Browsing by Subject "Luminescence spectroscopy"
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Item A spatially resolved spectrometer(Texas Tech University, 1982-05) Herod, David WarrenPhysical evidence examination has only recently began to utilize sophisticated techniques and current technology. The detection of latent fingerprints and characterization of single fibers by laser illumination are areas of current investigation. In this thesis, an instrument that utilizes a laser for sample excitation and control circuitry for spatial resolution is described. Luminescence imaging of latent fingerprints and single fibers, as well as spatially resolved luminescence spectra, are presented. The instrument is tested for both spatial and spectral accuracy as well as spatial reproducibility. The future use of this instrument, in modified form, in computer interface applications is discussed. Although only applications to forensic analysis are explicitly treated, the described instrument is useful for surface analysis generally whenever fluorescence or Raman data are pertinent.Item Nonlinear time axis for multiexponential fitting of luminescence decay times over several orders of magnitude(Texas Tech University, 1990-08) Kher, Alok R.Not availableItem Time-resolved fluorescence studies of dye-polymers as excited by laser and beta-radiation(Texas Tech University, 1997-12) Liu, Lin-IThe fluorescence properties and energy transfer processes of dye-polymers have been investigated with time-resolved fluorescence spectroscopy. Based on an understanding of these characteristics, the new dye-polymers were optimized for potential applications in scintillators and wavelength shifters used in high energy particle detection. The two primary criteria for suitable samples were high quantum efficiencies and short fluorescence decay times. In this work, epoxypolymers were doped with dyes or dye-mixtures. Fluorescence decay times, relative quantum efficiencies, and critical energy transfer radii from Forster kinetics were obtained. A new time autocorrelated two photon counting technique (TATPC) with beta-particle excitation was developed for this work to measure the fluorescence decays from scintillators. Other techniques used were a multi-photon fast analog technique and a single photon counting.