temperature increases, both yield and tensile strength decrease linearly, and the decreasing range gradually decreases when temperature exceeds 140°C, and yield strength decreases by 31.91% in 140°C. Under the conditions of the same yield strength and outer diameter, the larger the thickness of the drill pipe body is, the higher its tensile strength and torsional strength are. The resulting yield limit curve covers a wider range. As the temperature increases, the yield limit elliptic curves of titanium alloy drill pipes with various wall thicknesses gradually shrink. This work presents the foundation for the strength research of titanium alloy drill pipe under tension and torsion load.
Environmental test and evaluation technology of control and protection device for flexible DC converter valve
Authors: Li Dan , Luo Qin , Pan Guangze
Published: May 2024

Environmental suitability is particularly important for the safe and reliable operation of the product. The environmental test and evaluation method are studied to target the reliability requirements for the control and protection device of the flexible DC converter valve. According to the characteristics of the secondary board card of the control and protection device, a study is carried out on the mechanism of salt spray corrosion, and specific methods for implementing and evaluating the salt spray test are proposed. Using this method, a salt spray test is conducted on a secondary board card of a relay control and protection device under the finalization of the design. The test results show that this method can effectively reveal the salt spray corrosion weakness of the product. Besides, salt spray test results are also evaluated according to the corrosion conditions of the product after the test. The application of environmental test and evaluation technology of the control and protection device of the flexible DC converter valve has a significant meaning in improving the reliability of relevant products.
Evaluation of low-temperature anti-cracking and slow-release performance of salt-storage AC-13
Authors: Li Shujuan , Sun Dandan , Xu Yun , Wang Qingliang , Wang Yanmin
Published: May 2024

Asphalt mixture AC-13 was prepared using homemade salt storage additives to replace an equal volume of mineral powder. The study focused on the low-temperature anti-cracking and slow-release properties of the AC-13. The results indicate that the incorporation of salt storage additives gradually reduces the “bending tensile strength (RB
)” and “maximum bending strain (εB
)” of the AC-13. The εB
of the salt storage bituminous mixture with a replacement rate of 100% is reduced by more than 10%, but it still meets the specifications. The analysis of slow-release performance reveals that the dissolution rate of snowmelt salt in the salt storage AC-13 is uniform, with a stable precipitation amount. The slow-release effect is good and long-lasting.
A novel sensor with excellent high-temperature performance for in-situ temperature measurement
Authors: Cui Yunxian , Song Yuxin , Wang Haoyu , Wang Xiaoliang , Yin Junwei
Published: May 2024

Real-time access to critical information about system temperature variations is essential for evaluating system performance in some of the high-temperature and harsh environments. Given the technical difficulty of accurately obtaining the temperature of a high-temperature and harsh environment, a new sensor package structure is proposed. Combining ceramic sintering and isostatic pressure molding methods, the thermal junction is fixed in the temperature measurement end face of the alumina ceramic substrate, while the shell design threads play a role in fixing the sensor and preventing loosening. This paper conducted repeatability, upper-temperature limit, and high-temperature serviceability assessment tests on the sensor. The results show that the sensor maximum repeatability error is 2.4%. The sensor can continue to operate at 1200°C for more than 6 hours with no signal interruption and the upper limit of temperature measurement is 1307°C. The results demonstrate the feasibility and practicality of temperature measurement by this sensor in high-temperature and harsh environments.
Analysis of the interactive effects of scavenge parameters on spark ignition two-stroke diesel engines
Authors: Sun Tingting , Wang Shangxue , Zhang Xuesong , Zhao Chengwei , Zhang Xiaoyan , Zhu Hongru
Published: May 2024

The scavenging efficiency of a two-stroke diesel engine affects the formation of the mixture in the engine cylinder, which in turn affects the engine’s performance. A one-dimensional simulation model of a two-stroke diesel engine is established using GT-POWER, and the model with original experimental data is calibrated as boundary conditions. Firstly, the influence of crankcase compression ratio on engine performance of the two-stroke engine was investigated to obtain an appropriate crankcase compression ratio; Then, based on the optimization index of scavenging efficiency, the optimal combination of engine air port structure and timing is obtained through orthogonal optimization calculation method. To achieve higher scavenging efficiency, when the phase of the air port remains unchanged, a scavenging port width ratio of 1.0 and an exhaust port width ratio of 0.8 can achieve a scavenging efficiency of 97.2%; When the air port size remains unchanged, the engine scavenging efficiency reaches 96.44% when the scavenging port timing is 123° CA and the exhaust port timing is 89° CA.
Numerical simulation of efficient welding for thick plates in shipbuilding using simufact welding
Authors: Bin Wei , Liu Zhijian , Xu Minyi , Hong Yuming , Zhu Diyu
Published: May 2024

In the welding process of medium-thick plates, it is common to create grooves and perform double-sided multi-pass welding. However, this approach leads to low welding efficiency and high costs. Hence, this study utilizes a groove-free, double-sided double-pass welding method to enhance welding efficiency and decrease shipbuilding expenses. A finite element model of groove-free submerged arc welding for medium-thick plates was established using SolidWorks software, and mesh division was carried out. Subsequently, numerical simulations of high-voltage, high-current double-sided double-pass submerged arc welding for medium-thick plates were conducted using Simufact Welding software. In the simulation, a mobile double ellipsoid heat source was utilized to replicate the dynamic alterations throughout the entire welding process. Subsequently, the temperature field of the welded material was computed. Finally, utilizing the temperature field results, the residual stress distribution within the welded material was computed through the thermal-structural coupling feature. The simulation results revealed a significant temperature gradient at the center of the heat source during the welding process, with a slower temperature change observed behind the heat source. Around 4000 seconds, the weldment cooled to room temperature. At this point, the thermal stress mainly concentrated around the weld seam. This numerical welding simulation serves as a crucial reference for designing welding process parameters and researching residual stress distribution. Consequently, it enhances welding efficiency in the field of shipbuilding.
Effect of heat treatment on microstructure and cavitation resistance of multi-dimensional WC-10Co4Cr coating
Authors: Wu Kunze , Yang Changchun , Li Ruiqi , Ding Xiang
Published: May 2024

The multi-dimensional WC-10Co4Cr coating was prepared on 316 stainless steel by using HVOF spraying, and the impact of heat treatment temperature on the microstructure, cavitation resistance, and mechanical properties of the multi-dimensional WC-10Co4Cr coating was studied. Heat treatment at higher temperatures leads to lower porosity and upper hardness of the coating. Meanwhile, oxidation products such as CoWO4 and Cr2O3 were produced at 500°C. The coating has the best anti-cavitation performance after heat treatment at 300°C.
Microstructure and properties of laser-melted FeCoCrNiSiMox high-entropy alloy coatings
Authors: Ma Yiheng , Deng Shouliang , Wang Ye , Li Zehua , Gong Xun , Zhao Hui , Chen Haojie , Li Mei
Published: May 2024

In this research, FeCoCrNiSiMox high-entropy alloy coatings were created using laser cladding technology on 45 steel surfaces in order to provide a coating with high hardness and strong abrasion resistance. The present study aims to evaluate the effects of including Mo elements on the tissue, structure, and mechanical characteristics of FeCoCrNiSiMox high mercury alloy coatings under optimal laser melting process conditions. Through the regulation of Mo element incorporation, it has been observed that for values of x less than or equal to 0.2, the coating exhibits a singular FCC structure. However, for values of x greater than 0.2, a phase transition occurs in the coating’s structure, resulting in the appearance of a second phase. Consequently, the alloy primarily comprises a solid solution phase combined with the FCC phase and the Mo-rich phase. The introduction of the Mo element results in a steady reduction in the microstructure of the coating, which predominantly consists of dendritic structures. Additionally, the average hardness of the coating exhibits an increase, accompanied by an enhancement in its wear resistance.
Research on stress corrosion cracking behavior of stainless steel bellows expansion joints used in GIS equipment
Authors: Wang Jun , Cao Xianhui , Chen Junjun , Zou Jincheng , Liu Weike , Huang Rong
Published: May 2024

This article conducts metallographic structure, martensite content, Vickers hardness, and stress corrosion performance tests on two commonly used stainless steel bellows expansion joints with different materials and geometric parameters in the power grid. The material properties and stress corrosion sensitivity of 304 and 316 stainless steel bellows are compared. The results indicate that the martensite content is highest at the peak position and lowest at the trough position in the bellows. As the curvature radius of the bellows decreases, the martensite content increases at the same position. Under the same conditions, the content of deformed martensite in 304 stainless steel is much higher than that in 316 stainless steel. After soaking in boiling MgCl2 solution for 7 days, the stress corrosion crack length of 304 stainless steel bellows is greater than that of 316 stainless steel. As the curvature radius of the ripple decreases, the crack length of 304 stainless steel bellows increases from 1.38 mm to 11.39 mm, while the crack length of 316 stainless steel bellows only increases from 0.32 mm to 7.32 mm.
Study on properties of diamond-like carbon coatings based on COMSOL
Authors: Yu Zeyang , Guo Jing , Guo Zhaoxin , Yu Xiaoming
Published: May 2024

Comsol software was used to design and simulate the preparation of DLC coating on 316 stainless steel substrate by vacuum evaporation plating method. The influence of evaporation temperature on coating quality was explored by controlling substrate temperature factors, and the corrosion resistance of DLC was simulated. The simulation coating preparation results showed the surface distribution of the DLC coating prepared by vacuum evaporation is uneven, and the thickest core becomes thinner layer by layer along the periphery. Under the same conditions, the higher the evaporation temperature is, the better the coating quality is. The corrosion behavior of DLC coating over time was studied by simulating the corrosion of DLC coating in the human body environment. The simulation corrosion results showed that the corrosion rate of DLC coating in the human body environment was slow, and the corrosion rate of the metal matrix was significantly higher than that of DLC coating.
Optimal estimation of pure states with displaced-null measurements
Authors: Girotti Federico , Godley Alfred , Guţă Mădălin
Published: May 2024

We revisit the problem of estimating an unknown parameter of a pure quantum state, and investigate ‘null-measurement’ strategies in which the experimenter aims to measure in a basis that contains a vector close to the true system state. Such strategies are known to approach the quantum Fisher information for models where the quantum Cramér-Rao bound (QCRB) is achievable but a detailed adaptive strategy for achieving the bound in the multi-copy setting has been lacking. We first show that the following naive null-measurement implementation fails to attain even the standard estimation scaling: estimate the parameter on a small sub-sample, and apply the null-measurement corresponding to the estimated value on the rest of the systems. This is due to non-identifiability issues specific to null-measurements, which arise when the true and reference parameters are close to each other. To avoid this, we propose the alternative displaced-null measurement strategy in which the reference parameter is altered by a small amount which is sufficient to ensure parameter identifiability. We use this strategy to devise asymptotically optimal measurements for models where the QCRB is achievable. More generally, we extend the method to arbitrary multi-parameter models and prove the asymptotic achievability of the the Holevo bound. An important tool in our analysis is the theory of quantum local asymptotic normality which provides a clear intuition about the design of the proposed estimators, and shows that they have asymptotically normal distributions.