Analysis of a novel X-ray lens for converging beam radiotherapy.

We describe the development and analysis of a new teletherapy modality that, through a novel approach to targeted radiation delivery, has the potential to provide greater conformality than conventional photon-based treatments. The proposed system uses an X-ray lens to reflect photons from a conventional X-ray tube toward a focal spot. The resulting dose distributions have a highly localized peak dose, with lower doses in the converging radiation cone.

Use of Co:MgAlO transparent ceramics in passive Q-switching of an Er:Glass laser at 1.534 µm.

We present the implementation of Co:MgAlO transparent ceramics as passive Q-switching elements in an Er:Glass laser at 1.534 µm. Linearly polarized pulsed output was obtained by Brewster angle inclination of the material Q-switching plate relative to the laser axis.

Radiative and non-radiative transitions of excited Ti cations in sapphire.

We have measured the fluorescence quantum efficiency in Ti:sapphire single crystals between 150 K and 550 K. Using literature-given effective fluorescence lifetime temperature dependence, we show that the zero temperature radiative lifetime is (4.44 ± 0.

Competing radiative and nonradiative decay of embedded ions states in dielectric crystals: theory, and application to Co:AgClBr.

We present a generally applicable theoretical model describing excited-state decay lifetime analysis of metal ions in a host crystal matrix. In contrast to common practice, we include multi-phonon non-radiative transitions competitively to the radiative one. We have applied our theory to Co ions in a mixed AgClBr crystal, and as opposed to a previous analysis, find excellent agreement between theory and experiment over the entire measured temperature range.

Spectroscopy and laser characteristics of copper-vapor-laser pumped pyrromethene-556 and pyrromethene-567 dye solutions.

We measured the basic optical properties of Pyrromethene-567 (P567) and Pyrromethene-556 (P556) dye solutions that are relevant to their application as dye lasers. The fluorescence spectra of methanol solutions show mirror images in relation to the absorption spectra, with Stokes shifts of 29.5 and 37.