Femtosecond laser based x-ray sources and their applications in phase contrast imaging

  • Author / Creator
    Ali, Atif
  • The focus of this dissertation is to study the keV X-ray emission from different Z material to develop compact, quasi-continuous tabletop Kα sources for the application of in-line phase contrast imaging, X-ray diffraction experiments and X-ray microscopy. The emission occurs from plasma produced by focusing 120 fs, 800 nm and 300 μJ Ti:Sapphire laser pulses up to an intensity of few times 1016 W/cm2 on Cu, Fe and Ag metal targets. The main interest of these experiments is to characterize the fast electrons and X-ray emission from the laser plasma interaction. The investigation of X-ray emission energy and spectral characteristics is carried out by employing three detector systems which include filtered pin-diode, Charge Coupled Device and CdTe pulse height detectors. Scaling of photon flux as a function of incident laser energy is measured and related to the dynamics and absorption mechanisms involved in laser matter interaction. Specifically the construction and evaluation of Kα X-ray sources operated at 1 kHz repetition rate is reported with a photon flux of ~ 7×109 photon/s, 3×109 photon/s and 1.4×107 photon/s around the Kα line for Cu, Fe and Ag respectively. These Kα fluences correspond to energy conversion efficiencies of around ηCu = 3×10-5, ηFe = 1.06×10-5 and ηAg = 2×10-7. The Cu and Fe Kα X-ray sources are applied to thin biological specimens and low atomic number (Z) materials to record in-line phase contrast images. It is demonstrated that the laser based Kα sources can serve as alternative sources for conventional X-ray radiography of biological samples in clinical applications.

  • Subjects / Keywords
  • Graduation date
    Spring 2010
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.