Sökning: "x-ray optics"

Visar resultat 16 - 20 av 157 avhandlingar innehållade orden x-ray optics.

  1. 16. Characterisation and application of a laser-based hard x-ray source

    Författare :Matthias Grätz; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray spectroscopy; radiography; medical imaging; differential imaging; time-gated imaging; scatter reduction; Monte Carlo simulation; Atomic and molecular physics; computed tomography; Fysicumarkivet A:1998:Grätz; laser-produced plasma; Atom- och molekylärfysik; X-ray sources;

    Sammanfattning : Hard X-rays are generated by focusing 110 fs laser pulses with intensities of about 1017 W·cm-2 onto solid metal targets. Characteristic properties of this X-ray source are the small source size, the short pulse duration and the high peak flux. LÄS MER

  3. 17. X-Ray Investigations of the Liquid-Liquid Critical Point Hypothesis in Supercooled Water

    Författare :Alexander Späh; Anders Nilsson; Martin Meedom Nielsen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water; supercooled water; x-ray scattering; free electron x-ray laser; liquid-liquid phase transition; liquid-liquid critical point; x-ray speckle visibility spectroscopy; kemisk fysik; Chemical Physics;

    Sammanfattning : This thesis presents experimental x-ray scattering studies on supercooled liquid water. A liquid-liquid transition between two structurally distinct configurations has been found in deeply supercooled water, indicating the existence of a liquid- liquid critical point. LÄS MER

  4. 18. X-ray spectroscopy on diatomic and cationic molecules

    Författare :Ludvig Kjellsson; Jan-Erik Rubensson; Marcus Agåker; Monica Turcato; Michael Meyer; John Bozek; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; resonant inelastic X-ray scattering; cationic molecule; dinitrogen; dioxygen; carbon monoxide; aqueous hydroxyl radical; lifetime-vibrational interference; RIXS; XAS; LVI; N2; O2; CO; H2O; OH;

    Sammanfattning : X-ray spectroscopy have been used to study the electronic structure of diatomic and cationic molecules. X-ray absorption spectra of the molecular cations N2+, O2+, and CO+ have been measured. LÄS MER

  5. 19. Studies of Phonons and Phase Transitions by Time-Resolved X-ray Diffraction

    Författare :Henrik Enquist; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; synchrotron radiation; ultrashort pulses; material science; phase transition; X-ray diffraction; phonon; X-ray detector;

    Sammanfattning : When light is used to study structures, the wavelength limits the size of the details that can be resolved. Visible light can be used to investigate structures as small as a micrometre in size. To study smaller structures a shorter wavelength is required. LÄS MER

  7. 20. Multimode resonant X-ray scattering of free molecules

    Författare :Nina Ignatova; Victor Kimberg; Faris Gel’mukhanov; Sergey Polyutov; Hans Ågren; Piero Decleva; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; core-excited state; nuclear dynamic; wave-packet; resonant inelastic X-ray scattering; Franck-Condon; water; methanol; water isotopomer; pump-probe; quantum chemistry; ultrafast dissociation; Kemi; Chemistry; Fysik; Physics;

    Sammanfattning : This thesis is focused on the role that nuclear dynamics plays in the formation of X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectra of multimode free molecules. A combined approach based on ab initio electronic structure methods and quantum nuclear wave packet dynamics is applied to two systems -- water and methanol in the gas phase. LÄS MER