Sökning: "helium"

Visar resultat 1 - 5 av 101 avhandlingar innehållade ordet helium.

  1. 1. Helium Filled Bubbles in Solids Nucleation, Growth and Swelling

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Odd Runevall; KTH.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Helium; Radiation Damage; DFT; molybdenum; MgO;

    Sammanfattning : When nuclear fuel, fabricated for the purpose of transmuting spent fuel is irradiated, significant amounts of He is produced from alpha particles mainly emitted when 242Cm decays into 238Pu. From irradiation experiments it is known that the presence of He in the solids alters the swelling behaviour of the material. LÄS MER

  2. 2. Double Excitations in Helium Atoms and Lithium Compounds

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Marcus Agåker; Uppsala universitet.; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; Soft X-ray emission; resonant inelastic X-ray scattering; double excitations; lithium halide; helium; Atom- och molekylfysik;

    Sammanfattning : This thesis addresses the investigation of doubly excited 2l´nl states in helium atoms and double core excitations in solid lithium compounds.Measurements on He are made in field free environments and under the influence of electric and magnetic fields, using synchrotron based inelastic photon scattering. LÄS MER

  3. 3. Helium measuring system for on-line fuel and control rod integrity surveillance in BWRs

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Irina Larsson; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; helium measurements; helium release; fuel and control rod failures;

    Sammanfattning : Accurate supervision of fuel and control rod integrity in a nuclear reactor core is very important for maintaining a safe and reliable operation of the reactor. Fuel rod failures can cause increased doses to personnel in the power plant, increased backend costs, limitations of the reactor operation and unplanned shut downs, which can lead to large economic losses. LÄS MER

  4. 4. Soft X-ray Scattering Dynamics Close to Core Ionization Thresholds in Atoms and Molecules

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Johan Söderström; Uppsala universitet.; [2007]
    Nyckelord :Physics; Soft X-ray emission; Resonant inelastic X-ray scattering; Double excitations; Helium; X-ray-emission-threshold-electron coincidence; Fysik;

    Sammanfattning : In this Thesis studies of highly excited states in gas-phase atoms and molecules (He, Ne, N2, O2, N2O and CO2) using a variety of synchrotron-radiation based techniques are presented. The three techniques used most frequently are X-ray-emission-threshold-electron coincidence (XETECO), X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy (XPS) and they are all given a brief introduction. LÄS MER

  5. 5. Time-Resolved Studies of Atoms and Ions in the Short-Wavelength Region

    Detta är en avhandling från Atomic Physics, Department of Physics, Lund University

    Författare :Raoul Zerne; [1996]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tellurium; sulphur; gold; magnesium; bismuth; platinum; selenium; helium; Atomic and molecular physics; palladium.; Atom- och molekylärfysik; frequency mixing; VUV spectroscopy; radiative lifetimes; copper; zinc; Fysicumarkivet A:1996:Zerne;

    Sammanfattning : Radiative lifetimes have been studied in neutral copper, gold, magnesium, zinc, tellurium, sulphur, selenium, bismuth and helium and in singly ionised platinum and palladium. The radiative lifetimes were determined by time-resolved spectroscopy following single, two-photon or stepwise laser excitation. LÄS MER