Sökning: "Coherent radiation"
Visar resultat 1 - 5 av 54 avhandlingar innehållade orden Coherent radiation.
1. Ultrafast spin dynamics at the nanoscale : using coherent X-ray and terahertz radiation
Sammanfattning : The field of ultrafast magnetism is driven by the growing need for faster and more efficient magnetic data storage, which comprises the vast majority of the digital information worldwide. However, after more than two decades of intense research, the understanding of the fundamental physical processes governing the transfer of angular momentum necessary for magnetic switching, is still lacking, partially hampered by the appropriate experimental tools. LÄS MER
2. Timing Diagnostics and Coherent Harmonics from a test-FEL
Sammanfattning : The test free-electron laser (test-FEL) at MAX-lab in Lund demonstrated for the first time circularly polarized coherent femtosecond pulses at 66 nm wavelength. A 375 MeV electron bunch was seeded by a femtosecond laser at 263 nm and coherent harmonics were extracted in an APPLE-II type elliptical undulator. LÄS MER
3. Biomarkers of ionising radiation relevant to carcinogenesis : Dose, dose rate and LET dependency of the responses
Sammanfattning : A better understanding of the relationship between ionising radiation (IR) dose, dose rate and radiation quality, and the risk of stochastic effects would improve risk extrapolation from atomic bomb survivors’ data. Owing to insufficient statistical power of epidemiological studies to detect excess incidence of cancer following low doses of IR delivered at low dose rates (LDLDR), as typically encountered in most common human exposure scenarios, radiobiological experiments are fundamental to describe the biological effectiveness of LDLDR and to define the underlying molecular mechanisms. LÄS MER
4. Generation of coherent short-wavelength radiation --- High-order harmonics and x-ray lasers
Sammanfattning : The recent availability of short-pulse, high-intensity, compact lasers has opened doors to new and fascinating areas in atomic physics. Using the Lund Terawatt Laser, the interaction of femtosecond, near-infrared and visible laser radiation with matter at intensities in the range 1013--1017 W/cm2 was studied. LÄS MER
5. Coherent Diffractive Imaging with X-ray Lasers
Sammanfattning : The newly emerging technology of X-ray free-electron lasers (XFELs) has the potential to revolutionise molecular imaging. XFELs generate very intense X-ray pulses and predictions suggest that they may be used for structure determination to atomic resolution even for single molecules. LÄS MER