[en] We suggest to improve the ECR beam optic qualities by taking into account some studies made on other kind of ions sources

[en] In this letter, we describe a unique method of producing hyperthermal neutrals for material processing. The hyperthermal neutrals are produced by accelerating ions across a sheath from a plasma onto a surface. On impact, the ions are neutralized and reflected with ∼50% of their incident energy. These neutrals then bounce off of additional surfaces prior to impacting the target. This unique multiple bounce system was developed for the following reasons: to reduce contamination from sputtered surface material, improve beam uniformity, and reduce UV radiation in the beam path. As a test of this method, we built a prototype beam source and used it to ash photoresist at rates up to 0.022 μm/min. These rates are consistent with a predicted neutral beam flux, 2x10¹⁴cm^-2s^-1. In addition, a simple model is used to indicate that this method is capable of producing economically acceptable ash rates. Comparisons with other neutral-beam production methods are made. copyright 1997 American Institute of Physics

[en] In this source, a plasma is confined in a magnetic configuration constituted by two coil groups. A first group is in the plane defined by the sealed window of an hyperfrequency injector and surrounds it; this group provides the magnetic field which creates and confines the plasma; the second group is feeded in reverse field in respect to the first group and surrounds an ion extraction system. The extraction is made in a magnetic field much lower than the one corresponding to cyclotronic resonance

[en] The authors consider resonance at the harmonics of the electron cyclotron frequency in a magnetic field whose value has an extremum. A calculation is given of the electromagnetic-wave absorption coefficients at electron cyclotron resonance with allowance for different broadening mechanisms for the second and higher harmonics. It is shown that the wave absorption at resonance near the magnetic field extrema is determined by the nature of the absorption line broadening, whereas the absorption coefficient sufficiently far from the extrema is independent of the broadening mechanism and can be defined by a single analytical expression. The possibility of using the results for making local measurements of the plasma density, the electron distribution function and the magnetic field strength in adiabatic traps is discussed. (author)

[en] The propagation and spatial damping of linearly converted electron cyclotron (EC) quasi-longitudinal waves in a magnetized plasma are investigated both analytically and numerically. The dispersion properties of these waves are analysed in the frequency range around the fundamental EC frequency and its second harmonic. Results of the numerical analysis, showing the solution trajectory of the least damped quasi-longitudinal mode in a weakly inhomogeneous plasma, are presented. Large values of the normalized optical depth characterize the damping of the slow backward mode at either the first or the second EC harmonic. The collisional wave damping in low temperature plasmas is also discussed. The results obtained indicate that the strong damping of linearly converted EC quasi-longitudinal waves provides an efficient mechanism for the microwave preionization and plasma heating. (orig.)

[en] The paper presents the experimental examination of a law-hybrid plasma were excited by beatings of two high-frequency electron-cyclotron waves. Resonance nature of excitation of such a wave by the value of magnetic field, dynamics of rise and dependence of wave intensity by plasma density are shown. 14 refs., 5 figs

[en] The injection of high power electrostatic waves into a plasma causes ponderomotive forces to arise. Their action primarily gives rise to a plasma density decrease in front of the launching system and subsequently it affects both the wave injection and propagations. Several experimental and theoretical studies on ponderomotive effects caused by injection of lower hybrid waves (LHW) in linear devices can be found in literature and they reveal a density decrease along the magnetic field whereas no detailed studies on the ponderomotive effects of electrostatic waves in the direction perpendicular to the magnetic field were made up to now. This work concerns an experimental study of the variations of the electron density profiles in a direction perpendicular to the magnetic field occurring in a toroidal plasma when a high power electrostatic wave in the range of the ion cyclotron frequency is launched. As part thereof an analysis of the modifications of the envelope of the electrostatic wave as well as of the coupling properties of the antenna system to the plasma has been performed. By means of this analysis, the presence of density depletions at the edge of the plasma during the application of a high power signal has been revealed. In addition the strong edge electron heating observed in our experiments is presented. The experiment has been carried out on a weakly ionized steady-state hydrogen plasma with major radius R = 40 cm, minor radius r = 8 cm, toroidal magnetic field intensity B_o ∼ 2 kG and vertical magnetic field intensity B perpendicular ∼ 3G. The plasma density is typically 10⁸ cm^-3 at the edge and 10¹⁰ cm^-3 on the axis of the torus

[en] A new mode of operation using only the second stage of the LBL ECR has been developed. This single stage mode produces charge states and currents equal to or better than the traditional two stage operation of the LBL ECR for a variety of gases such as nitrogen, oxygen, and argon. The critical parameter for this mode appears to be conditioning the plasma chamber walls with a coating of SiO₂. Various models to explain this effect will be discussed along with implications for ECR ion source design. A new Advanced ECR ion source which will operate at 14 GHz is being designed for the 88-Inch Cyclotron. Construction is scheduled to begin in the fall of 1988 and test operation should begin in the fall of 1989. The design includes hollow core copper wire solenoids, iron yoke, a Nd-Fe-B sextupole, radial pumping, and access to the plasma chamber. 8 refs., 4 figs., 1 tab

[en] Plasma chamber in an ECR device is an important component. It has vacuum of the order of 10^-7 mbar and it acts as an empty resonant multi-mode cavity for the launched EM microwave. The microwave selectively heats the electrons through ECR on a particular surface in the chamber. Results of investigations on electric field of the EM wave transferring energy to the electrons inside it are given

[en] Experimental results for electron cyclotron resonance in a longitudinally magnetized plasma waveguide (LMG plasma column) are shown as a function of em wave polarization launched into the plasma. The results show the importance of the mentioned polarizations. The plasma electronic density which supply the power transfer effectiveness has a strong dependence with polarization. On the other hand, a slip could be noticed in the RHCP wave (optimum polarization) towards a right hand elliptically polarized wave depending on the work pressure which has a direct relationship with the collisional character of the plasma. (author)