Search for dissertations about: "radiation physics"

Showing result 21 - 25 of 562 swedish dissertations containing the words radiation physics.

  2. 21. Modelling of laser plasma interaction with applications to particle acceleration and radiation generation

    Author : Benjamin Svedung Wettervik; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plasma; ion acceleration; continuum methods; electron wakefield acceleration; raditation generation; coherent X-ray pulses; Vlasov-Maxwell equations;

    Abstract : The development of laser systems with ultra-high intensities has allowed the study of the relativistic interaction of laser light and ionized matter, plasmas, as well as opened up prospects for compact particle accelerators, generation of high intensity X-ray, XUV radiation, and probing QED-effects, which are present in the high intensity regime. To describe laser matter interaction, it is necessary to self-consistently account for the paths of a large number of particles and the corresponding electromagnetic fields, with the addition of stochastic effects at high laser intensities. READ MORE

  4. 22. Topics on D-branes and Holography

    Author : Mikael Smedbäck; Joseph Minahan; Anton Alekseev; Paolo Di Vecchia; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Theoretical physics; theoretical physics; string theory; D-branes; dualities; AdS CFT; spin chains; Bethe ansatz; boundary conformal field theory; conformal bootstrap; tachyon condensation; string field theory; loop quantum gravity; black holes; area spectrum; Hawking radiation; holographic principle; Teoretisk fysik; Physics; Fysik;

    Abstract : We discuss various aspects of D-branes in string theory and holography in string theory and loop quantum gravity.One way to study D-branes is from a microscopic perspective, using conformal field theory techniques. For example, we investigate the question of how D-branes can be introduced into orbifolded theories. READ MORE

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

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

    Abstract : 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. READ MORE

  6. 24. Modelling and analyzing strong-field effects in quantum plasma

    Author : Haidar Al-Naseri; Gert Brodin; Jens Zamanian; J. Tito Mendonca; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Strong-field physics; Kinetic theory; Quantum plasma; fysik; Physics;

    Abstract : Under the extreme conditions that can be found around dense stars and in the accretion discs of black holes, several strong-field quantum phenomena dominate the dynamics of the plasma. This includes the creation of matter and anti-matter from the vacuum (Schwinger mechanism), radiation reaction and Landau quantization. READ MORE

  7. 25. Ion recombination in liquid ionization chambers : development of an experimental method to quantify general recombination

    Author : Jonas Andersson; Heikki Tölli; Lennart Johansson; Anders Ahnesjö; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; General recombination; initial recombination; liquid ionization chamber; radiation dosimetry; radiofysik; radiation physics;

    Abstract : An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes. READ MORE