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Spectroscopic techniques, including photoelectron spectroscopy, diffuse reflectance, and x-ray absorption, are used to investigate the electronic structure and the local structure of LaOBiS 2 − x Se x thermoelectric material. It is found that Se substitution effectively suppresses local distortion that can be responsible for the increased carrier mobility together with a change in the electronic structure. The results suggest a possible way to control thermoelectric properties by tuning of the local crystal structure of these materials. [ABSTRACT FROM AUTHOR]

Presents a study which performed the epitaxial growth and examined the dielectric properties of BaTiO[sub3] films on plutonium electrodes by reactive evaporation. Experimental details; Results and discussion; Conclusion.

The direct measurements of high-frequency electric fields in a plasma bring about significant advances in the physics and engineering of various waves. We have developed an electro-optic sensor system based on the Pockels effect. Since the signal is transmitted through an optical fiber, the system has high tolerance for electromagnetic noises. To demonstrate its applicability to plasma experiments, we report the first result of measurement of the ion-cyclotron wave excited in the RT-1 magnetosphere device. This study compares the results of experimental field measurements with simulation results of electric fields in plasmas. [ABSTRACT FROM AUTHOR]

The self-organization of magnetospheric plasma is brought about by inward diffusion of magnetized particles. Not only creating a density gradient toward the center of a dipole magnetic field, the inward diffusion also accelerates particles and provides a planetary radiation belt with high energy particles. Here, we report the first experimental observation of a "laboratory radiation belt" created in the ring trap 1 device. By spectroscopic measurement, we found an appreciable anisotropy in the ion temperature, proving the betatron acceleration mechanism which heats particles in the perpendicular direction with respect to the magnetic field when particles move inward. The energy balance model, including the heating mechanism, explains the observed ion temperature profile. [ABSTRACT FROM AUTHOR]

The electron density profile of a plasma in a magnetospheric dipole field configuration was measured with a multi-chord interferometry including a relativistic correction. In order to improve the accuracy of density reconstruction, a 75 GHz interferometer was installed at a vertical chord of the Ring Trap 1 (RT-1) device in addition to previously installed ones at tangential and another vertical chords. The density profile was calculated by using the data of three-chord interferometry including relativistic effects for a plasma consisting of hot and cold electrons generated by electron cyclotron resonance heating (ECH). The results clearly showed the effects of density peaking and magnetic mirror trapping in a strongly inhomogeneous dipole magnetic field. [ABSTRACT FROM AUTHOR]

A new high-β and high-density state is reported for a plasma confined in a laboratory magnetosphere. In order to expand the parameter regime or an electron cyclotron resonance heating experiment, the 8.2 GHz microwave power or the Ring Trap 1 device has been upgraded with the installation or a new waveguide system. The rated input power launched rrom a klystron was increased rrom 25 to 50 kW, which enabled the more stable rormation or a hot-electron high-b plasma. The diamagnetic signal (the averaged value or rour magnetic loops signals) or a plasma reached 5.2 mWb. According to a two-dimensional Grad-Shafranov analysis, the corresponding local β value is close to 100%. [ABSTRACT FROM AUTHOR]

The Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet, has created high-β (local β ∼ 70%) plasma by using electron cyclotron resonance heating (ECH). When a large population of energetic electrons is generated at low neutral gas pressure operation, high frequency magnetic fluctuations are observed. When the fluctuations are strongly excited, rapid loss of plasma was simultaneously observed especially in a quiet decay phase after the ECH microwave power is turned off. Although the plasma is confined in a strongly inhomogeneous dipole field configuration, the frequency spectra of the fluctuations have sharp frequency peaks, implying spatially localized sources of the fluctuations. The fluctuations are stabilized by decreasing the hot electron component below approximately 40%, realizing stable high-β confinement. [ABSTRACT FROM AUTHOR]

Formation of high-β electron cyclotron resonance heating plasma and stable confinement of pure electron plasma have been realized in the Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet. The effects of coil levitation resulted in drastic improvements of the confinement properties, and the maximum local β value has exceeded 70%. Hot electrons are major component of electron populations, and its particle confinement time is 0.5 s. Plasma has a peaked density profile in strong field region [H. Saitoh et al., 23rd IAEA Fusion Energy Conference EXC/9-4Rb (2010)]. In pure electron plasma experiment, inward particle diffusion is realized, and electrons are stably trapped for more than 300 s. When the plasma is in turbulent state during beam injection, plasma flow has a shear, which activates the diocotron (Kelvin-Helmholtz) instability. The canonical angular momentum of the particle is not conserved in this phase, realizing the radial diffusion of charged particles across closed magnetic surfaces. [Z. Yoshida et al., Phys Rev. Lett. 104, 235004 (2010); H. Saitoh et al., Phys. Plasmas 17, 112111 (2010).]. [ABSTRACT FROM AUTHOR]

A recent experiment on the Ring Trap 1 device has demonstrated long-term (exceeding 300 s) confinement of non-neutral (pure electron) plasma in a dipole magnetic field; particles diffuse inward, steepening the density gradient and self-organizing into a stable vortex structure [Z. Yoshida et al., Phys. Rev. Lett. 104, 235004 (2010)]. In this study, the internal structures of the plasma are experimentally investigated, and it is shown that the observations are consistent with rigidly rotating charged particle clump. The radial profiles of electrostatic potential and electron density consistently show that the drift velocity has homogeneous angular frequency in the confinement region. The electrostatic fluctuations also rotate rigidly with a phase velocity that agrees with the drift velocity. The magnetospheric system should have a wide application in confining single-species and even multiple-species charged particles. [ABSTRACT FROM AUTHOR]

Diversity of plasma structures, which degenerates in the ideal magnetohydrodynamic model, can emerge in many ways in a two-fluid plasma endowed with a hierarchy of scales. We study the equilibrium structure of high-beta (high temperature and low-density) electrons in a relatively weak magnetic field. Spontaneous flow generation and strong diamagnetism are clear manifestations of the nonideal two-fluid dynamics scaled, respectively, by the ion and electron-inertia lengths (skin depths). The theory predicts stronger flow and diamagnetism in the nonlinear regime of the two-fluid dynamics. [ABSTRACT FROM AUTHOR]

The next generation heavy ion accelerator facility, such as the RIKEN radio isotope (RI) beam factory, requires an intense beam of high charged heavy ions. In the past decade, performance of the electron cyclotron resonance (ECR) ion sources has been dramatically improved with increasing the magnetic field and rf frequency to enhance the density and confinement time of plasma. Furthermore, the effects of the key parameters (magnetic field configuration, gas pressure, etc.) on the ECR plasma have been revealed. Such basic studies give us how to optimize the ion source structure. Based on these studies and modern superconducting (SC) technology, we successfully constructed the new 28 GHz SC-ECRIS, which has a flexible magnetic field configuration to enlarge the ECR zone and to optimize the field gradient at ECR point. Using it, we investigated the effect of ECR zone size, magnetic field configuration, and biased disk on the beam intensity of the highly charged heavy ions with 18 GHz microwaves. In this article, we present the structure of the ion source and first experimental results with 18 GHz microwave in detail. [ABSTRACT FROM AUTHOR]

For RIKEN radio isotope beam project, we started to construct the new superconducting electron cyclotron resonance ion source (SC-ECRIS), which has an operational frequency of 28 GHz, in 2007. The main feature of this ion source is that we can produce large size of resonance zone with six sets of solenoid coils. Before starting, we intensively studied the effect of several key parameters of ECRIS (magnetic field configuration, microwave power density, negatively biased disk) on the plasma. In this article, we describe the effect of key parameters on the plasma and detailed structure of the new SC-ECRIS. [ABSTRACT FROM AUTHOR]

We measured the main plasma parameters (density of electron, temperature of electrons, and ion confinement time) as a function of Bmin and Binj with laser ablation technique. We observed that the Bmin mainly affects the temperature and density of electrons and all of the three parameters increase with increasing the Binj. We also observed that the gas pressure of the plasma chamber at the rf injection side became minimum at the optimum value for Bmin at fixed gas flow. This result indicates that the ionization efficiency becomes maximum at optimum value for Bmin. From these results, it is concluded that the plasma production is strongly dependent on the Bmin (plasma generator). We also observed that the Binj affects the ion confinement time, temperature, and density of electrons. All of the three parameters increase with increasing Binj. [ABSTRACT FROM AUTHOR]

A linac consisting of six rf cavities has been constructed as an energy booster of the RIKEN heavy-ion linac. Various heavy ion beams have been accelerated to 5.8 MeV/u with intensities of more than 1 pμA (particle microampere) in the continuous-wave mode. The booster cavities are based on a quarter-wavelength resonator of a coaxial structure. The first two cavities are frequency-variable in a range from 36 to 76.4 MHz, whereas the last four are operated at a fixed frequency of 75.5 MHz. The design study started in 1997 and the booster was commissioned in 2001. The total voltage gain of the booster ever achieved is 11 MV, which is 70% of the designed value of 16 MV. The high-intensity beams from the booster have been successfully applied to a systematic study on the synthesis of superheavy elements. The beam energy from the ring cyclotron has also been increased, owing to the additional velocity gain provided by the booster. [ABSTRACT FROM AUTHOR]

We have constructed four high performance electron cyclotron resonance (ECR) ion sources in RIKEN and produced a variety of intense beams of heavy ions (e.g., 2 emA of Ar8+, 0.6 emA of Kr13+, 0.3 emA of Xe20+). During the improvement of their performance, we found that several key parameters play essential role on increasing the beam intensity. The parameters are plasma electrode position, magnetic field configuration, property of the chamber wall material and position of a biased disk. To investigate how the parameters influence on the beam intensity, we made a systematic study using the laser ablation method. In these experiments, we observed that Bmin influences the electron density and confinement time of ECR plasma. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Describes the performance of Japanese electron cyclotron resonance ion sources (ECRIS). Production of highly charged ions from Japanese ECRIS; Aluminum coating; Biased electrode; Metallic ion by volatile compounds method.

Explores several time-dependent phenomena in an electron cyclotron resonance ion source. Interchange instability; Ion production; Electron heating processes; Pulsation of the ion-trapping potential well.

Describes a trim coil system design of a superconducting ring cyclotron. Components; Correction for isochroninization of the magnetic field; Numerical procedure developed to generate isochronous fields; Correction schemes for presumed error fields.

For the RIKEN radio isotope factory (RIBF) project, we produced the multicharged uranium beam with two methods. To produce lower charge state U ion beams (14+–20+) we used the UF6 gas as an ionized gas. The typical beam intensity of U14+–20+ was 2–1 particle μA at the extraction voltage of 14 kV. To produce higher charge state U ion beam (U35+), we chose the sputtering method. The beam intensity was 70 particle nA at the extraction voltage of 5.4 kV. Using this method, we successfully produced multicharged U beam continuously for one month without break for RIBF commissioning. [ABSTRACT FROM AUTHOR]

Beam intensities of highly charged Ar ions (Ar11+,12+) were measured as a function of plasma electrode position. We observed that the beam intensity of Ar11+,12+ increased when putting the electrode far from the electron-cyclotron-resonance zone. On the other hand, lower charged heavy ions (Ar8+,7+) dramatically decreased. We observed that the intense beam extraction strongly affects the plasma condition. It may be due to the ion pumping effect. [ABSTRACT FROM AUTHOR]

We have developed a new analytical system that consists of an electron cyclotron resonance ion source (RIKEN 18 GHz ECRIS) and a RIKEN heavy ion linear accelerator (RILAC). This system is called trace element analysis using electron cyclotron resonance ion source and RILAC (ECRIS-RILAC-TEA). ECRIS-RILAC-TEA has several advantages as described in the work of Kidera et al. [AIP Conf. Proc. 749, 85 (2005)]. However, many experimental results during the last several years revealed a few problems: (1) large background contamination in the ECRIS, particularly at the surface of the plasma chamber wall, (2) high counting of the ionization chamber and the data taking system that is monitored by the direct beam from the accelerator, and (3) difficulty in the selection of the pilot sample and pilot beam production from the ECRIS for the purpose of normalization. In order to overcome these problems, we conducted several test experiments over the past year. In this article, we report the experimental results in detail and future plans for improving this system. [ABSTRACT FROM AUTHOR]

In order to investigate the ion-optical parameters of the RIKEN 18 GHz electron cyclotron resonance ion source injection line into the RIKEN RFQ linac, we measured the beam emittance for a wide mass range of the ions. First results indicate a strong extraction current dependence of the normalized emittance. When using the insertion method to produce metallic ions from solid rod with high melting point, we observed that the beam emittance of metallic ions was very large compared to the beam emittance of ions from gaseous element. It may be due to the plasma instability caused by inserting the rod into the plasma deeply. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

As required by the research group of super heavy elements, highly intense beams of 58Fe and 64Ni ions were produced from RIKEN 18 GHz electron cyclotron resonance ion source [Nakagawa et al., Nucl. Instrum. Methods Phys. Res. A 396, 9 (1997)] using the MIVOC method. Maximum intensities of the supplied ion beams were 20 eμA at the extraction voltage of 15.9 kV for 58Fe13+ and 90 eμA at the extraction voltage of 17.5 kV for 64Ni13+. Consumption rate was about 1.2 mg/h for 58Fe and 64Ni, respectively. For the Radio Isotope Beam Factory [Yano, Proceedings of the 15th International Conference on Cyclotron and Their Application [(IOP, Bristol, 1999)] and various requests from users groups, we constructed a double beam injector system for the two ion sources as an external ion source of the Riken Heavy Ion Linear Accelerator [Odera et al., Nucl. Instrum. Methods Phys. Res. A 221, 187 (1984)]. Two ion sources; RAMSES [Arai et al., Nucl. Instrum. Methods Phys. Res. A 491, 9 (2002)] and 18 GHz ECRIS, will be placed at these at the beginning of next year. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Intense beams of heavy ions with medium charge states (1.3 mA of Ar[sup 8+], 200 µA of Xe[sup 20+]) have been produced from a RIKEN 18 GHz electron cyclotron resonance ion source (ECRIS) using various kinds of techniques, e.g., utilization of an aluminum cylinder and a biased disk, and optimization of the plasma electrode position. Furthermore, we have recently constructed two superconducting ECRISs (operational frequencies of 14 and 18 Hz) which have unique characteristics, i.e., they do not need liquid He to obtain the superconductivity of solenoid coils and utilize the G-M refrigerator instead. These sources are suitable to generate intense beams of heavy ions with very high charge states. We obtained 10 µA of Xe[sup 30+], 5 µA of Xe[sup 33+], and 1.5 µA of Xe[sup 36+] at a radio frequency power of 700 W (14 GHz microwave) without using the gas mixing method. Through various experiments, we confirmed that not only the magnetic field strength and microwave power but also the characteristics of the plasma chamber surface play the essential role for the production of highly charged heavy ions. [ABSTRACT FROM AUTHOR]

The effect of the surface of A1[sub 2]O[sub 3] on the beam intensity of highly charged Ar ions is described. To investigate this effect clearly, we directly plated the surface with 20 µm A1[sub 2]O[sub 3] of the Al cylinder (A1[sub 2]O[sub 3] plating method). This cylinder was inserted into the plasma chamber and it covered its inner wall of. We then measured the beam intensity of highly charged Ar ions carefully. By comparing the beam intensity using the A1[sub 2]O[sub 3] plating method and the Al cylinder, it is confirmed that the A1[sub 2]O[sub 3] surface is very effective in increasing the beam intensity of highly charged heavy ions. The best result of 290 eµA of Ar[sup 11+] was obtained by using this method. [ABSTRACT FROM AUTHOR]

To investigate the effect of the plasma electrode position on the beam intensity, we measured the beam intensity of Ar ions, with various charge states as a function of the electrode position. In this experiment, we observed that the beam intensity of highly charged Ar ions is strongly dependent on the electrode position and that there is the suitable position to maximize the beam intensity. The optimum position varies with the charge state of ions. The beam intensity of 1.3 mA for Ar[sup 8+] was obtained at the optimum plasma electrode position. [ABSTRACT FROM AUTHOR]

Focuses on creation of highly charged ions in electron cyclotron resonance ion sources. Electrode preparation after simulations; Biased or electron donor mode; Floating or potential tuner mode.

The residual photocurrent decay following the steady photoexcitation was measured in hydrogenated amorphous silicon as a function of temperature. The data were analyzed by the Fermi level analysis first outlined by Rose [RCA Rev. 12, 362 (1951)]. By introducing a time-dependent recombination rate (∼t-(1-α)), we obtained a good agreement between density of states values obtained from the photoconductivity decay and from space-charge-limited current measurements. [ABSTRACT FROM AUTHOR]

Presents corrections for the study 'Epitaxial Growth and Dielectric Properties of BaTiO[sub3] Films on Pt Electrodes by Reactive Evaporation,' by Y. Kano, K. Ijima, T. Terashima, Y. Bando, Y. Watanabe, H. Kasatani and H. Terauchi.

We observe the generation of a magnetic moment in a dipole plasma as a levitating magnet-plasma system moves in response to electron cyclotron heating and increasing β (magnetically confined thermal energy). We formulate a thermodynamic model that interprets heating as injection of microscopic magnetic moments; the corresponding chemical potential is the ambient magnetic field. [ABSTRACT FROM AUTHOR]