Development of a continuously operating source of vacuum ultraviolet and soft X-radiation Final report

Development and design of continuously operating source of vacuum ultraviolet and soft X-ray

Fluorescence of Oil Well Cuttings Under The Action of Ultraviolet Light As Pertaining To Depth of Wells Investigated

In 1937, Lippert (6) published a survey of the radioactive properties of subterranean waters of Ellis County, Kansas. In 1940, Bell, Goodman, and Whitehead (1) reported a survey on the radioactivity of sedimentary rocks and associated petroleum. In 1944, w. L. Russell (10) reported on the total gamma ray activity of sedimentary rocks as indicated by Geiger-Mueller Counter determination. Lastly, in 1949, M. w. Johnston (5) made a survey of radioactivity of oilwell drilling fluid with depth of wells. Since Johnston\u27s work cited above included only producing wells it was thought worthwhile to continue this investigation to include wells both in producing pools and in unproven territory. An additional new approach to this whole matter of geophysical prospecting for oil is to test oilwell cuttings for fluorescence since it is well known that particles from oil-bearing horizons do fluoresce under the action of ultraviolet light. While the fluorescence of oil under the action of ultraviolet light has been known for many years, the method of detecting the presence of oi l by means of the fluorescence of oilwell cuttings is not in general use among geologists at the present time, at least not in this region. Consequently it was decided to select six locations where drilling was contemplated, three in the Sutor Pool in Rooks County ; and, three new locations in unproven territory. The plan was to test the drilling fluids of each of these wells for radioactivity with depth using an LS64 scaling Geiger-Mueller Counter by El Tronics, 2 Incorporated; and, also to check the cuttings commencing at a depth of approximately 3000 feet, where the cuttings were first gathered, for a study of fluorescence when the cuttings are subjected to ultraviolet light

Degradation Resistant Surface Enhanced Raman Spectroscopy Substrates

Raman spectroscopy is employed by NASA, and many others, to detect trace amounts of substances. Unfortunately, the Raman signal is generally too weak to detect when very small, but non-trivial, amounts of molecules are present. One way around this weak signal is to use surface enhanced Raman spectroscopy (SERS). When used as substrates for SERS, metallic nanorods grown using physical vapor deposition (PVD) provide a large enhancement factor to the Raman signal, as much as 1012. However, Silver (Ag) nanorods that give high enhancement suffer from rapid degradation as a function of time and exposure to harsh environment. Exposure to harsh environments is an enormous issue for NASA; considering all environments experienced during space missions will be drastically different from Earth regarding atmosphere pressure, atmosphere composition, and environmental temperature. Au and Ag nanorods suffer from a thermochemical kinetic phenomenon where the surface atoms diffuse and cause the nanostructures to coalesce towards bulk structure. When in bulk, SERS enhancement is lost and the substrate becomes useless. A stable structure for SERS detection is designed through engineering the barriers to surface diffusion. Aluminum (Al) nanorods are forced to undergo surface diffusion through thermal annealing and form rough mounds with a stable terminating oxide layer. When Ag is deposited on top of this Al structure, it becomes kinetically bound and changes to physical structure become impeded. Using this paradigm, samples are grown with varied lengths of Ag and are then characterized using scanning electron microscopy (SEM) and Ultraviolet-Visible spectroscopy. The performance of the samples are then tested using SERS experiments for the detection of trace amounts of rhodamine 6G, a ‘gold standard’ analyte. Characterization shows the effectiveness of the Raman substrates remains stable up to 500°C. Transitioning to basic scientific investigation, next is to strive to isolate the individual impacts of chemical and physical changes to the Ag nanostructure and how they affect the Raman signal. Substrates are compared over the course of a month long experiment to determine the effects of vacuum storage and addressing the effects of chemical adsorbance. Additionally, this was attempted by comparing the signal degradation of Ag nanorods to that of Au, which is known to be chemically inert, allowing for the separation of chemical and physical effects. Although Ag and Au have similar melting points, Ag physically coarsened significantly more. FTIR also showed significant chemical contamination of the Ag, but not Au. A hypothesis is proposed for future investigations into the chemical changes and how they are coupled with and promote the physical changes in nanostructures. Overall, the novel SERS substrate engineered here may enable the detection of trace amounts of molecules in harsh environments and over long timescales. Conditions such as those found on space missions, where substrates will experience months or years of travel, high vacuum environments, and environments of extreme temperatures

Handbook of optical properties for thermal control surfaces, volume III Final report

Handbook of thermal design data and information on thermophysical properties of high performance insulation materials for spacecraft thermal control surface

The Chromospheric Telescope

We introduce the Chromospheric Telescope (ChroTel) at the Observatorio del Teide in Izana on Tenerife as a new multi-wavelength imaging telescope for full-disk synoptic observations of the solar chromosphere. We describe the design of the instrument and summarize its performance during the first one and a half years of operation. We present a method to derive line-of-sight velocity maps of the full solar disk from filtergrams taken in and near the He I infrared line at 10830 \AA.Comment: 12 pages, 9 figure

Energy- and Time-Resolved Liquid-Microjet Photoelectron Spectroscopy of Paradigmatic Aqueous-Phase Polyatomic Molecules

Energy and charge transfer processes in aqueous solution play important roles in biochemical processes, where the mechanisms of such phenomena are affected, and even driven, by aqueous-phase reactant-water interactions. Such processes and interactions have been probed using the Liquid-Jet (LJ)-based Photoelectron Spectroscopy (PES) technique. Energy-tunable, ionizing-radiation sources and the non-resonant, resonant, steady-state, and ultrafast-time-resolved PES techniques have been applied to probe the surface or bulk and valence or core-level electronic, and by extension molecular, structure of several archetypal, highly-soluble, aqueous-phase molecular systems: triiodide, pyrimidine, pyridazine, and pyrazine. The chemically-important, lowest vertical ionization energies and characteristic, atom- and isomer-specific core-level (I 3d/4d, C and N 1s) spectra of the four studied systems are presented here. Ultrafast time-resolution studies of the excited-state dynamics of aqueous pyrazine solutions are also presented. With the help of electronic structure theory and spectral simulations, the experimental triiodide X-ray PES results suggest a near-linear geometric structure and increased asymmetry of the anion in aqueous solution, compared to in ethanol and methanol. This asymmetry was found to be greater at the surface-vacuum interface than in the aqueous solution bulk. Additionally, non-resonant and C and N pre-K-edge resonant X-ray PES experiments were performed on the aqueous diazine molecules, revealing the vertical ionization potentials, bonding character and atomic parentage, intra- and intermolecular charge re-arrangement, and degree of localization of the valence band Molecular Orbitals (MOs). Having measured the ground-state ionization energetics, UV-pump (267 nm), EUV-probe (32.1 nm) femtosecond time-resolved LJ-PES measurements were performed on aqueous pyrazine solutions under Pump-Induced-Space-Charge (PISC) minimized conditions. Global fit analyses of the LJ-PES data revealed an initial 40 ± 20 fs internal conversion (IC) timescale, with subsequent population transfer to lower-lying states occurring in 35 ± 10 ps and 120 ± 30 ps. Slower relaxation behaviors were found in aqueous pyrazine solution in comparison to previously reported gas-phase studies. Associated solvent-induced relaxation mechanisms have been proposed. Furthermore, it is suggested that the relaxation dynamics of aqueous pyrazine are altered when similar experiments are performed under PISC conditions. In general, this thesis highlights the sensitivity of LJ-PES to solution-phase electronic structure, molecular geometries, and dynamic photophysicochemical processes. The experimental results provide the necessary information to enhance the implemented experimental techniques, model general polyatomic molecular behaviors in aqueous solutions, and better understand the photochemical processes that underly numerous real-world applications.Energie- und Ladungsübertragungsprozesse in Lösungen in Wasser spielen eine wichtige Rolle in biochemischen Prozessen, bei denen die Mechanismen solcher Phänomene durch Wechselwirkungen zwischen Reaktanten und Wasser in der wässrigen Phase beeinflusst und sogar angetrieben werden. Solche Prozesse und Wechselwirkungen wurden mit der auf Flüssigkeitsstrahlen (LJ) basierenden Photoelektronenspektroskopie (PES)-Technik untersucht. Energieabstimmbare, ionisierende Strahlungsquellen und die nichtresonanten, resonanten, stationären und ultraschnellen zeitaufgelösten PES-Techniken wurden angewendet, um die Oberfläche oder Masse und die Valenz- oder Kernebene elektronischer und im weiteren Sinne molekularer, Struktur mehrerer archetypischer, hochlöslicher molekularer Systeme in wässriger Phase: Triiodid, Pyrimidin, Pyridazin und Pyrazin. Hier werden die chemisch wichtigen, niedrigsten vertikalen Ionisierungsenergien und charakteristischen, atom- und isomerspezifischen Kernebenenspektren (I 3d/ 4d, C und N 1s) der vier untersuchten Systeme vorgestellt. Außerdem werden ultraschnelle zeitaufgelöste Studien der Dynamiken angeregter Zustände wässriger Pyrazinlösungen vorgestellt. Mit Hilfe der Theorie der elektronischen Struktur und Simulationen von Spektren deuten die experimentellen Triiodid-Röntgen-PES-Ergebnisse auf eine nahezu lineare geometrische Struktur und eine erhöhte Asymmetrie des Anions in wässriger Lösung im Vergleich zu Ethanol und Methanol hin. Diese Asymmetrie wurde an der Oberfläche-Vakuum-Grenzfläche stärker als in der wässrigen Lösungsmasse gefunden. Zusätzlich wurden an den wässrigen Diazinmolekülen nichtresonante und C- und N-K-Pre-Edge resonante XPS Experimente durchgeführt, welche die vertikalen Ionisierungspotentiale, den Bindungscharakter und dessen atomare Abstammung, die intra- und intermolekulare Ladungsumordnung, und den Grad der Lokalisierung der Valenzband-Molekülorbitale (MOs) aufdeckten. Nach der Messung der Grundzustandionisationsenergetik wurden zeitaufgelöste Femtosekunden-LJ-PES-Messungen mit UV-Pump- (267 nm) und EUV-Probepulsen (32,1 nm) an wässrigen Pyrazinlösungen unter minimierter pumpen-induzierter Raumladung (PISC) durchgeführt. Globale Anpassungsanalysen an den LJ-PES-Daten ergaben eine anfängliche Zeitskala für die interne Konvertierung (IC) von 40 ± 20 fs, wobei der anschließende Besetzungstransfer in tiefer gelegene Zustände in 35 ± 10 ps und 120 ± 30 ps erfolgte. Im Vergleich zu vorherigen Gasphasenstudien wurde in wässriger Pyrazinlösung ein langsameres Relaxationsverhalten festgestellt. Es wurden damit verbundene lösungsmittelinduzierte Relaxationsmechanismen vorgeschlagen. Darüber hinaus wird vermutet, dass sich die Relaxationsdynamik von wässrigem Pyrazin verändert, wenn ähnliche Experimente unter PISC-Bedingungen durchgeführt werden. Im Allgemeinen unterstreicht diese Arbeit die Empfindlichkeit von LJ-PES gegenüber der elektronischen Struktur der Lösungsphase, Molekülgeometrien und dynamischen photophysikochemischen Prozessen. Die experimentellen Ergebnisse liefern die notwendigen Informationen, um die implementierten experimentellen Techniken zu verbessern, allgemeine polyatomare molekulare Verhaltensweisen in wässrigen Lösungen zu modellieren und die photochemischen Prozesse, die zahlreichen Anwendungen in der Praxis zugrunde liegen, besser zu verstehen

Shock temperatures in silica glass: Implications for modes of shock-induced deformation, phase transformation, and melting with pressure

Gray body temperatures and emittances of silica glass under shock compression between 10 and 30 GPa are determined. Observed radiative temperatures are higher than computed continuum temperatures for shock-compressed silica glass; however, below ∼26 GPa observed emittances are <0.02. This suggests that fused quartz deforms heterogeneously in this shock pressure range as has been observed in other minerals. Between 10 and 16 GPa, radiative temperatures decrease from 4400 K to 3200 K, whereas above 16–30 GPa, gray body temperatures of ∼3000 K with low emittances are observed. The emittances increase with pressure from 0.02 to 0.9. The pressure range from 10 to 16 GPa coincides with the permanent densification region, while the 16–30 GPa range coincides with the inferred mixed phase region along the silica glass Hugoniot. The differing radiative behaviors may relate to these modes of deformation. Based upon earlier shock recovery experiments and a proposed model of heterogeneous deformation under shock compression, the temperatures associated with low emittances in the mixed phase region probably represent the melting temperature of the high-pressure phase, stishovite, which can be expected to crystallize from a melt in hot zones. Above 20 GPa the melting temperature of stishovite would therefore be 3000 K±200 K and almost independent of pressure to 30 GPa. The effects of pressure on melting relations for the system SiO_2–Mg_2SiO_4 are considered together with the proposed stishovite melting curve and suggested maximum solidus temperatures within the mantle of ∼2370 K at 12.5 GPa and ∼2530 K at 20.0 GPa. Using the proposed stishovite melting temperatures Tm and estimates of upper mantle temperatures T, the effective viscosity, which can be considered a function of the homologous temperature T/T_m, appears to remain nearly constant from 200 to 600 km depth in the Earth

Light-trapping and Superhydrophobic Plant Surfaces : Optimized Multifunctional Biomimetic Surfaces for Solar Cells

In a process spanning over 400 millions years of evolution, plants have developed multifunctional surfaces that are highly adapted to environmental conditions. Nature provides several millions varieties of plant species resulting in an extreme diversity of functionalized surfaces, which are often characterized by a hierarchically structured architecture. These sophisticated surface designs may protect leaves against contaminations or mechanical stress, play an important role in the plant´s hydrological balance, protect the metabolic system against harmful radiation or support the optical attractiveness of flowers. The architecture and chemistry of these surfaces determine their functionalities. Analysis of these optimized biological surfaces could be the key to optimizing technical surfaces. Over the last years these functionalized plant surfaces have often been used as models for the development of, e.g. self-cleaning (Lotus-Effect) or air retaining (Salvinia-Effect) biomimetic surfaces. Yet the technical potential of the optical properties of plant surfaces has only been examined marginally, especially for the optimization of light-trapping and water-repellent solar cells. Therefore this study analyses the optical and wetting properties of hierarchically structured leaf and flower surfaces as well as their technical replicas. As a result of this work a new, light-trapping and superhydrophobic surface architecture for the optimization of high efficiency solar cells is presented

Laser Precision Spectroscopy on Hydrogen Isotopologues: Tritiated molecules and vibrationally excited H2

Hydrogen molecules plays an important role in research of fundamental physics as the subject of this thesis. H2 is the simplest neutral molecule consisting of two protons and two electrons. Because of its simplicity, it serves as a benchmark molecule for testing quantum chemical theories. Most of the precision measurements on molecular hydrogens are performed at the low lying ro-vibrational states of the stable isotopologues, H2, HD and D2. This thesis will present two distinct topics of precision spectroscopic measurement, 1) the heavier radioactive tritium-containing isotopologues of molecular hydrogen, HT, DT and T2 and 2) highly ro-vibrationally excited levels and quasi-bound state of molecular hydrogen to test theoretical calculations, in particular on the mass-dependent terms and the potential energy curves at large internuclear distances. In Chapter 1, a brief introduction of the theoretical framework to obtain the molecular hydrogen level energies is presented. The mass-dependent terms and the sensitivity of long-range potential energy curve at different ro-vibrational states will be discussed. Chapters 2 and 3 focus on the measurement of the vibrational interval in three tritium-containing isotopologues of molecular hydrogen. Spectroscopic studies on the static tritium-containing isotopologues gas samples with are performed using Coherent Anti-Stokes Raman Spectroscopy to measure the fundamental vibrational interval (v = 0 → 1). Several Q-branch lines (ΔJ = 0) of tritium-containing species were measured at 10^−4 cm^−1 uncertainty, presenting an over 100-times improvement. The experimental measurements on tritium-containing species were compared to results of non-adiabatic perturbation theory (NAPT) produced by Polish theorists. Chapters 4 - 7 cover the studies of highly vibrationally-excited and quasibound states of the ground electronic state of H2. The preparation of excited ro-vibrationally excited states in the ground electronic state of H2 is by the photolysis of H2S at 281.8 nm. In Chapter 5, the two highest vibrational levels v = 13 and v = 14 are probed through Doppler-free two-photon spectroscopy of F 1Σ+g - X 1Σ+g transitions. The assignments of the transitions are verified by recording excitation spectra from the populated F-states. The combination differences of transitions from v = 13 and v = 11 levels yield the vibrational intervals in the ground electronic state H2. A comparison with results from theoretical calculations produces good agreement. In Chapter 6 and 7, five quasi-bound states of H2 with lifetime in the range of 1 ns to 10 μs are probed through F - X transitions as well. The larger signal strength of these transitions compared to the other bound state transitions is explained by the enhanced Franck-Condon factor. Measurements of the F-X Q-branch and the S/O-branch (ΔJ = ±2) transitions connect all 5 observed quasi-bound resonances to give the X1Σ+gstate level intervals. The NAPT calculation scheme are extended to calculate the quasi-bound resonance energies. The calculated quasi-bound level intervals agree well with the observation