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The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C4+ ions; its performance such as beam intensity and stability has already reached the medical requirements. Therefore, the prototype development of the source for medical use is essentially finished. Recently, we have started a few studies on other applications of the source. One is the production of fullerenes in the ECR plasma and modified fullerenes with various atoms for new materials. A second application is the production of multiply charged ions (not only carbon) for ion implantation. In this paper, some basic experiments for these applications are reported. [ABSTRACT FROM AUTHOR]

The nonlinear mechanisms governing the interactions between whistler or lower hybrid waves and loss-cone type particles’ distributions in magnetized plasmas are of great importance if one considers the major role that waves of frequency below the electron cyclotron frequency play in space and thermonuclear fusion plasmas. Up to now, most of the numerical simulations have been devoted to study the nonlinear processes at work when the plasma is weakly relativistic and when the anisotropy of the particles’ distributions leads to the so-called maser instability. However, in many interesting cases, the particles’ energies are sufficiently weak to ensure the validity of the nonrelativistic approximation. In this framework, the paper studies the interaction at normal cyclotron resonances between lower hybrid waves and electron distributions presenting loss-cone like features. A theoretical Hamiltonian model and a corresponding numerical symplectic code are used to evidence and to explain the nonlinear mechanisms at work at the saturation stage of the loss-cone instability. Moreover, simple analytical expressions and scaling laws have been derived for the linear growth rates and the wave amplitude at saturation. [ABSTRACT FROM AUTHOR]

A kinetic theory model for the absorption of high-frequency guided plasma waves is presented for a warm, inhomogeneous, magnetized plasma column loaded inside a waveguide. Electron cyclotron resonance (ECR) absorption and Landau damping terms, derived as the anti-Hermitian part of the susceptibility tensor, are included in the model for a loss-free plasma-loaded waveguide developed earlier [A. Ganguli et al., Phys. Plasmas 5, 1178, (1998)]. In this formulation, the imaginary part of the complex propagation constant (in the presence of absorption) is obtained using a perturbation technique treating the anti-Hermitian part of the dielectric tensor as small in comparison to the Hermitian part, for the loss-free plasma. In this paper, we present the formulation for the inclusion of ECR absorption and Landau damping along with numerical results describing the role of a small population of warm electrons in wave damping in such a discharge. Numerical results are presented in the form of dispersion curves (plots of Vphase versus ω/Ωe) and damping curves (plots of |Im kz/kv| versus ω/Ωe). It is seen that although the warm electrons have a marginal effect on wave dispersion, their presence produces a marked increase in the damping rates away from the ECR region. It is also shown that damping occurs primarily through Doppler-shifted ECR resonance and not Landau damping, even well away from ECR. Power absorption calculations are also presented for two magnetic field profiles. [ABSTRACT FROM AUTHOR]

The high temperature superconducting (HTS) floating magnet of the Ring Trap 1 (RT-1) reached the first experiment on levitation and plasma. The magnet using an HTS coil was levitated stably by levitation coil, and plasma was produced around the ring-shaped HTS magnet by electron cyclotron heating with 8.2 GHz microwave. This novel plasma device was constructed at the University of Tokyo to explore means of achieving the advanced-fuel fusion. The plasma confinement mechanism is based on the concept of high-beta relaxed state that is self-organized within flowing plasma. The HTS magnet is operated in a persistent-current mode and magnetically levitated in a plasma vacuum chamber. The weight of the HTS magnet is about 110 kg. Initially the HTS coil is cooled below 20 K by an external cooling system with detachable transfer tubes. After the transfer tubes are detached, an experiment of levitation and plasma is conducted while the HTS coil temperature remains within the range of 20 K-32 K without cooling. This paper describes the HTS coil design and test results of the HTS magnet as follows; an initial cooling, a persistent-current operation without cooling and the first levitation and the first plasma experiment. [ABSTRACT FROM AUTHOR]

In this paper, the electron-cyclotron resonance (ECR) mechanism of electrons heating by electromagnetic wave in ECR microwave low-pressure plasma reactors is considered. In such reactors, ionization is mainly provided by fast electrons trapped by multipolar magnetic system. A particle simulation is carried out for statistical ensemble of electrons in magnetic systems of different configurations with taking into account previous experimental results. The escape of fast electrons from the magnetic traps to the walls is identified as the major factor behind the loss of electrons in the limit of a collisionless plasma. A comparative evaluation of different multipolar magnetic systems is made. Basic requirements are set out concerning the optimal design of multipolar ECR plasma reactors. Several approaches for providing the efficient ECR heating of electrons are proposed. [ABSTRACT FROM AUTHOR]

Laser ion sources (LIS) are capable of delivering short pulses of highly charged ions of almost any element, with high intensity. In this paper, the basic processes of the laser interaction with plasma generated from a solid target will be discussed. The application of the laser-plasma theory will be applied to the subsystems of the LIS, and some examples of ion beam properties given, with a more detailed description of the implementation of a LIS at ITEP, Moscow. Finally the parameters for a LIS for high-current, low charge-state, long pulse operation will be discussed, along with transverse magnetic confinement, and the possibilities for injecting a laser plasma into an electron cyclotron resonance ion source. [ABSTRACT FROM AUTHOR]

There is a clear evidence that the combination of ability to produce intense beams of highly charged heavy ions and of reliability, stability and low emittance can be guaranteed only by an adequate design of electron cyclotron resonance ion sources (ECRIS). Following the roadmap defined by Geller's scaling laws (1987) and the high B-mode concept (1990), the evolution of ECRIS has been steady and it amounted to about one order of magnitude per decade, as for high charge state currents. A further increase is possible according to the standard model of ECR sources unless technological problems may limit it in the future. Some sources are in the commissioning or construction phase to get the milliampere level for highly charged heavy ions, and some limitations have been already found but the possibility to get a further step forward remains unchanged. This paper presents the flashbacks of previous relevant experiences, along with the perspectives for higher current production in the years after 2010. [ABSTRACT FROM AUTHOR]

Electron Bernstein wave (EBW) generation via mode conversion is observed in a short cylindrical electron cyclotron resonance (ECR) plasma system. ECR plasma with input microwave power varying from 160 to 800 W is produced at an operating pressure of 10-3 mbar with hydrogen gas with a maximum plasma density of 3.1×1010 cm-3 at the center and plasma temperature of 10 eV. The axial magnetic field required for ECR in the system is produced by two identical magnetic coils arranged in the Helmholtz configuration. The fundamental ECR surface (B=875 G) is located at the geometrical center of the plasma system. Microwaves of 2.45±0.02 GHz from a magnetron in TE10 mode are launched radially to have extraordinary (X) wave in plasma. The EBW is observed to be generated at the upper hybrid resonance layer at a distance of 2 cm from the center towards the microwave source. The EBW is assumed to be generated through X-B mode conversion which is inferred by the observation of the parametric decay of the incident wave. The experimental results pertaining to the EBW detection and characterization are discussed in this paper. [ABSTRACT FROM AUTHOR]

The use of superconducting magnets in ECR ion sources has the potential for large power savings compared with resistive magnets. High temperature superconductors (HTS) offer further advantages including compactness, efficiency, and a simplification of the overall system. Space Cryomagnetics Ltd has designed and manufactured a pair of HTS magnets for an ion source for Pantechnik. In this paper we describe the design, manufacture, and test results of these magnets. [ABSTRACT FROM AUTHOR]

This paper summarizes recent research activities on materials processing using millimeter-waves in Japan with emphasis on the work performed at the Joining and Welding Research Institute (JWRI), Osaka University. Extensive research results conducted at the JWRI on ceramics sintering and modification of thin film properties with millimeter-wave radiation from a 28-GHz gyrotron are described. In the sintering of pure Al[SUB2]O[SUB3], it was found that al a similar density and grain size a big difference in the bending strength appeared in the sample after millimeter-wave sintering as compared with that after conventional sintering. This result was attributed to come from the difference in the grain boundary structures due to the unique millimeter-wave effect. We have also obtained highly dense sintered Si[SUB3]N[SUB4] and Aluminum Nitride (AIN) by the millimeter-wave method with new sintering aids containing Yb[SUB2]O[SUB3] at a temperature lower by about 200 °C-400°C than that by ibc conventional method. It was verified that selective heating of b[SUB2]O[SUB3] by millimeter-waves around the grain boundary promoted a densification process in its liquid phase. A high thermal conductivity of 210 W/m °C could he obtained in AIN samples sintered at 1700°C for 180 mtn in N[SUB2]+ 3% H[SUB2] gas environment. In the research of thin-film modification the millimeter-wave irradiation to Strip[SUB3] films prepared by mirror-confinement-type electron cyclotron resonance (MCECR) plasma sputtering method could drastically improve their crystallinity and electrical properties at remarkably lower temperatures than by the conventional thermal methods. The crystallization temperature of amorphous films on Si substrates were 300°C and the dielectric constant reached to about 260. [ABSTRACT FROM AUTHOR]

Electron cyclotron resonance ion sources (ECRIS) are sophisticated plasma devices, with a complex magnetic structure. The designer of an ECRIS usually solves the following problems: (i) the conception of an efficient magnetic structure; (ii) the design of an efficient extraction system. To solve the first problem numerical codes are either free or commercially available; we briefly summarize the characteristics of these codes, with particular emphasis on cryogenic devices. The second problem is much more tricky, since it is not only an electrostatic problem, as it also involves the plasma. Different codes are, however, able to treat the problem, with some assumptions concerning the plasma; these assumptions are discussed. These codes can be very useful for the new ECRIS generation, where the current densities become very high. But today there is no program available for the calculation of the charge state distribution of the ions, the magnetic structure being given; only the experience of the designer and a certain knowledge of conception rules can lead to some (rough) estimate of the future performances. We present in this paper the first version of such a code, where the input parameters of the code are the technological parameters. These inputs being given, the code solves the self-consistent problem of the plasma creation (through the resonant interaction of the electrons with the wave), the production of the ions and their transport to the extraction zone. The first results of this code are presented and discussed. This article shows that it will be soon possible to have reliable predictions of the performances of an ECRIS. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Featured Application: We provide a microwave system design that is much smaller than the conventional design, and provide a method for judging whether the size of the discharge chamber is better under the condition of a limited permanent magnetic ring. This is of reference value for workers with similar design requirements. The Electron Cyclotron Resonance (ECR) ion source fulfills high-current, high-efficiency, and compactness requirements for high-voltage proton accelerators. It is a cathode-free source that uses microwaves to heat a magnetically confined plasma, so there is no cathode loss resulting in a short service life. We finished the design for a miniaturization ECR ion source system, including a microwave system and source body. The traditional microwave system's scale, which is approximately 1 m, has been reduced to 0.234 m, and the transmission efficiency is greater than 90%. The influence of cavity size and magnetic field distribution on gas ionization is analyzed under the condition that the outer size of the permanent magnet ring is limited, and the optimal scheme of cavity size and saddle-shaped magnetic field distribution is obtained. This design meets the requirement of fitting the ion source system into the restricted space in the high-voltage accelerator's head. [ABSTRACT FROM AUTHOR]

The consecutive transients (CT) method is a plasma diagnostic technique of charge breeder electron cyclotron resonance ion source plasmas. It is based on the short-pulse injection of singly charged ions and the measurement of the resulting transients of the extracted multi-charged ion beams. Here, we study the origin of the large uncertainty bounds yielded by the method to reveal avenues to improve its accuracy. We investigate effects of the assumed electron energy distribution (EED) and the uncertainty inherited from the ionization cross section data of K 4 + – K 12 + ions on the resulting plasma electron density ne, average energy ⟨ E e ⟩ , and the characteristic times of ion confinement τq, electron impact ionization τ inz q , and charge exchange τ cx q provided by the CT method. The role of the EED was probed with Kappa and double-Maxwellian distributions, the latter resulting in a shift of the ne and ⟨ E e ⟩ distributions. The uncertainty of the ionization cross section σ q → q + 1 inz was artificially curtailed to investigate its impact on values and uncertainties of the plasma parameters. It is demonstrated that the hypothetical perfect knowledge of σ q → q + 1 inz significantly reduces the uncertainties of τq, τ inz q , and τ cx q , which motivates the need for improved cross section data. [ABSTRACT FROM AUTHOR]

Due to their significant roles in the radiation belts dynamics, chorus waves are widely investigated in observations, experiments, and simulations. In this paper, numerical studies for the generation of chorus-like waves in a launching device, dipole research experiment (DREX), are carried out by a hybrid code. The DREX plasma is generated by electron cyclotron resonance (ECR), which leads to an intrinsic temperature anisotropy of energetic electrons. Thus the whistler instability can be excited in the device. We then investigate the effects of three parameters, i.e., the cold plasma density nc, the hot plasma density nh, and the parallel thermal velocity of energetic electrons, on the generation of chorus-like waves under the DREX design parameters. It is obtained that a larger temperature anisotropy is needed to excite chorus-like waves with a high nc with other parameters fixed. Then we fix the plasma density and parallel thermal velocity, while varying the hot plasma density. It is found that with the increase of nh, the spectrum of the generated waves changes from no chorus elements, to that with several chorus elements, and then further to broad-band hiss-like waves. Besides, different structures of chorus-like waves, such as rising-tone and/or falling-tone structures, can be generated at different parallel thermal velocities in the DREX parameter range. [ABSTRACT FROM AUTHOR]

Electron cyclotron resonance heating (ECRH) is an important auxiliary heating method which is widely used in magnetic confinement fusion. For the ECRH system on J-TEXT, signals should be transmitted to the control system for monitoring and protection and also to the data acquisition system. Considering the high-voltage and harsh electromagnetic interference environment, reliable fiber-optic transmission links are applied. Transmitted by fiber-optic modules, the response time of digital signals can be less than $1~\mu \text{s}$. According to the ECRH system requirements, two practical analog fiber-optic transmission links based on the voltage-to-frequency and frequency-to-voltage conversion technology have been designed and developed. With IC AD650, the delay time of most analog signals is less than $100~\mu \text{s}$ , and with IC VFC110, critical signal transmission delay can be shortened to $5~\mu \text{s}$. The test results indicate that the designed signal transmission links for ECRH system on J-TEXT are stable and reliable. [ABSTRACT FROM AUTHOR]

Electron cyclotron heating (ECH) of toroidal plasmas has many performance advantages over other plasma heating methods. However, up to the present time, ECH systems have been economically uncompetitive with other RF heating techniques, primarily due to the unavailability of tubes with high unit power in the ECH frequency range. High power RF systems consisting of a large number of small modules become complex and expensive due to the multiplicity of support, ancillary, interlock and control equipment necessary, This need no longer be true with the projected availability of 'megawatt' ECH power tubes. This paper will demonstrate the economic benefits to be obtained from the development of such tubes relative to present ECH and other RF plasma heating systems. [ABSTRACT FROM AUTHOR]

In this paper the layout and preliminary design is described of an installation for the injection of electron-cyclotron wave power into JET. The installation consists of 12 gyrotrons, each 70 GHz, 200 kW RF-output power and a pulse duration of 10 s. A layout for the installation is given using vertical ports at the top and the bottom of the vacuum vessel for launching the RF power into the JET plasma. The electric power for the gyrotrons will be supplied by two high voltage transformer rectifiers with controllable output voltage. Each of the two modulators will use a series tube to regulate the required voltage of 80 kV for six gyrotrons. Possibilities to modulate the RF power are discussed. The entire system will be operated by means of the computerized control and data acquisition system (CODAS). The protection system that ensures a safe and reliable operation of the gyrotrons is described. The microwave considerations for the predesign of the transmission lines and launching systems are covered. [ABSTRACT FROM AUTHOR]

The Quadrumafios electron cyclotron resonance ion source (ECRIS) has been especially designed to permit physical studies of the plasma; this paper describes the source itself (which has been operated at 10 GHz in a first step), its preliminary performances, and the different diagnostics involved, which mainly concern the electron population (ECE, x rays, diamagnetism, microwave interferometer, and electron analyzer). The results are presented and discussed: There is of course a close relationship between the parameters of the plasma and the performances of the source; this point will be discussed in the article. [ABSTRACT FROM AUTHOR]

Microwave-driven ion sources and, in particular, electron cyclotron resonance (ECR) ion sources have customarily been used almost exclusively for the production of multiply charged ions. However, very reliable microwave sources that generate high-current lowemittance beams of singly charged ions have recently been developed for ion implanters and accelerator injectors. In this paper the elementary concepts of high-current microwave ion sources are summarized. The distinction between the ECR and the offresonance coupling of the microwave power into the plasma is addressed as well as the difficulty of extracting high-quality ion beams in the presence of the large magnetic fields associated with microwave ion sources. The features of a selection of high-current microwave ion sources are reviewed. [ABSTRACT FROM AUTHOR]

Hydrogenated silicon carbide (SiC:H) films were deposited using the electron cyclotron resonance (ECR) chemical vapour deposition (CVD) technique from a mixture of methane, silane and hydrogen using diborane as the doping gas. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoconductivity and dark conductivity and activation energy were studied in conjunction with film analysis using the Raman scattering technique. The conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave powers. The ratio (sigmaph/sigmad) of the photoconductivity to the dark conductivity peaked at microwave power of about 600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity. A comparison between the effects of boron doping reprinted in this paper and phosphorus doping reported in our earlier work will be made. [ABSTRACT FROM AUTHOR]

The fixed target experiment NA61 in the North Area of the Super Proton Synchrotron is studying phase transitions in strongly interacting matter. Up to now they used the primary beams available from the CERN accelerator complex (protons and lead ions) or fragmented beams created from the primary lead ion beam. To explore a wider range of energies and densities a request was made to provide primary argon and xenon beams. This paper describes the results of the setting up and 10 week test run of the Ar11+ beam from the 14.5 GHz ECR ion source and the linear accelerator (Linac3) at CERN. [ABSTRACT FROM AUTHOR]

A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eµA of C5+ ion beam should be extracted from the ion source, and the beam emittance better than 75 7r*mm*mrad. In recent commissioning, about 120 eµA of C5+ ion beam was got when work gas was CH4 while about 262 eµA of C5+ ion beam was obtained when work gas was C2H2 gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper. [ABSTRACT FROM AUTHOR]

The clinical operation at the Heidelberg Ion Beam Therapy Center (HIT) started in November 2009; since then more than 1600 patients have been treated. In a 24/7 operation scheme two 14.5 GHz electron cyclotron resonance ion sources are routinely used to produce protons and carbon ions. The modification of the low energy beam transport line and the integration of a third ion source into the therapy facility will be shown. In the last year we implemented a new extraction system at all three sources to enhance the lifetime of extraction parts and reduce preventive and corrective maintenance. The new four-electrode-design provides electron suppression as well as lower beam emittance. Unwanted beam sputtering effects which typically lead to contamination of the insulator ceramics and subsequent high-voltage break-downs are minimized by the beam guidance of the new extraction system. By this measure the service interval can be increased significantly. As a side effect, the beam emittance can be reduced allowing a less challenging working point for the ion sources without reducing the effective beam performance. This paper gives also an outlook to further enhancements at the HIT ion source testbench. [ABSTRACT FROM AUTHOR]

At Peking University (PKU) we have developed several 2.45 GHz Permanent Magnet Electron Cyclotron Resonance ion sources for PKUNIFTY, SFRFQ, Coupled RFQ&SFRFQ, and Dielectric-Wall Accelerator (DWA) projects (respectively, 50 mA of D+, 10 mA of O+, 10 mA of He+, and 50 mA of H+). In order to improve performance of these ion sources, it is necessary to better understand the principal factors that influence the plasma density and the atomic ion fraction. Theoretical analysis about microwave transmission and cut-off inside the discharge chamber were carried out to study the influence of the discharge chamber diameters. As a consequence, experimental studies on plasma density and ion fraction with different discharge chamber sizes have been carried out. Due to the difficulties in measuring plasma density inside the discharge chamber, the output beam current was measured to reflect the plasma density. Experimental results show that the plasma density increases to the maximum and then decreases significantly as the diameter changed from 64 mm to 30 mm, and the atomic ion fraction has the same tendency. The maximum beam intensity was obtained with the diameter of 35 mm, but the maximum atomic ion fraction with a diameter of 40 mm. The experimental results are basically accordant with the theoretical calculation. Details are presented in this paper. [ABSTRACT FROM AUTHOR]

A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.0-1.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper. [ABSTRACT FROM AUTHOR]

A new superconducting 18 GHz electron cyclotron resonance ion source is being developed at the National Fusion Research Institute in South Korea. This source will be dedicated for future application of highly charged ions in the area of matter interaction, diagnostic imaging, and probing. In this paper, we describe the status of the source development consisting of a double electrode biased disk, sputtering systems for metal ion production, diagnostic ports for the extraction region, a variable gap extraction-Einzel lens system, and a low energy beam transport system. [ABSTRACT FROM AUTHOR]

Intermittent enhancement of local electron flux has recently been observed in a linear electron cyclotron resonance plasma. The aim of this paper is to measure the 2-D distribution of the electron flux, which appears at random positions in the plasma cross section, using intensified charge-coupled device imaging. A series of images of the emission from the Ne 2p \(_\mathbf {1}\) state is presented; it clearly demonstrates a circular region of enhanced excitation due to increase in the electron temperature. [ABSTRACT FROM PUBLISHER]

• The Nb 3 Sn sextupole testing coil is fabricated with a round wire. • A mirror structure based on a key and bladder technology. • Describes the mechanical analyses performed to estimate the sextupole's preload. • The stress analysis from assembly to excitation is carried out. • Strain gauge measurements have been compared with the simulation results. The new Nb 3 Sn superconducting magnet system for the fourth-generation 45 GHz ECR source is under development at the Institute of Modern Physics (IMP). A mirror structure of the Nb 3 Sn sextupole testing coil based on an aluminum shell-based structure and bladder & key technology is used for studying the coil's mechanical, thermal and quench performance under realistic conditions. This paper describes the mechanical analyses performed to estimate the sextupole's preload. Based on the three-dimensional finite-element mechanical model, the stress analysis for the process of assembly, cooling down, and charging is carried out. The assembly and strain measurement results of sextupole mirror structure are also introduced in this paper. [ABSTRACT FROM AUTHOR]

The plasma parameters in the 2.45 GHz electron cyclotron resonance (ECR) proton ion source have been measured and optimized at low pressures. These parameters are important as they are related to the beam parameters of the ion source. A detailed plasma characterization study has been conducted using hydrogen as a working gas in the operating pressure and power range 10^-4 – 10^-3 mbar, 400–1000 W of the ion source, respectively. The plasma parameters have been measured in the ECR zone of the plasma chamber. An automatic Langmuir probe and data acquisition system has been used to measure these parameters. In the above-mentioned power and pressure range, the plasma density, plasma electron temperature, and plasma potential measured are in the range 4 \times 10^11 – 6.5 \times 10^11 cm ^-3 , 4–11 eV, and 30–40 V, respectively. The variation of plasma parameters with neutral gas pressure is studied for different microwave powers. A 0-D (global) model has been developed to compare the measured plasma parameter data with the calculated ones. The ion species content in the plasma was measured after extraction using a magnetic mass analyzer and a Faraday cup. A plasma-based model has been developed to compare the measured ion species fraction data with the calculated ones by taking the measured ECR plasma parameters as input. [ABSTRACT FROM PUBLISHER]

An output coupler for a W-band high power wideband gyroamplifier has been designed, manufactured, and experimentally measured. It consists of a high performance sin2-parallel corrugated horn integrated with a broadband multilayer window. The major design requirements are that the horn/window combination must have an input return loss lower than −30 dB over a 10-GHz bandwidth, provide a high quality output beam pattern, and operate under ultrahigh-vacuum conditions. The coupler converts a circular waveguide TE11 mode into the free space Laguerre Gaussian LG00 mode over the frequency band of 90–100 GHz with a measured return loss of between −30 and −40 dB and a simulated Gaussian coupling efficiency of over 99% at 94 GHz. [ABSTRACT FROM PUBLISHER]

Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti+ and Ti++ peaks are observed in the mass scan spectra). This corresponds well with high plasma density ne ∼ 1018 m-3, measured during the HiPIMS pulse. [ABSTRACT FROM AUTHOR]

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS. [ABSTRACT FROM AUTHOR]

In this paper, an ongoing effort to provide a simulation and design tool for electron cyclotron resonance ion source extraction and low energy beam transport is described and benchmarked against experimental results. Utilizing the particle-in-cell code WARP, a set of scripts has been developed: A semiempirical method of generating initial conditions, a 2D-3D hybrid method of plasma extraction and a simple beam transport deck. Measured emittances and beam profiles of uranium and helium beams are shown and the influence of the sextupole part of the plasma confinement field is investigated. The results are compared to simulations carried out using the methods described above. The results show that the simulation model (with some additional refinements) represents highly charged, well-confined ions well, but that the model is less applicable for less confined, singly charged ions. [ABSTRACT FROM AUTHOR]

The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations. [ABSTRACT FROM AUTHOR]

The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking University (PKU). The injector system must transfer 50 keV 50 mA of D+ ion beam to the entrance of the 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and a 1.36 m long low energy beam transport (LEBT) line using two solenoids was developed as the deuteron injector. A [lowercase_phi_synonym]5 mm four-quadrant diaphragm was used to simulate the entrance of RFQ electrodes. The beam parameters are measured after this core with an emittance measurement unit (EMU) and a bending magnet for ion fraction analysis at the end of injector. During the commissioning, 77 mA of total deuteron beam was extracted from PMECR and 56 mA of pure D+ beam that passed through the [lowercase_phi_synonym]5 mm four-quadrant diaphragm was obtained at the position of RFQ entrance with the measured normalized rms emittance 0.12-0.16π mm mrad. Ion species analysis results show that the deuteron fraction is as high as 99.5%. All of the parameters satisfy PKUNIFTY's requirements. In this paper, we will describe the deuteron injector design and report the commissioning results as well as the initial operation. [ABSTRACT FROM AUTHOR]

A new compact version of the 'liquid He-free' superconducting ECR ion source, to be used as an injector of highly charged heavy ions for the MC-400 cyclotron, is designed and built at the Flerov Laboratory of Nuclear Reactions in collaboration with the Laboratory of High Energy Physics of JINR. The axial magnetic field of the source is created by the superconducting magnet and the NdFeB hexapole is used for the radial plasma confinement. The microwave frequency of 14 GHz is used for ECR plasma heating. During the first tests, the source shows a good enough performance for the production of medium charge state ions. In this paper, we will present the design parameters and the preliminary results with gaseous ions. [ABSTRACT FROM AUTHOR]

Using improved beam diagnostic tools, the structure of an ion beam extracted from an electron cyclotron resonance ion source (ECRIS) becomes visible. Especially viewing targets to display the beam profile and pepper pot devices for emittance measurements turned out to be very useful. On the contrary, diagnostic tools integrating over one space coordinate like wire harps for profile measurements or slit-slit devices, respectively slit-grid devices to measure the emittance might be applicable for beam transport investigations in a quadrupole channel, but are not very meaningful for investigations regarding the given ECRIS symmetry. Here we try to reproduce the experimentally found structure on the ion beam by simulation. For the simulation, a certain model has to be used to reproduce the experimental results. The model is also described in this paper. [ABSTRACT FROM AUTHOR]

The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed. [ABSTRACT FROM AUTHOR]

Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper. [ABSTRACT FROM AUTHOR]

Abstract In dentistry, it is necessary to increase the bonding strength between various bioinert zirconia ceramics and the luting cement in order to extend the lifetime of the restoration. As a new method, an ion source was used to implant silicon ions close to the surface of the zirconium-dioxide on nanoscale to improve chemical bonding in between the bonding agent and the zirconium-dioxide. This paper summarizes the main results of a unique technique to functionalize biomaterial surfaces with silicon ions produced by Electron Cyclotron Resonance Ion Source (ECRIS). Highlights • Surface modification has an important role in the field of dentistry • ECR ion source was used to implant silicon ions into zirconia to modify its surface • Implantation resulted strong bond strength between the bonding agent and zirconia implant [ABSTRACT FROM AUTHOR]

This paper reports on an investigation of the hybrid pulsed sputtering source based on the combination of electron cyclotron wave resonance (ECWR) inductively coupled plasma and high power impulse magnetron sputtering (HiPIMS) of a Ti target. The plasma source, operated in an Ar atmosphere at a very low pressure of 0.03 Pa, provides plasma where the major fraction of sputtered particles is ionized. It was found that ECWR assistance increases the electron temperature during the HiPIMS pulse. The discharge current and electron density can achieve their stable maximum 10 μs after the onset of the HiPIMS pulse. Further, a high concentration of double charged Ti++ with energies of up to 160 eV was detected. All of these facts were verified experimentally by time-resolved emission spectroscopy, retarding field analyzer measurement, Langmuir probe, and energy-resolved mass spectrometry. [ABSTRACT FROM AUTHOR]

We have started an experimental and theoretical program to better understand the extraction and transport of intense multiply charged ion beams from an electron cyclotron resonance ion source (ECRIS). In this paper we present the first results of this program concerning a simple, monocomponent He+ beam extracted from an ECRIS. We have calculated the ion trajectories starting from the ECRIS plasma electrode up to the image plane of the analyzing magnet taking into account space-charge effects and fringe fields. The initial phase-space distribution of the He+ beam at the extraction aperture has been calculated with a particle-in-cell code. To check the simulations we have measured beam profiles with a viewing screen both before and after the analyzing magnet. In addition also measurements with a pepperpot emittance meter located behind the analyzing magnet have been performed. We find good agreement between these measurements and simulations showing that (i) there is a significant compensation of the space charge and that (ii) our analyzing magnet causes a severe increase in effective beam emittance. [ABSTRACT FROM AUTHOR]

This paper describes the recent development and commissioning of a pepper-pot emittance meter at the Lawrence Berkeley National Laboratory (LBNL). It is based on a potassium bromide (KBr) scintillator screen in combination with a charged coupled device camera. Pepper-pot scanners record the full four-dimensional transverse phase space emittances which are particularly interesting for electron cyclotron resonance ion sources. The strengths and limitations of evaluating emittances using optical pepper-pot scanners are described and systematic errors induced by the optical data acquisition system will be presented. Light yield tests of KBr exposed to different ion species and first emittance measurement data using ion beams extracted from the 6.4 GHz LBNL electron cyclotron resonance ion source are presented and discussed. [ABSTRACT FROM AUTHOR]

A deuteron radio frequency quadrupoles injector h has been developed at Peking University. A permanent magnetic electron cyclotron resonance (ECR) ion source is used in the injector system. A 50 keV 100 mA proton beam has been extracted from the ECR ion source and the measured normalized rms emittance is 0.11–0.14π mm mrad. A deuteron beam has also been extracted at 50 kV with 83 mA total current and its emittance is less than 0.18π mm mrad. The proton beam transmission has been investigated on a low energy beam transport test bench, and up to 93% transmission can be reached. The new injector with two solenoids has been designed and is being constructed. All the development results will be presented in this paper. [ABSTRACT FROM AUTHOR]

The cold-cathode-type Penning ion gauge (PIG) ion source for the internal ion source of KIRAMS-13 cyclotron has been used for generation of negative hydrogen ions. The dc H-beam current of 650 μA from the PIG ion source with the Dee voltage of 40 kV and arc current of 1.0 A is extrapolated from the measured dc extraction beam currents at the low extraction dc voltages. The output optimization of PIG ion source in the cyclotron has been carried out by using various chimneys with different sizes of the expansion gap between the plasma boundary and the chimney wall. This paper presents the results of the dc H-extraction measurement and the expansion gap experiment. [ABSTRACT FROM AUTHOR]

Wall conditioning is essential in tokamak and stellarator research to achieve plasma performance and reproducibility. This paper presents an overview of recent conditioning results, both from experiments in present devices and modelling, in view of devices with superconducting coils, with focus on W7-X, JT-60SA and ITER. In these devices, the coils stay energised throughout an experimental day or week which demands for new conditioning techniques that work in presence of the nominal field, in addition to the proven conditioning methods such as baking, glow discharge conditioning (GDC) and low-Z wall coating through GDC-plasma, which do not work under such condition. The discussed techniques are RF conditioning without plasma current, both in the ion cyclotron and electron cyclotron range of frequencies, and diverted conditioning plasmas with nested magnetic flux surfaces. Similarities and differences between tokamaks and stellarators are highlighted. Finally a conditional tritium recovery strategy for ITER is proposed based on Ion Cyclotron Wall Conditioning and L-mode plasma results from JET, equipped with an ITER-like wall (beryllium main chamber wall and tungsten divertor). [ABSTRACT FROM AUTHOR]

Scientists have always been interested in the study of electron cyclotron waves in plasma in magnetosphere of a planet. Series of papers are published where AC electric field is taken perpendicular to magnetic field in the magnetosphere. Some scientists have claimed to consider DC electric field, but they are found not to have any electric field. We have discussed propagation of electron cyclotron waves when constant electric field is perpendicular to magnetic field in megnetosphere of a planet. Using bi-Maxwellian distribution function, we have found that for the known value of electron cyclotron frequency ω c , the real oscillation frequency ω r depends only on the temperature anisotropy. We have also found that the growth rate γ increases continuously with the increase of the wavevector k. It is interesting to note that the dispersion relation used in series of papers is erroneous, and it has been taken as universal relation. [ABSTRACT FROM AUTHOR]

In this paper, a W‐band mode converter is designed using a circular corrugated horn and its detailed numerical study is presented. The proposed mode converter was fabricated, and the measured results are validated. The device converts fundamental mode (TE11) into a Hybrid mode (HE11) mode in a frequency range of 75 GHz to 105 GHz. The reflection coefficient is less than −15 dB and a peak directivity of 24.5 dB is achieved. The corrugated horn also shows good mode purity. The measured gain of the device was found to be 18.05 dB. The designed mode converter will be useful in Electron Cyclotron Resonance Heating system for fusion plasma experiments. [ABSTRACT FROM AUTHOR]

The process of divertor detachment, whereby heat and particle fluxes to divertor surfaces are strongly diminished, is required to reduce heat loading and erosion in a magnetic fusion reactor to acceptable levels. In this paper, the physics leading to the decrease of the total divertor ion current (It), or ‘roll-over’, is experimentally explored on the TCV tokamak through characterization of the location, magnitude and role of the various divertor ion sinks and sources including a complete analysis of particle and power balance. These first measurements of the profiles of divertor ionisation and hydrogenic radiation along the divertor leg are enabled through novel spectroscopic techniques. Over a range in TCV plasma conditions (plasma current and electron density, with/without impurity-seeding) the It roll-over is ascribed to a drop in the divertor ion source; recombination remains small or negligible farther into the detachment process. The ion source reduction is driven by both a reduction in the power available for ionization, Precl, and concurrent increase in the energy required per ionisation, Eion: this effect of power available on the ionization source is often described as ‘power starvation’ (or ‘power limitation’). The detachment threshold is found experimentally (in agreement with analytic model predictions) to be ~Precl/ItEion ~ 2, corresponding to a target electron temperature, Tt ~ Eion/γ where γ is the sheath transmission coefficient. The target pressure reduction, required to reduce the target ion current, is driven both by volumetric momentum loss as well as upstream pressure loss. The measured evolution through detachment of the divertor profile of various ion sources/sinks as well as power losses are quantitatively reproduced through full 2D SOLPS modelling through the detachment process as the upstream density is varied. [ABSTRACT FROM AUTHOR]

During the EVEDA (engineering validation and engineering design activities) phase of the International Fusion Materials Irradiation Facility (IFMIF) project, a 125 mA/9 MeV linear prototype accelerator (LIPAc) has to be built, tested and operated in Rokkasho-mura (Japan). Involved in this project for several years, CEA-Saclay designed the injector of this accelerator which is composed of an electron cyclotron resonance ion source, delivering a 140 mA deuteron beam at 100 keV, and a low energy beam transport (LEBT) line to match the beam for the injection into the radio-frequency quadrupole. In this paper, the components of the LIPAc injector are described. The commissioning of the ion source and LEBT with beam started in November 2014. The different phases of the commissioning are explained and some noticeable experimental results obtained with a beam at 100 keV are presented. [ABSTRACT FROM AUTHOR]