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Full-Text Articles in Physics

Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl Oct 2019

Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl

Physics Theses & Dissertations

The plasma processing of superconducting radio-frequency (SRF) cavities has shown significant promise as a complementary or possible replacement for the current wet etch processes. Empirical relationships between the user-controlled external parameters and the effectiveness of Reactive Ion Etching (RIE) for the removal of surface layers of bulk niobium have been previously established. However, a lack of a physical description of the etching discharge, particularly as the external parameters are varied, limits the development of this technology. A full understanding of how these external parameters affect both the amount of material removed and the physical properties of the plasma would aid …


Validation Of Neutrino Energy Estimation Using Electron Scattering Data, Mariana Khachatryan Oct 2019

Validation Of Neutrino Energy Estimation Using Electron Scattering Data, Mariana Khachatryan

Physics Theses & Dissertations

To study neutrino oscillations, the knowledge of the initial neutrino energy is required. This energy cannot be determined directly because neutrino beams have a broad energy distribution. Instead, the initial energy for each event is estimated from the final state particles of a neutrino-nucleus interaction using two main approaches. It can be determined either from the total energy of all the final state particles or, if the neutrino scatters quasi-elastically from a bound nucleon, then the initial energy can be calculated approximately using the scattered angle and energy of the outgoing charged lepton. This requires a detailed understanding of neutrino-nucleus …


Effect Of Alkali On The Efficiency And Reliability Of Cu(In,Ga)Se2 Solar Cells, Shankar Karki Apr 2019

Effect Of Alkali On The Efficiency And Reliability Of Cu(In,Ga)Se2 Solar Cells, Shankar Karki

Physics Theses & Dissertations

The incorporation of alkali metal has contributed tremendously in a bid to realize greater than 20% efficient Cu(In,Ga)Se2(CIGS) solar cells. Achieving high efficiency is one key parameter for the success of a photovoltaic technology but so is its long-term stability. In this thesis, the relationship between the performance of alkali treated Cu(In,Ga)Se2 solar cells and their physicochemical, electronic and structural properties are explored through a comparative study between standard devices and alkali (K, Rb) treated devices. The alkali treated devices tend to have a lower concentration of Ev+0.98 eV trap, higher majority carrier concentration and …


Optical Excitation Of Metastable Krypton And Photoassociative Spectroscopy Of Ultracold Rbar, Grady R. White Apr 2019

Optical Excitation Of Metastable Krypton And Photoassociative Spectroscopy Of Ultracold Rbar, Grady R. White

Physics Theses & Dissertations

In this presentation, we discuss results from two separate bodies of work. In the first, we investigate all-optical excitation methods to produce metastable-state krypton. The high energies required to excite rare gases out of their ground state present a unique challenge in the context of laser experiments. Laser physics work with rare gases often relies on excitation within an RF discharge. All-optical excitation is a promising replacement for RF discharges, avoids problems caused by ion production and may eventually allow for higher efficiencies. We examine three separate methods of all-optical metastable-state production: using an ArF excimer laser, using the third …