Sökning: "Cosmic Radiation"

Visar resultat 1 - 5 av 40 avhandlingar innehållade orden Cosmic Radiation.

  1. 1. The microdosimetric variance-covariance method used for beam quality characterization in radiation protection and radiation therapy

    Författare :Jan Erik Lillhök; Lennart Lindborg; Bernd Grosswendt; Stockholms universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; ionizing radiation; radiation quality; radiation protection; radiation therapy; microdosimetry; nanodosimetry; variance-covariance method; Radiological physics; Radiofysik; medicinsk strålningsfysik; Medical Radiation Physics;

    Sammanfattning : Radiation quality is described by the RBE (relative biological effectiveness) that varies with the ionizing ability of the radiation. Microdosimetric quantities describe distributions of energy imparted to small volumes and can be related to RBE. LÄS MER

  2. 2. Antiprotons in the Cosmic Radiation Measured by the CAPRICE98 Experiment

    Författare :David Bergström; KTH; []
    Nyckelord :Antiprotons; Antimatter; Protons; Cosmic Radiation; Magnetic spectrometer; RICH detector;

    Sammanfattning : .... LÄS MER

  3. 3. A New Measurement of Low Energy Antiprotons In the Cosmic Radiation

    Författare :Petter Hofverberg; Mark Pearce; Stephane Coutu; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; cosmic radiation; antiprotons; solar modulation; Astroparticle physics; Astropartikelfysik;

    Sammanfattning : New measurements of the antiproton flux and the antiproton-to-proton flux ratio at the top of the atmosphere between 80 MeV and 2.0 GeV are presented. The measurement was conducted from July 2006 to March 2008 with the PAMELA satellite experiment. LÄS MER

  4. 4. Simulations of Cosmic Reionization : Shapes & Sizes of H II regions around Galaxies and Quasars

    Författare :Martina M. Friedrich; Garrelt Mellema; Jonathan Pritchard; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Sammanfattning : After the era of recombination, roughly 360 000 years after the big bang (redshift 1100), the universe was neutral, continued to expand and eventually the first gravitationally collapsed structures capable of forming stars, formed. Observations show that approximately 1 billion years later (redshift 6), the Universe had become highly ionized. LÄS MER

  5. 5. On the Escape of Lyman Radiation from Local Galaxies

    Författare :Elisabet Leitet; Nils Bergvall; Erik Zackrisson; Bengt Gustafsson; Duilia F. De Mello; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Galaxies; starbursts; spiral galaxies; Lyman continuum; Lyman alpha; leakage; cosmic reionization; escape fraction; Astronomy; Astronomi;

    Sammanfattning : Cosmic reionization was most likely initiated by star forming dwarf galaxies. Little is known about the physical mechanisms allowing ionizing Lyman continuum (LyC) photons to escape from galaxies, but to learn more we can study local galaxies in detail. LÄS MER