Sökning: "helium"

Visar resultat 16 - 20 av 124 avhandlingar innehållade ordet helium.

  1. 16. Knock-out of non-nucleonic components from helium

    Författare :Allan Hallgren; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : .... LÄS MER

  3. 17. High-Resolution Measurement of the 4He(g,n) Reaction in the Giant Resonance Region

    Författare :Björn Nilsson; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tagged photons; photonuclear reactions; liquid helium; neutron detectors; liquid scintillators; giant resonances; angular distributions; differential cross sections; total cross sections; Nuclear physics; Kärnfysik; Fysicumarkivet A:2003:Nilsson;

    Sammanfattning : A comprehensive near-threshold 4He(g,n) absolute cross section measurement has been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 20 < Eg < 45 MeV tagged photons (covering the Giant Dipole Resonance energy region) were directed towards a liquid 4He target, and knocked-out neutrons were detected in a pair of 60 cm x 60 cm vetoed NE213A liquid scintillator arrays. LÄS MER

  4. 18. Ion Beam Analysis of First Wall Materials Exposed to Plasma in Fusion Devices

    Författare :Per Petersson; Göran Possnert; Anders Hallén; Marek Rubel; Eduardo C. Alves; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ion beam analysis; Microbeam; Plasma wall interaction; Deuterium; Beryllium; Carbon fibre composites; Divertor; Nuclear reaction analysis; Helium-3; Plasma physics with fusion; Plasmafysik med fusion; Ion Physics; Jonfysik;

    Sammanfattning : One major step needed for fusion to become a reliable energy source is the development of materials for the extreme conditions (high temperature, radioactivity and erosion) caused by hot plasmas. The main goal of the present study is to use and optimise ion beam methods (lateral resolution and sensitivity) to characterise the distribution of hydrogen isotopes that act as fuel. LÄS MER

  5. 19. Exchange

    Författare :Lars A. Salmi; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; metastable helium; secondary electrons; surface states; overlayers; single-triplet conversion; Auger deexcitation; spin-polarization; exchange; Auger neutralization;

    Sammanfattning : .... LÄS MER

  7. 20. Advanced In-Core Fuel Cycles for the Gas Turbine-Modular Helium Reactor

    Författare :Alberto Talamo; Waclaw Gudowski; Kurt Kugeler; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic physics; Atomfysik;

    Sammanfattning : In 1789 a German chemist, Martin Heinrich Klaproth, announced the discovery of a new element: uranium; few years later, the head of father of the modern chemistry, Antoine Lavoisier, was swept away by guillotine: a new era was destined to be opened, either where energy would have been produced in large scale by nuclear processes delivering hundreds of times the energy of chemical processes or where a mass of people, revolutionary or not, would have been melted down into a couple of seconds. After a quite long time, on the 2nd December 1942, the first nuclear reactor has been put into operation by Enrico Fermi in Chicago; few years later, came also the dark side utilization of fissile materials in Hiroshima and Nagasaki. LÄS MER