[en] This work deals with the influence of the orientation of an applied static magnetic field on the mixed state properties of high temperature superconducting cuprates. The mixed state is characterized by the presence of vortices (quanta of magnetic flux). Their properties have been tested via the dynamic approach of the shielding of an ac magnetic field. In pristine Bi₂Sr₂CaCu₂O₈ crystals the first order transition of the vortex system from an ordered to a disordered state has been studied. It has been found that in the material the transition is mainly determined by the component of the field perpendicular to the superconducting copper oxide layers. However, the value of this component at the transition diminishes with the increase of the field component parallel to the layers. This is explained by the decrease of the Josephson coupling between 2D vortices in neighbouring planes in the presence of a parallel component. In heavy ion irradiated Bi₂Sr₂CaCu₂O₈ the subject under investigation has been the pinning of the vortices by the irradiation tracks. These defects push the irreversibility line towards higher fields. In the field range that has become irreversible after irradiation pinning by columnar defects is anisotropic. This anisotropy in pinning indicates that a coupling exists between the 2D vortices that form a vortex line, in contrast to the behaviour in the pristine material in the same field range. HgBa₂Ca₂Cu₃O₈ with columnar defects shows essentially the same behaviour as Bi₂Sr₂CaCu₂O₈, the differences being well explained by the lower anisotropy of HgBa₂Ca₂Cu₃O₈ which leads to a more linear character of the vortices. Finally, it has been shown that in pristine Bi₂Sr₂CaCu₂O₈ the concentration of the vortices in the center of the sample is explained by the surface barrier alone. (author)

[en] The CUPID-Mo experiment is searching for neutrinoless double beta decay in ${}^{100}$Mo, evaluating the technology of cryogenic scintillating Li${}_2^{100}$MoO${}_4$ detectors for CUPID (CUORE Upgrade with Particle ID). CUPID-Mo detectors feature background suppression using a dual-readout scheme with Li${}_2$MoO${}_4$ crystals complemented by Ge bolometers for light detection. The detection of both heat and scintillation light signals allows the efficient discrimination of $\mathrm{\alpha <!--\; ??\; -->}$ from $\mathrm{\gamma <!--\; ??\; -->}$&$\mathrm{\beta <!--\; ??\; -->}$ events. In this proceedings, we discuss results from the first 2 months of data taking in spring 2019. In addition to an excellent bolometric performance of 6.7 keV (FWHM) at 2615 keV and an $\mathrm{\alpha <!--\; ??\; -->}$ separation of better than 99.9% for all detectors, we report on bulk radiopurity for Th and U. Finally, we interpret the accumulated physics data in terms of a limit of $T_{1/2}^{0\mathrm{\nu <!--\; ??\; -->}}>3\times <!--\; ??\; -->{10}^{23}$ yr for ${}^{100}$Mo and discuss the sensitivity of CUPID-Mo until the expected end of physics data taking in early 2020.

No abstract available

[en] Based on a comprehensive set of transport parameters of electrons in methane derived from single electron spectra in the range of field 0.01-15 Td we determined a set of elastic and inelastic scattering cross sections up to 3 eV. The necessity to include anisotropic elastic scattering in a Boltzmann analysis of methane is demonstrated. In addition the drift velocity in a mixture of methane with helium was used to enhance the reliability of the derived cross sections. The low energy part of the cross sections for elastic scattering is subject to a MERT analysis and is compared with total cross section data from single scattering experiments. (orig.)

[en] This report presents an evaluation of service experience with nuclear and fossil feedwater pumps. The scope includes all US commercial light water reactors over 430 MWe in operation in June 1978 and all US fossil fired units over 600 MWe in operation in December 1977. Presented in the report are: the root causes of repetitive failures of feedwater pumps, an evaluation of past practices, engineering judgments and economic trade-offs which have led to feedwater pump unavailability, specific actions which utilities can implement to improve the availability of new and existing feedwater pumps, and recommendations for further research which should lead to improved feedwater pump reliability

[en] Short note

[en] Short note

[en] A comprehensive experimental study of helium based counting gases is presented. The properties of electron transport and gas amplification in mixtures of helium with a variety of molecular additives have been studied and compared with a standard argon based gas. Mixtures of helium with isobutane or CF₄ combine a low multiple scattering with excellent gas amplification properties and transport parameters. (orig.)

[en] In silicon nanocluster (Si-NC) memories, Si-NC embedded in the gate oxide of an MOSFET are used to store and release electrons thereby modifying the threshold of the transistor. This paper describes the formation of its core functional structure, the Si-NC MOS memory capacitor, by annealing a SiO₂/SiO_x (x<2) stack, deposited onto a thin direct tunneling oxide on silicon by a sputtering method. To achieve a high density of isolated Si-NC, both, the initial silicon excess in the SiO_x layer and the thermal annealing treatment must be optimized. Optimum conditions are expected just at the end of the nucleation stage of the NC ensemble. Therefore, the effect of various rapid thermal anneals (RTA) on SiO_x/Si structures with different silicon excess x was investigated focusing on two optical methods: infrared absorption and photoluminescence (PL). The rate of nucleation and phase separation were found to depend strongly on both, silicon excess and annealing temperature. The characteristic size dependence of Si-NC PL was used to differentiate annealing regimes yielding NC ensembles being 'frozen' in the process of nucleation or in their growth/ripening phase, respectively. Additionally, Si-NC MOS memory capacitors were prepared and characterized using both, optical and electrical tests. The devices prepared under optimized conditions yield a high flat-band shift and good charge retention characteristics

[en] The conceptual design of a nuclear waste repository in basalt is described. Nuclear waste packages are placed in holes drilled into the floor of tunnels at a depth of 3700 ft. About 100 miles of tunnels are required to receive 35,000 packages. Five shafts bring waste packages, ventilation air, excavated rock, personnel, material, and services to and from the subsurface. The most important surface facility is the waste handling building, located over the waste handling shaft, where waste is received and packaged for storage. Two independent ventilation systems are provided to avoid potential contamination of spaces that do not contain nuclear waste. Because of the high temperatures at depth, an elaborate air chilling system is provided. Because the waste packages deliver a considerable amount of heat energy to the rock mass, particular attention is paid to heat transfer and thermal stress studies. 3 references, 31 figures, 3 tables