No abstract available

No abstract available

[en] The velocity of vacuum arcs in a magnetic field and the erosion at the cathode have been investigated for Al + 3% Mg and stainless steel. The arc currents were adjusted between 16.6 A and 70 A and a magnetic induction of 0.02 to 0.1 T was applied. The arc current and the arc velocity can be measured reproducibly only after conditioning of the cathode surface by 20 to 40 arc operations. For conditioned cathodes at room temperature the arc velocities increase with arc current and magnetic induction. For higher cathode temperatures the arc velocity decreases while the erosion yields and the crater size increases. (orig.)

[en] For industrial CVD of Y₁Ba₂Cu₃O_6+x superconductors single source evaporation systems are preferred. After a comparison of different evaporation systems the deposition process with an ultrasonic nebulizer is described. A solution of thd complexes (thd = 2.2.6.6-tetramethyl-3.5-heptandedionate) in diglyme was nebulized and evaporated in a heated tube. The deposition process was carried out with the following deposition parameters: 0.20 mol/h diglyme with 0.03 mol/l thd-complexes, 1.5 mol/h O₂, 0.13 mol/h Ar. The total pressure was 2,000 - 2,500 Pa and the deposition temperature in the range of 800 - 950C. The deposition process is controlled by gas transport as is indicated by the small temperature dependence of the deposition process and the good agreement of the calculated and measured deposition profiles in a cylindrical hole. Carbon (some wt%) was found in the coatings. The maximum transition temperature was 79 K. In comparison experiments with a direct spray process into the reactor are described

[en] Chemical Vapor Deposition generally provides the possibility of large scale production of thin superconducting films. For this purpose a process must fulfill the following criteria: - good controllability and stability of the process, - possibility of transformation from laboratory scale to industrial scale (up-scaling), - growth on technical substrates (i.e. hastelloy, polycrystalline YSZ). In conventional CVD (one thermal evaporator for each component) occur problems which limit reproducibility, scale-up possibility and controllibility of the process: - thermal instability of Ba-precursors, limitting process duration and evaporation constance, - high sensitivity on fluctuations of evaporation temperatures. To solve these problems two different single source CVD-systems have been developed. In both systems the metalorganic precursors (Y(thd)₃, Ba(thd)₂, Cu(thd)₂) are dissolved in an organic solvent (i.e. diglyme). Thereby the ratio between the components can be adjusted very precisely and cannot change within the process time. The first system is based on an ultrasonic nebulizer as single-source evaporator. It has been connected to either a hot-wall and a cold-wall reactor. Results of our experiments using this setup are presented subsequently. The second, recently developed system utilizes a new band-evaporator, which is connected to a hot-wall reactor. (orig.)

[en] The Compact Linear Collider (CLIC) is an option for a future e"+e"- collider operating at centre-of-mass energies up to 3 TeV, providing sensitivity to a wide range of new physics phenomena and precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages: √(s) = 350 GeV, 1.4 and 3 TeV. The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung (e"+e"- → ZH) and WW-fusion (e"+e"- → Hν_e anti ν_e), resulting in precise measurements of the production cross sections, the Higgs total decay width Γ_H, and model-independent determinations of the Higgs couplings. Operation at √(s) > 1 TeV provides high-statistics samples of Higgs bosons produced through WW-fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes e"+e"- → t anti tH and e"+e"- → HHν_e anti ν_e allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit. (orig.)