Sökning: "x-rays"

Visar resultat 11 - 15 av 191 avhandlingar innehållade ordet x-rays.

1. 11. Sources of Dust Extinction in Type Ia Supernovae : Measurements and constraints from X-rays to the Infrared

   Författare :Joel Johansson; Edvard Mörtsell; Ariel Goobar; Rahman Amanullah; Bruno Leibundgut; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; interstellar dust; circumstellar dust; cosmology; fysik; Physics;

   Sammanfattning : The use of Type Ia supernovae (SNe Ia) as distance indicators is essential for studying the expansion history of the Universe and for exploring the nature of dark energy. However, a lack of understanding of the progenitor systems and the empirically derived colour-brightness corrections represent severe limitations for SNe Ia as cosmological probes. LÄS MER

3. 12. Element 115

   Författare :Ulrika Forsberg; Kärnfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; superheavy elements; element 115; new elements; alpha decay; X rays; gamma rays; nuclear structure; spontaneous fission; Fysicumarkivet A:2016:Forsberg; kärnstruktur; supertunga grundämnen; nya grundämnen; alfasönderfall; röntgenstrålning; gammastrålning; spontan fission; element 115; spektroskopi;

   Sammanfattning : This thesis is devoted to detailed studies of element 115 decay chains using the highly efficient multi-coincidence alpha, electron, gamma and X-ray detector setup TASISpec at the gas-filled separator TASCA at GSI, Darmstadt, Germany. In a three-week long experiment thirty new decay chains assumed to stem from element 115 isotopes were observed together with the very first detections of gamma rays and potential X-rays from these nuclei. LÄS MER

4. 13. In vitro and in vivo aspects of intrinsic radiosensitivity

   Författare :Karl Brehwens; Andrzej Wojcik; Siamak Haghdoost; Wolfgang Dörr; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radiation biology; changing dose rates; cytogenetics; hypothermia; X-rays; radiotherapy; osteoradionecrosis; biomarkers; oxidative stress; individual radiosensitivity; molekylär biovetenskap; Molecular Biosciences;

   Sammanfattning : This thesis focuses on how physical and biological factors influence the outcome of exposures to γ/X-rays. That the dose rate changes during real life exposure scenarios is well-known, but radiobiological data from exposures performed at increasing or decreasing dose rates is lacking. LÄS MER

5. 14. Factors modifying cellular response to ionizing radiation

   Författare :Lei Cheng; Andrzej Wojcik; Siamak Haghdoost; Lovisa Lundholm; Penelope A. Jeggo; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radiation biology; DNA damage; gene expression; alpha particles; X-rays; mixed beams; gamma rays; hypothermia; dose rate.; molekylär biovetenskap; Molecular Bioscience;

   Sammanfattning : Many physical factors influence the biological effect of exposure to ionizing radiation, including radiation quality, dose rate and temperature. This thesis focuses on how these factors influence the outcome of exposure and the mechanisms behind the cellular response. LÄS MER

7. 15. Zone Plates for Hard X-Ray Free-Electron Lasers

   Författare :Daniel Nilsson; Ulrich Vogt; Thomas Tschentscher; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray optics; Zone plates; XFEL; x-rays; free-electron laser; heat transfer;

   Sammanfattning : Hard x-ray free-electron lasers are novel sources of coherent x-rays with unprecedented brightness and very short pulses. The radiation from these sources enables a wide range of new experiments that were not possible with previous x-ray sources. Many of these experiments require the possibility to focus the intense x-ray beam onto small samples. LÄS MER