acta physica slovaca

Abstract: The magnetic structure of new 10 GHz ECR ion source NANOGUN-10B is described. Small permanent magnets are used for construction of suitable hexapole and axial magnetic field structure. Permanent magnets are made from FeNdB with a remanence of 1.1 T and a coercivity of 800 kA/m. The hexapole consists of 24 trapezoidal segments. The axial magnetic structure is designed of 7 slices of FeNdB permanent magnets defining a magnetic field of 0.58 T in the extraction and 0.77 T near the injection of the UHF area. The magnetic structure internal diameter is 36 mm and the external diameter is 200 mm. The total weight of the magnetic structure is about 36 kg.

Abstract: Preparation of titanium thin film microstructures with dimension of strips down to 5 micrometers, and nanostructures with dimension down to 40 nanometers is discussed. The microstructures were prepared by optical lithography with subsequent Ar+ ion beam etching. Nanostructures were prepared on microstrips by AFM (Atomic Force Microscope) local oxidation of Ti thin film and etched in acid solution. Typical nanostructures - nanodots and nanostrips are presented.

Abstract: The contribution deals with electronic properties of thin oxide/amorphous hydrogenated silicon (a-Si:H) measured by capacitance-voltage (C-V) and charge version of deep level transient spectroscopy (Q-DLTS). The interest was focused on the studies of the interface properties of very thin dielectrics formed by dielectric barrier discharge (DBD) or natively on the a-Si:H layer. These properties were compared with those of oxide layers prepared by chemical oxidation in HNO3. The DBD was used for the preparation of a very thin SiO2 layer on a-Si:H for the first time to our knowledge. Preliminary electrical measurements confirmed that a very low interface states density was detected in the case of the native oxide/a-Si:H and DBD oxide/a-Si:H.

Abstract: A calculation of non-commutative Green function for the two components relativistic equation is presented using the analogous Klein-Gordon one. The result is the sum of two contributions: one is regular and having semi relativistic expression and the second is irregular playing the role of source. An illustration of calculation is given in the case of linear potential.

Abstract: A spectral-domain white-light interferometric technique of measuring the effective thickness of optical elements of known dispersion is presented when a Michelson interferometer with a cube beam splitter is not dispersion balanced and when the spectral interference fringes are resolved over a wide wavelength range. The technique uses processing one of the recorded spectral interferograms by an adequate method to retrieve the unwrapped phase function, the ambiguity of which is removed by a simple procedure based on linear dependence of the optical path difference between interferometer beams on the refractive index of optical elements. The effective thickness of optical elements is given by the slope of the linear dependence. The technique is used to measure the effective thickness of a cube beam splitter alone or combined with a thin plate made of BK7 glass.

Abstract: Production of multi-hydrogen (mH) isotopes in the spallation of 200A GeV sulphur projectile using nuclear emulsion is reported. Yield of mH isotopes is studied and compared with that of the lowest energy (3.7A GeV) data. The two-source emission picture is used to describe the transverse momentum (P_T) distribution of mH isotopes (with and without the effect of 32S ($\gamma$ ,p) 31P channel). The Rayleigh type P_T-distribution seems to be in agreement with the corresponding experimental data. The contributions of low and high temperature emission sources show a dependence on the photonuclear processes.

Abstract: The influence of diamond on carbon nanostructure formation in the arc discharge was investigated. The use of the electrodes made of graphite mixed with diamond micro-crystals and small admixture of catalysts (Ni, Co and Y) enhances the production of single-walled carbon nanotubes. The nanotubes form a web-like product. The presence of diamond drastically decreases the anode erosion rate, and thereby the C_2 radical content in the arc plasma zone, while the average plasma temperature remains unchanged.

Abstract: In the process of intercalation, C_60 samples in the form of polycrystalline films prepared on various substrates are used. To obtain a homogeneous doping we test two geometrical set-ups of our apparatus, horizontal and vertical. In the present work we focus on the study of transport properties of the samples. We demonstrate the temperature dependence of the conductivity of doped C_60 films during the doping process. The time evolutions of the sample resistivity after its exposure to the atmosphere are studied. The structural properties of the samples are examined by X-ray diffraction technique in Bragg-Brentano geometry and Raman Spectroscopy. Scanning Electron Microscopy is used to compare the surface morphology of the undoped and doped C_60 films.

Abstract: New technology for carbon film deposition is presented. The carbon film is condensing from carbon plasma generated by a thermionic vacuum arc with carbon anode. Carbon film is bombarded during deposition by energetic carbon ions at fixed energy. High purity, hydrogen free and nanostructured layers are obtained the characteristic size of structures being in the order of few nanometers.