bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the effect of biased surfaces in the vicinity of the large extraction area of the ELISE test facility
Authors: Yordanov D , Wunderlich D , Wimmer C , Fantz U 
Published: April 2022

Abstract
The ion source at the ELISE test facility is an intermediate step towards the operation of the ITER NBI source and it demonstrated fulfillment of the ITER NBI requirements for accelerated negative current density in hydrogen. However, in deuterium operation the co-extracted electron current density (je) is higher and much more unstable and limits the source performance. In the standard setup of ELISE, je is reduced by a positive potential applied to the plasma grid (PG) with respect to the source body and the bias plate (BP). To further reduce and stabilize je in deuterium, an alternative scheme by biasing the BP is investigated. Measurements of the BP currents and of the extracted currents, combined with probe diagnostics in the vicinity of the PG for short-pulse in deuterium operation are presented. Biasing the BP, leads to a change in the distribution of the plasma potential in front of the extraction area, affecting the charged particle fluxes towards the BP and the PG and a strong reduction of je.
Techniques to widen the operational space of SPIDER Radio Frequency driven plasma source
Authors: Casagrande R , Dan M , Maistrello A 
Published: April 2022

AbstractSPIDER is the full-size prototype of the ion source of the ITER Neutral Beam Injectors, and is in operation since June 2018 as part of the ITER Neutral Beam Test Facility. The ion source is composed of 8 Radio Frequency drivers supplied by 4 RF oscillators, rated for operation at 1 MHz, for a total power of 800kW. This article presents a strategy for the selection of source biasing and of operating frequencies of the different RF generators to facilitate plasma initiation and to improve plasma stability. This operational strategy improved the plant reliability at high RF power in a broader range of operational conditions in SPIDER.
A 2D semi-analytical electromagnetic model for cylindrical ICP sources with Faraday shield
Authors: Chen P , Yang J , Zhou L , Zuo C , Li D , Chen D 
Published: April 2022

Abstract
Faraday shield(FS) is a metallic shield with slits through which electromagnetic energy is coupled into cylindrical ICP sources. Thus, the effect of FS on the RF field and power coupling is important. A 2D semi-analytical electromagnetic model considering both FS and plasma is proposed. The results compared to a 2D numerical model shows that the semi-analytical model is available in electromagnetic field calculations. It is found that both FS and plasma have no influence on the magnetic field outside them. FS strengthens the electric field around the slits and weakens the electric field around the middle of the stripes, and this effect is due to the gradient field generated by the electric charge accumulated on the FS surfaces. From the point of view of the pure 2D electromagnetic field, FS affects the electric field distribution in a small region, and it seems to not affect the total power coupling into plasma.
Study of the charged particle flow near the plasma grid in negative ion source
Authors: Masaki S. , Nakano H. , Rattanawongnara E. , Nagaoka K. , Ikeda K. , Fujiwara Y. , Osakabe M. , Wada M. , Tsumori K. 
Published: April 2022

Abstract
Flows of the charged particles in hydrogen (H) and deuterium (D) plasmas were measured with the single-tip directional Langmuir probe. The flow patterns of positive and negative ions have been constructed from the data by moving the probe near the plasma grid. The positive ion flow from driver to extraction regions showed the different velocity equivalent to the mass difference between H and D. The negative ion flow indicated the surface production of negative ions on the plasma grid, and changed the direction corresponding to the magnitude of the extraction electric field.
Recent developments and results of the LPSC PHOENIX type ECR charge breeder
Authors: Angot J , Baylac M , Luntinen M , Migliore M , Tarvainen O , Thuillier T 
Published: April 2022

Abstract
Four models of the PHOENIX ECR charge breeder have been manufactured for ISOL application. Two are currently under operation at TRIUMF (ISAC) and GANIL (SPIRAL 1) while the SPES one is being installed on the facility. The last model is set on the LPSC 1+N+ test bench where a R&D program is ongoing to improve its performances. The last modifications consisted in improving the beam line vacuum and the alignment. Commissioning experiments showed an improvement of the charge breeder performances for all the tested species. The global CB efficiency is close to 100% for Cs when correcting the measurements with the beam transmission. Na and K efficiencies have increased significantly to reach 18.7% for Na8+ and 22.7% for K9+. In parallel, the charge breeder plasma was studied injecting short pulses of 1+ ions and using a zero-dimension model to estimate the plasma parameters. These experiments have provided a better understanding of the performance improvement. The last developments of the LPSC Charge Breeder together with the experimental results are presented.
Improvement of the Efficiency and Beam Quality of the TRIUMF Charge State Booster
Authors: Adegun J , Ames F , Kester O 
Published: April 2022

Abstract
An Electron Cyclotron Resonance Ion Source is used as the charge state booster (CSB) at the Isotope Separator and Accelerator facility (ISAC) of TRIUMF. Since its commissioning in 2010, the source has been used to charge breed radioactive ions ranging from potassium to erbium operating in single-frequency heating mode. Under this regime, the single charge state efficiency of the booster was measured up to 6 % for noble gases and the maximum charge state of Cesium that can be measured is 27+. The rf system of the source was recently upgraded to implement the two-frequency heating using a single waveguide. Preliminary operation of the booster in a two-frequency heating mode shifted the maximum charge state of Cesium that can be measured to 30+. Another point of improvement that is being addressed is the beam extraction system of the booster. A quadrupole scan technique using a thick lens approach has been developed to measure the emittance of the extracted beam and to analyze the quality of the extraction system. Overall, the system of the CSB is currently being optimized in preparation for the detailed determination of the effect of the two-frequency heating on the beam output.
High-voltage breakdown in the injection-extraction region of the CANREB EBIS: A possible mechanism
Authors: Charles Chris R.J. , Cavenaile Mathieu , Harford Paige , Ames Friedhelm , Schultz Brad , Kester Oliver 
Published: April 2022

Abstract
OmniTrak simulations were performed in the 40°K injection-extraction region near the collector trumpet of the CANREB EBIS to understand the nature of chronic electrical breakdowns of PEEK feedthroughs. These feedthroughs are designed to route high-voltage wires (up to +15 kV) from room temperature to each drift-tube at 4°K, while operating in the strong superconducting semi-Helmholtz field. The electric field strength |E| at the PEEK feedthroughs are ∼ 7 × 105 V/m within about 2-3 mm of the surroundings at ground potential. When simulating only bare wires (with no PEEK feedthroughs), |E| increases by about 1 order-of-magnitude to > 106 V/m in the same region. Assuming a 3 Tesla magnetic field, electrons starting with 0 eV near the PEEK feedthroughs undergo helical motions due to

E
→

×

B
→

-drift and demonstrate reflections from magnetic mirror effects. A combination of this helical motion, reflecting mirror trajectories, and attraction of electrons to exposed HV wires may be responsible for the ongoing HV breakdown of insulating feedthroughs in this region of the EBIS. Solving this problem requires complete ground-shielding of all HV wiring to eliminate |E| and should encapsulate all wires to prevent breakdown paths.
Non-destructive beam spatial profile measurement using a gas sheet monitor for a high-intensity ion beam
Authors: Yamada I , Wada M , Kamiya J , Kinsho M 
Published: April 2022

Abstract
A non-destructive beam spatial profile monitor system using a gas sheet has been developed. The 4 mm thick gas sheet of over 40 mm width enables increase of the local gas pressure high enough to record a two-dimensional beam profile. A CCD camera coupled to an image intensifier detects photons produced by beam-gas interaction with the signal intensity that makes the time evolution study of the beam possible. We demonstrated that the J-PARC 3MeV, 60 mA H- beam profile which is measured with intensity error of 8.4-12% and spatial resolution of 1 mm changed depending on the controls of the acceleration cavity in the beam pules of 50 μs.
Extraction and low energy beam transport models used for the IFMIF/EVEDA RFQ commissioning
Authors: Bellan L. , Akagi T. , Bolzon B. , Cara P. , Carin Y. , Cavenago M. , Chauvin N. , Comunian M. , Dzitko H. , Fagotti E. , Grespan F. , Kondo K. , Moya I. , Pisent A. , Podadera I. , Scantamburlo F. , Sugimoto M. 
Published: April 2022

Abstract
The Linear IFMIF Prototype Accelerator (LIPAc) is a high intensity D+ linear accelerator; demonstrator of the International Fusion Material Irradiation Facility (IFMIF). In summer 2019 the IFMIF/EVEDA Radio Frequency Quadrupole (RFQ) accelerated its nominal 125 mA deuteron (D+) beam current up to 5 MeV, with 90% transmission for pulses of 1 ms at 1 Hz. This success was possible thanks to an intense previous campaign of modelization and measurements in order to characterize the RFQ input beam, which is affected by the ECR ion source extraction and the low energy beam transport. The simulation models used with the measurement benchmarks are here presented.
Mass distributions of ions extracted from target cavity confined plasmas produced by nanosecond laser pulses
Authors: Hernandez J E , Wada M 
Published: April 2022

Abstract
Ion and electron current signals produced from a solid graphite target under 1064 nm nanosecond laser pulse irradiation were investigated. A cavity is formed by laser incidence at the center of the target surface at 10 Hz repetition rate while being rotated along its axis. Ion mass distributions were recorded via a time-of-flight spectrum coupled with a detector assembly attached along the propagation axis. Peak shifts towards slower times were observed for increasing number of pulses. The effect of magnetic detection on the ion current signals is investigated, and showed significant peak shifts for 20 GW/cm
2 laser power density.
Effects of axial magnetic field in a magnetic multipole line cusp ion source
Authors: Rawat Bharat Singh , Sharma S K , Choksi B , Bharathi P , Sridhar B , Gupta L N , Thakkar D , Parmar S L , Prahlad V , Baruah U K 
Published: April 2022

Abstract
Experiments have been performed to study the effects of axial magnetic field on plasma and ion beam parameters in a magnetic multipole line cusp ion source. Studies performed on ring cusp and Kaufmann type ion sources suggest that the axial component of magnetic field may help in improving the ion extraction current at a low discharge power. The line cusps ion sources have been used since long to produced uniform beams, however, they lack axial component of the magnetic field. These ion sources generally suffer from low efficiency possibly due the absence of axial magnetic field. In this work, an additional magnetic coil is added at various axial positions between the back-plate and the plasma grid of the multipole line cusp ion source. We have investigated the effects of axial magnetic field on the discharge efficiency and source parameters like beam current and uniformity in the multipole line cusp ion source. The beam profiles are obtained using an eleven-channel faraday cup array to estimate the effects of the axial magnetic field on beam uniformity and divergence. Initial studies suggest a reduction of beam divergence with increasing axial magnetic field. A significant rise in the beam current and the discharge current is also observed when the axial magnetic field is increased. Particle trajectory simulation using the CST-Studio suite is utilised in understanding the role of confinement of primary electrons behind the improved performance of the ion source.
Studies of bremsstrahlung and characteristic X-Ray lines using the VENUS ECR
Authors: Benitez Janilee , Todd Damon , Xie Daniel 
Published: April 2022

AbstractThough known for their production of high currents of highly-charged ion beams, advanced electron cyclotron resonance (ECR) ion sources like VENUS at Lawrence Berkeley National Laboratory (LBNL) also generate significant numbers of x-rays. The LBNL ECR ion source group has spent many years studying the x-rays emitted from VENUS in order to gain a better understanding of the ECR plasma. Based on the emitted bremsstrahlung continuum, a spectral temperature Tscan be calculated which is a relative indication of the temperature of the plasma electrons. We will present correlations between Ts with respect to parameters such as magnetic fields. In addition to the bremsstrahlung continuum, the plasma ions emit characteristic x-rays. We will show that additional information can be gained by investigating spectral line shifts. A summary of this recent research using VENUS will be presented and discussed.
Design and simulations for a Penning Ion Trap Source for the CHIP-TRAP Mass Spectrometer
Authors: Horana Gamage M. , Bhandari R. , Gamage N. D. , Keblbeck D. , Redshaw M. 
Published: April 2022

Abstract
At Central Michigan University (CMU) we have been developing the CMU High Precision Penning Trap (CHIP-TRAP) mass spectrometer for precise mass measurements on stable and long-lived radioactive isotopes. As part of this apparatus, we have designed a Penning Ion Trap (PIT) source to produce singly-charged, low intensity (∼100s to 1000s of ions in ∼1 μs duration) ion pulses from gaseous samples. The PIT source is similar to a PIG type source, composed of an electric field superimposed on a magnetic field. The electric field is produced by a cylindrical Penning trap structure consisting of two end caps and a center ring with a trap volume of about 0.8 cm3. The trap structure is housed inside a permanent neodymium ring magnet bore. Gas is inserted into the trapping region and ionized by an ∼1 μA electron beam from a thermal emitter. Ions are extracted from the PIT source by lowering the voltage on one of the end caps. They are then accelerated into the beam line. In this paper, we report on the design of the PIT source and simulations to investigate and characterize the expected beam properties.
Duoplasmatron type molecular carbon ion source
Authors: Wada M , Aki H , Miyamoto N 
Published: April 2022

Abstract
An ion source capable of producing molecular ions delivers a beam of impurity dopant for shallow ion implantation of semiconductor device fabrication. Production and transport of low energy molecular ions is indispensable for tabulating fundamental data on plasma-wall interactions that should be used to design a future nuclear fusion reactor. An ion source plasma can produce molecular ions of solid materials by sputtering, while low temperature plasma efficiently transports produced molecular ions to the source extraction hole. A duoplasmatron ion source with the carbon plasma electrode has successfully produced poly-atomic carbon ions up to C6
+. The intermediate electrode has six holes to guide cathode plasma to the carbon anode performing as the plasma electrode. A 1 mm diameter extraction hole is opened at the center of the carbon plasma electrode, where is no direct exposure to the plasma from the cathode region. The ion source maintains a stable discharge with both H2 and Ar as discharge support gas, but works better at lower pressure with Ar. A hydrogen plasma produced molecular ions of hydrocarbons with the mass separated current of C3H5
+ with the intensity comparable to other ion species including atomic, diatomic and triatomic hydrogen ions.
Laser ion source for semiconductor applications
Authors: Kulevoy T V , Losev A A , Alekseev P N , Satov Yu A , Shumshurov A V , Lagov P B , Letovaltseva M E , Zinoviev S A 
Published: April 2022

Abstract
Carbon implantation can be effectively used for axial minority charge carriers’ lifetime control in various silicon bulk and epitaxial planar structures. When carbon is implanted, more stable recombination centres are formed and silicon is not doped with additional impurities, as for example, when irradiated with protons or helium ions. Economically, such a process competes with alternative methods, and is more efficient for obtaining small lifetimes (several nanoseconds). I-3 ion injector with laser-plasma ion source at Institute for theoretical and experimental physics (ITEP) is used as ion implanter in semiconductors. The ion source uses pulsed CO2 laser setup with radiation-flux density of 1011 W/cm2 at target surface. The ion source produces beams of various ions from solid targets. The generated ion beam is accelerated in the two gap RF resonator at voltage of up to 2 MV per gap. Resulting beam energy is up to 4 MV per charge. Parameters of carbon ion beam generated and used for semiconductor samples irradiation during experiments for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures are presented.
Suppression of damages on cathodes in the negative hydrogen ion source for the stable NBI system
Authors: Shimabukuro Y , Hiratsuka J , Ichikawa M , Murayama M , Saquilayan G , Kisaki M , Kojima A , Tobari H , Kashiwagi M 
Published: April 2022

Abstract
A protection system of ion source components from local abnormal discharge has been developed with ITER-class filament-driven negative ion source for high power and stable long-term operation. Protection from unpredictable discharge is a common issue for filament and RF-driven ion sources. To understand how fast should be cut off the discharge, threshold energy not to cause critical damage on the filament was investigated. The experimental exploration concluded that the energy less than 1.87 J or fast cut-off faster than 343 μs is the threshold for the robust protection of the filaments. A developed system successfully detected and cut off the discharge at 100 μs under noisy environments with the high current power supply. Moreover, the detection system is remotely adjustable. Such versatile protection system can contribute to any abnormal discharges in high current system including various ion sources, gyrotron, and high voltage components.
Development of ECR ion source with high-temperature superconducting REBCO coils
Authors: Chong T H , Fukuda M , Yorita T , Kanda H , Yasuda Y , Koay H W , Morita Y , Takeda K , Hara T , Hisamatsu M , Zhao H , Ishiyama A , Noguchi S , Ueda H , Fukui S , Matsubara Y , Mikami Y , Takahashi N , Yoshida J , Hirayama T , Nagaya S , Watanabe T 
Published: April 2022

Abstract
A new High-Temperature Superconducting ECR (HTS-ECR) ion source is under development in Research Center for Nuclear Physics (RCNP), Osaka University. This ion source will be used for production of high intensity proton, deuteron and He ion beams. The HTS-ECR magnets are composed of three solenoid coils and a set of sextupole coils made of REBCO tapes, a high-temperature superconductor. The HTS-ECR ion source is designed to operate at frequency of 2.45 GHz and 10 GHz. Performance test of the HTS coils had been carried out at 31 K and 77 K. This HTS coil technology will be applied to development of a meter-size HTS coil system of a high intensity compact AVF cyclotron. This paper introduces the basic design of the HTS-ECR ion source. The performance test results showed that REBCO solenoids remain superconducting state with a current up to 400 A. Simulation results of the magnetic field and electromagnetic field distributions in a plasma chamber fulfilled the requirements of electron cyclotron resonance conditions at 2.45 GHz and 10 GHz. Simulation result of mirror ratios and electromagnetic field amplitudes are also presented in this paper.
First injector commissioning results with helium beam at MedAustron Ion Therapy Center
Authors: Gambino Nadia , Kausel Matthias , Guidoboni Greta , Penescu Liviu , Rizzoglio Valeria , Schmitzer Claus , Kurfürst Christoph 
Published: April 2022

Abstract
MedAustron is a synchrotron-based Particle Therapy Accelerator located in lower Austria which delivers clinical proton and carbon beams in the range of 62-252.7 MeV/u and 120-400 MeV/u respectively in two clinical treatment rooms. A proton Gantry was recently commissioned in a third clinical treatment room and a fourth experimental beamline is dedicated to non-clinical research activities. Within the latter, the injector commissioning has recently started for He2+ beam generation. The long-term goal is to use helium for cancer treatment due to its favourable physical and biological properties. The helium beam properties from the source up to injection further downstream into the accelerator, i.e. from the Low Energy Beam Transfer line to the Linear Accelerator are discussed in terms of beam emittance, intensity and transmission efficiency. Furthermore, a comparison with simulated data is presented.
Load Allocation of Biomass Cogeneration Units Based on Multi-objective Optimization Algorithm
Authors: Xiao Ying , Wang Yufang 
Published: April 2022

Abstract
The optimal allocation of biomass thermoelectric loads is a multi-objective, multi-constrained optimisation mathematical model based on the biomass fuel consumption and environmental performance of the unit. The thermoelectric loads are allocated rationally between operating units to minimise the total biomass fuel consumption overall, subject to the constraints of meeting user requirements and unit operating times. The multi-objective optimisation algorithm was used to investigate the optimal allocation of the material thermoelectric load. The calculation results show that the method is simple and convenient and can reasonably allocate the heating load and power generation load of each unit, effectively reducing the overall biomass energy consumption and thus achieving energy saving.
Numerical Simulation Research of Excavation Based Enhanced Geothermal System
Authors: Li Yu , Ma Ke , Li Hong , Tao Ye , Liu Guoyang 
Published: April 2022

Abstract
Under the premise that the global fossil energy is decreasing, geothermal energy has entered the public view with its huge reserves. Geothermal energy can supply energy stably and uninterruptedly without being restricted by factors such as seasons climates, sunlight changes, and has broad development potential. This paper introduces a new deep geothermal development model—Excavation Based Enhanced Geothermal System (EGS-E). The innovative excavation based EGS-E scheme uses mining techniques to form deep underground access for creating artificial heat reservoir with multi-level fracture networks using excavation, blasting, and caving. The working water enters the heat exchange pool through the shaft for heat exchange. Different from the traditional geothermal model, this model can form an ultra-large volume, high permeability heat source and stable heat storage due to its special structure. In this study, a steady-state 3D model was established to study the heat exchange, temperature at the water outlet, and pressure distribution at the central section of the excavation based enhanced geothermal system (EGS-E). The results show that: when the inlet fluid velocity increases from static to 100m/s, the average outlet fluid temperature decreases from 473.15K to 360K. The heat production is better than that of EGS-D, and it is an ideal alternative to the existing EGS