Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 114-121). Available also in a digital version from Dissertation Abstracts.

Thesis (PH. D.)--University of Michigan, 1940. / Reprinted from the Physical review, vol. 61, nos. 9 and 10 ... May 1 and 15, 1942. Includes bibliographical references.

Thesis--University of Tennessee. / "ORNL-3328. UC-41--Health and Safety. TID-4500 (17th ed., rev.)." Bibliography: p. 133-138.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2010. / Thesis Advisor(s): Lewellen, John W. ; Harris, John R. "June 2010." Description based on title screen as viewed on July 14, 2010. Author(s) subject terms: Free Electron Laser, Thermionic, Dispenser, Cathode, Outgassing, Cessium evaporation. Includes bibliographical references (p. 119-124). Also available in print.

Made available in DSpace on 2014-10-09T12:24:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:02Z (GMT). No. of bitstreams: 1 00881.pdf: 3058836 bytes, checksum: 1addda2a16ebe5e5213e776388198693 (MD5) / Tese (Doutoramento) / IEA/T / Instituto de Energia Atomica

Cesium adsorption on Pt(111) and its coadsorption with iodine and oxygen is studied in this dissertation. The work function during Cs dosing first decreases and at Δφ≈ 3 eV ( Cs = 0:15) the surface undergoes surface transition between a disordered anomalous state (Pt(111)(anom)-Cs) and islands of a Pt(111)(2 x 2)-Cs causing a change in the slope of the work function curve. The work function curve reaches minimum at -5:5 eV where the surface is fully covered with the Pt(111)(2 2)-Cs structure (θCs = 0:25). Further Cs dosing results in a work function increase and the surface undergoes a phase transition to Pt(111)(p3 p3)-Cs. The Cs saturated structure (Pt(111)(ihcp)-Cs) has an hexagonal symmetry with the unit cell vector aligned with the h1; 0i direction of the substrate. Cs in the anomalous state desorbs from the surface in a high-temperature TDS peak (> 1000 K). When the lock-in TDS detection technique is used, this peak appears to be phase shifted by 180 when compared to the desorption peak of normally adsorbed Cs ( Cs > 0:15) . This phase shift is a consequence of a positive charge of desorbing Cs. The TDS and work function behavior were explained by a Monte Carlo desorption model incorporating di¤erent desorption behavior for all four observed adsorption phases. When O2 is dosed on a Pt(111)-Cs surface, the maximum coverage of oxygen bonded to the surface is significantly increased in comparison to Pt(111). Anomalously adsorbed Cs activates the O2 bond but does not interact strongly with coadsorbed O. However, when O2 is dosed on Pt(111)(ihcp)-Cs, the oxygen first adsorbs to a sub-layer adsorption site and strongly interacts with Cs. The oxygen in this state is responsible for thermal stabilization of coadsorbed Cs. When iodine is coadsorbed on a Pt(111)-Cs surface, it also strongly interacts with and thermally stabilizes Cs. During the desorption of Cs,I layers, some Cs and I desorb together in the form of a CsxIy cluster. The surface structures observed by LEED during the coadsorption of Cs and I are in good agreement with atomic arrangements predicted for ionic layers. The validity of this conclusion and the general behavior of ionic layers was checked by an electrostatic energy calculation for various structures. / Graduate / 0494 / 0748

Made available in DSpace on 2014-10-09T12:24:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:02Z (GMT). No. of bitstreams: 1 00881.pdf: 3058836 bytes, checksum: 1addda2a16ebe5e5213e776388198693 (MD5) / Tese (Doutoramento) / IEA/T / Instituto de Energia Atomica

Criteria are developed for the design of an experiment to study steady radiation fronts in Cs vapor. According to these criteria, a pulsed light source of supposedly sufficient intensity (≃10²²photons/cm²-sec) and pulse length (≃90ys) was built, and an absorption tube for Cs vapor inside an oven was developed (through several models) which produced a maximum absorber density of ≃10¹⁸particles/cm³. Light and electrical probe measurements were carried out to detect ionizing radiation fronts in the cesium. While the light measurements were inconclusive due to stray light problems, the probe measurements showed that photoionization takes place but at a much lower rate than expected. A subsequent study of the light source confirmed that indeed the light source, a constricted capillary arc, driven by a 90μs square current pulse, has a much lower intensity in the test section of the absorption tube than is required to drive a front. The low intensity of this light pulse rendered the initial aim of the experiment namely the study of steady ionization fronts in cesium vapor, unattainable with the available apparatus. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis explores gamma rays from neutron excitation of Cs133.

No description available.