We insert two probes in the upstream and the downstream regions with respect to the electron cyclotron resonance (ECR) zone which is formed at the center of mirror fields. We measure simultaneously plasma parameters in those regions by each of them under the same operating condition. We measure ion saturation currents Iis and electron energy distribution functions at two positions. We obtain measurement results that suggest the more efficient ECR on the side closer to the microwave-launchings than those on the other side. It is consistent with the accessibility condition of the right-hand polarization wave. We also compare the charge state distributions of Ar ion beams extracted in the case of launching microwaves from the coaxial semi-dipole antenna and those from the rod antenna. We observe the higher multicharged ion beam currents at the low microwave powers in the case of the rod antenna than those in the case of the coaxial semi-dipole antenna. We also confirm stable increasements of ion beam currents at considerably high microwave powers in the case of the coaxial semi-dipole antenna. Based on the experimental results, we propose a new microwave-launching method, “dual-ECR heating” and report its preferable preliminary experimental results in this paper.

Based on experimentally obtained plasma parameters in an electron cyclotron resonance (ECR) ion source (ECRIS) and theoretical considerations, it is turned out the essential factor that is currently presumed to define the increase in multicharged ion current in ECRIS is not simply the density limit of ordinary wave and right-hand cutoffs, but is also higher density one of left-hand cutoff. There are two response guidelines that can be considered to make it possible to overcome limitations, except for the conventional simply increasing the frequency and the magnetic field strength. One is advanced high-frequency resonance, i.e., upper-hybrid resonance (UHR), which is conversion from electromagnetic to electrostatic wave essentially without cutoff. The others are due to the introduction of lower frequency waves than ECR’s one, which has no density limit in a more essential sense. The latter is the introduction of lower-hybrid resonance (LHR) or ion cyclotron resonance (ICR). We will describe experimentally obtained plasma parameters, and will discuss these candidate applications.

An electron cyclotron resonance (ECR) ion source (ECRIS) can generate an available amount of multicharged ions, thus it is not limited for use in the field of accelerator science, but also in medical/biological fields, such as for heavy ion beam cancer treatment and ion engines. The processes of generating multicharged ions are mainly sequential collisions of a direct ionization process by electrons, and have good ion confinement characteristics. By utilizing this confinement property, we have synthesized iron-encapsulated fullerenes, which are supramolecular and can be expected to have various high functions. Fullerenes and iron ions are vaporized from pure solid materials and introduced into the ECRIS together with the support gas. We investigated conditions under which fullerene ions do not dissociate and iron ions are generated so that both can coexist. Generated ions are extracted from the ECRIS and separated by mass/charge with a dipole magnet, and detected with a Faraday cup. This measurement system is characterized by a wide dynamic range. The charge-state distribution (CSD) of ion currents was measured to investigate the optimum conditions for supramolecular synthesis. As a result, a significant spectrum suggesting the possibility of iron-encapsulated fullerenes was obtained. This paper describes the details of these experimental results.

At present it is necessary the satellite lifetime 10-15 years for operating in space. Xenon is used as fuel for ion engines of satellites. There are problems of accumulated damages at irradiation and sputtering by low energy Xe ion from the engine. It is required to construct database of sputtering yield of ion beams in the low energy region from a hundred eV to 1keV. We are trying to investigate experimentally sputtering yield on satellite component by irradiating the low energy Xe q+ ion beams. We use the electron cyclotron resonance ion source (ECRIS) in the irradiation experiments. We decelerate the beam energy to several hundred eV after extraction at high voltage 10kV. It is found we cannot neglect the contribution of the space potential of the plasma in the ECRIS of several tens eV. We measured the plasma parameters and ion beam deceleration characteristics in operating conditions on ECRIS. As the results, it was found in operating ECRIS condition of low charge state ion being dominant that the space potential of the ECRIS has an effect of 10∼20% at the beam energy at about 100eV in conducting irradiation experiments on satellite component materials.

We have been using an electron cyclotron resonance ion source (ECRIS) for ion beam production, and it is desirable to construct a universal ECRIS that can produce ions with a wide range of mass/charge ratios, e.g. from several to several thousand. We investigated the characteristics of ions with high mass/charge ratios, e.g., iron endohedral fullerenes production, which requires low voltage beam extraction. We investigated the characteristics of the ion beam extraction at low extraction voltage. It is found that the beam current almost obeyed the Child-Langmuir law for various ion species. The space potential of the plasma in the ion source can be obtained from the relation between the extraction voltage and the square of the magnetic field strength of the dipole magnet. It is found that space potential values are larger with large charge state of ions, in low gas pressure condition and in high microwave incident power. At the same time, the plasma space potential was measured by using a Langmuir probe and compared with the ion beam method. It is found that same trend is confirmed with probe method.