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Full-Text Articles in Physical Sciences and Mathematics
Development And Implementation Of A Pressure-Temperature Control System For The Physical Vapor Deposition Of Copper And Niobium From A Molybdenum Filament In The Development Of Superconducting 3d Printed Rf Cavity Particle Accelerators, Chandler J. Fleuette
Student Research Projects
This report covers the development of the pressure-temperature control system used in the production of small superconducting RF cavities for particle accelerators. To test the validity of the created program, a model for the process was created and tested. The model was used to fine tune the control system before integrating it into the lab. The end goal of the control system is to measure the pressure inside of a deposition vacuum chamber, convert that pressure to a temperature, and use that temperature in tandem with a PID controller to control the current passing though a molybdenum filament which is …
Development And Implementation Of A Pressure-Temperature Control System For The Physical Vapor Deposition Of Copper And Niobium From A Molybdenum Filament In The Development Of Superconducting 3d Printed Rf Cavity Particle Accelerators, Chandler J. Fleuette
Honors Theses and Capstones
This report covers the development of the pressure-temperature control system used in the production of small superconducting RF cavities for particle accelerators. To test the validity of the created program, a model for the process was created and tested. The model was used to fine tune the control system before integrating it into the lab. The end goal of the control system is to measure the pressure inside of a deposition vacuum chamber, convert that pressure to a temperature, and use that temperature in tandem with a PID controller to control the current passing though a molybdenum filament which is …
Quantifying Electron Precipitation In The Van Allen Radiation Belts, Timothy Raeder
Quantifying Electron Precipitation In The Van Allen Radiation Belts, Timothy Raeder
Honors Theses and Capstones
The spatial and temporal distribution of high energy electron precipitation from the Van Allen radiation belts is not currently well-understood. The FIREBIRD-II mission (2015-present) and the Van Allen Probes (2012-2019) provide a unique opportunity to examine the behaviors and drivers of high energy electron precipitation. This study quantifies electron precipitation observed by FIREBIRD-II as a function of radial distance (L-shell), magnetic local time (MLT), hemisphere, and geomagnetic indices (Kp). Electron precipitation was observed to peak at L-shell 4.5-5. Regions of elevated electron precipitation were identified at L-shell 4-6 at dawn (MLT 6-9) and dusk (MLT 15-21). Hemisphere filtering indicated very …
Re-Analysis Of The World Data On The Emc Effect And Extrapolation To Nuclear Matter, Stacy E. Karthas
Re-Analysis Of The World Data On The Emc Effect And Extrapolation To Nuclear Matter, Stacy E. Karthas
Honors Theses and Capstones
The EMC effect has been investigated by physicists over the past 30 years since it was discovered at CERN. This effect shows that the internal nucleon structure varies when in the nuclear medium. Data from SLAC E139 and JLab E03 103 were studied with the Coulomb correction and directly compared. The Coulomb distortion had a greater impact on the JLab data due to slightly lower energies and different kinematics. The EMC ratio was found to have a dependence on a kinematic variable, which was removed when Coulomb corrections were applied. The methodology was developed to apply Coulomb corrections, which had …
Forcing Mutual Coherence In Diode Laser Stacks, Jonathan R. Wurtz
Forcing Mutual Coherence In Diode Laser Stacks, Jonathan R. Wurtz
Honors Theses and Capstones
This paper will discuss both theoretical and experimental attempts to improve the spatial beam quality of diode laser stacks using an external optical system. An overview and derivation of the mathematics of both the optical system and diode lasers will be discussed. The experimental setup will be presented, as well as the fundamental theoretical and experimental results that suggest the external optical system used for this thesis fails to improve the beam quality of a diode laser stack.
A Statistical Analysis Of Electromagnetic Ion Cyclotron (Emic) Waves And Their Correlation To The 11-Year Solar Cycle, Erik A. Lindgren
A Statistical Analysis Of Electromagnetic Ion Cyclotron (Emic) Waves And Their Correlation To The 11-Year Solar Cycle, Erik A. Lindgren
Honors Theses and Capstones
This thesis presents a statistical analysis of EMIC waves measured at Halley Research Station from 2008 through 2012. An introduction covering the origin of and theory behind EMIC waves is provided, along with a background covering previous statistical research regarding EMIC waves. Guidelines regarding EMIC wave definition and analysis are described along with examples of how they were used. The data shows an increase in the total number of EMIC waves as well as the number and percentage of EMIC waves with maximum frequency above 1 Hz during the 5-year period. The results suggest that the total number of EMIC …
Characterizing Electrons In Primary And Secondary Magnetic Islands During Magnetic Reconnection, Jason Shuster
Characterizing Electrons In Primary And Secondary Magnetic Islands During Magnetic Reconnection, Jason Shuster
Honors Theses and Capstones
The physics underlying particle-in-cell simulations that are widely employed in studying plasma dynamics are reviewed. Results from a two-dimensional particle-in-cell simulation of fully kinetic, undriven, collisionless magnetic reconnection are studied to compare the electrons in a primary magnetic island formed from an ion current sheet and the electrons in a secondary island formed in an electron current layer. We find that the secondary island is born with a strong out-of-plane current density due to localized peaks in the electron density and out-of-plane electron velocity; the secondary island retains these features as it evolves, distinguishing it from the primary island. For …
Metastable Anions Of Dinitrobenzene: Resonances For Electron Attachment And Kinetic Energy Release, A. Mauracher, S. Denifl, A. Edtbauer, M. Hager, M. Probst, Olof E. Echt, T. D. Maerk, P. Scheier, T. A. Field, K. Graupner
Metastable Anions Of Dinitrobenzene: Resonances For Electron Attachment And Kinetic Energy Release, A. Mauracher, S. Denifl, A. Edtbauer, M. Hager, M. Probst, Olof E. Echt, T. D. Maerk, P. Scheier, T. A. Field, K. Graupner
Physics & Astronomy
Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO(2)) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)(-) features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)(-) offers a rare …
Near-Infrared Photoabsorption By C(60) Dianions In A Storage Ring, U. Kadhane, J. U. Andersen, E. Bonderup, B. Concina, P. Hvelplund, M. Kirketerp, B. Suhr, B. Liu, S. Bronsted Nielsen, S. Panja, J. Rangama, K. Stochkel, S. Tomita
Near-Infrared Photoabsorption By C(60) Dianions In A Storage Ring, U. Kadhane, J. U. Andersen, E. Bonderup, B. Concina, P. Hvelplund, M. Kirketerp, B. Suhr, B. Liu, S. Bronsted Nielsen, S. Panja, J. Rangama, K. Stochkel, S. Tomita
Physics & Astronomy
We present a detailed study of the electronic structure and the stability of C(60) dianions in the gas phase. Monoanions were extracted from a plasma source and converted to dianions by electron transfer in a Na vapor cell. The dianions were then stored in an electrostatic ring, and their near-infrared absorption spectrum was measured by observation of laser induced electron detachment. From the time dependence of the detachment after photon absorption, we conclude that the reaction has contributions from both direct electron tunneling to the continuum and vibrationally assisted tunneling after internal conversion. This implies that the height of the …
Formation Of Even-Numbered Hydrogen Cluster Cations In Ultracold Helium Droplets, S. Jaksch, A. Mauracher, A. Bacher, S. Denifl, F. Ferreira De Silva, H. Schoebel, Olof E. Echt, T. D. Maerk, M. Probst, D. K. Bohme, P. Scheier
Formation Of Even-Numbered Hydrogen Cluster Cations In Ultracold Helium Droplets, S. Jaksch, A. Mauracher, A. Bacher, S. Denifl, F. Ferreira De Silva, H. Schoebel, Olof E. Echt, T. D. Maerk, M. Probst, D. K. Bohme, P. Scheier
Physics & Astronomy
Neutral hydrogen clusters are grown in ultracold helium nanodroplets by successive pickup of hydrogen molecules. Even-numbered hydrogen cluster cations are observed upon electron-impact ionization with and without attached helium atoms and in addition to the familiar odd-numbered H(n)(+). The helium matrix affects the fragmentation dynamics that usually lead to the formation of overwhelmingly odd-numbered H(n)(+). The use of high-resolution mass spectrometry allows the unambiguous identification of even-numbered H(n)(+) up to n congruent to 120 by their mass excess that distinguishes them from He(n)(+), mixed He(m)H(n)(+), and background ions. The large range in size of these hydrogen cluster ions is unprecedented, …
Lifetimes Of C-60(2-) And C-70(2-) Dianions In A Storage Ring, S. Tomita, J. U. Andersen, H. Cederquist, B. Concina, Olof E. Echt, J. S. Forster, K. Hansen, B. A. Huber, P. Hvelplund, J. Jensen, B. Liu, B. Manil, L. Maunoury
Lifetimes Of C-60(2-) And C-70(2-) Dianions In A Storage Ring, S. Tomita, J. U. Andersen, H. Cederquist, B. Concina, Olof E. Echt, J. S. Forster, K. Hansen, B. A. Huber, P. Hvelplund, J. Jensen, B. Liu, B. Manil, L. Maunoury
Physics & Astronomy
C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb …
Simulation Of Charged Particle Trajectories In The Neutron Decay Correlation Experiment Abba, D. Desai, G. Greene, R. Mahurin, D. Bowman, John R. Calarco
Simulation Of Charged Particle Trajectories In The Neutron Decay Correlation Experiment Abba, D. Desai, G. Greene, R. Mahurin, D. Bowman, John R. Calarco
Physics & Astronomy
The proposed neutron decay correlation experiment, abBA, will directly detect the direction of emission of decay protons and electrons as well as providing spectroscopic information for both particles. In order to provide this information, the abBA experiment incorporates spatially varying electric and magnetic fields. We report on detailed simulations of the decay particle trajectories in order to assess the impact of various systematic effects on the experimental observables. These include among others; adiabaticity of particle orbits, tracking of orbits, reversal of low energy protons due to inhomogeneous electric field, and accuracy of proton time of flight measurements. Several simulation methods …
Mechanisms And Dynamics Of The Metastable Decay In Ar-2(+), J. Fedor, K. Gluch, R. Parajuli, S. Matt-Leubner, Olof E. Echt, P. Scheier, T. D. Mark
Mechanisms And Dynamics Of The Metastable Decay In Ar-2(+), J. Fedor, K. Gluch, R. Parajuli, S. Matt-Leubner, Olof E. Echt, P. Scheier, T. D. Mark
Physics & Astronomy
A detailed experimental as well as theoretical investigation of the properties of the metastable dissociation Ar-2(+)-->Ar++Ar is presented. The mass-analyzed ion kinetic energy (MIKE) scan technique has been performed using a three sector field mass spectrometer. The possible mechanisms of the metastability of Ar-2(+) have been examined and the observed decay process is assigned to the II(1/2)(u)-->I(1/2)(g) bound to continuum radiative transition, in agreement with earlier work. The calculation of the theoretical shape of the kinetic energy release distribution of fragment ions allowed us to construct the theoretical MIKE peak and compare it with the raw experimental data. …
High-Resolution Kinetic Energy Release Distributions And Dissociation Energies For Fullerene Ions C(N)(+), 42 <= N <= 90, K. Gluch, S. Matt-Leubner, Olof E. Echt, B. Concina, P. Scheier, T. D. Mark
High-Resolution Kinetic Energy Release Distributions And Dissociation Energies For Fullerene Ions C(N)(+), 42 <= N <= 90, K. Gluch, S. Matt-Leubner, Olof E. Echt, B. Concina, P. Scheier, T. D. Mark
Physics & Astronomy
We have measured the kinetic energy released in the unimolecular dissociation of fullerene ions, C(n)(+)-->C(n-2)(+)+C(2), for sizes 42less than or equal tonless than or equal to90. A three-sector-field mass spectrometer equipped with two electric sectors has been used in order to ensure that contributions from isotopomers of different masses do not distort the experimental kinetic energy release distributions. We apply the concept of microcanonical temperature to derive from these data the dissociation energies of fullerene cations. They are converted to dissociation energies of neutral fullerenes with help of published adiabatic ionization energies. The results are compared with literature values. …
High Resolution Measurements Of Kinetic Energy Release Distributions Of Neon, Argon, And Krypton Cluster Ions Using A Three Sector Field Mass Spectrometer, K. Gluch, S. Matt-Leubner, L. Michalak, Olof E. Echt, A. Stamatovic, P. Scheier, T. D. Mark
High Resolution Measurements Of Kinetic Energy Release Distributions Of Neon, Argon, And Krypton Cluster Ions Using A Three Sector Field Mass Spectrometer, K. Gluch, S. Matt-Leubner, L. Michalak, Olof E. Echt, A. Stamatovic, P. Scheier, T. D. Mark
Physics & Astronomy
Using a newly constructed three sector field mass spectrometer (resulting in a BE1E2 field configuration) we have measured the kinetic energy release distributions of neon, argon, and krypton cluster ions. In the present study we used the first two sectors, B and E1, constituting a high resolution mass spectrometer, to select the parent ions in terms of mass, charge, and energy, and studied the decay of those ions in the third field free region. Due to the improved mass resolution we were able to extend earlier studies carried out with a two sector field machine, where an upper size limit …
Kinetic-Energy Release In Coulomb Explosion Of Metastable C3h52+, K. Gluch, J. Fedor, S. Matt-Leubner, Olof E. Echt, A. Stamatovic, M. Probst, P. Scheier, T. D. Mark
Kinetic-Energy Release In Coulomb Explosion Of Metastable C3h52+, K. Gluch, J. Fedor, S. Matt-Leubner, Olof E. Echt, A. Stamatovic, M. Probst, P. Scheier, T. D. Mark
Physics & Astronomy
C3H52+, formed by electron impact ionization of propane, undergoes metastable decay into C2H2++CH3+. We have monitored this reaction in a magnetic mass spectrometer of reversed geometry that is equipped with two electric sectors (BEE geometry). Three different techniques were applied to identify the fragment ions and determine the kinetic-energy release (KER) of spontaneous Coulomb explosion of C3H52+ in the second and third field free regions of the mass spectrometer. The KER distribution is very narrow, with a width of about 3% [root-mean square standard deviation]. An average KER of 4.58+/-0.15 eV is derived from the distribution. High level ab initio …
Kinetic Energy Release In Electron-Induced Decay Reactions Of Molecular Ions: C3h8+ And C3h7+, S. Matt, Olof E. Echt, A. Stamatovic, T. D. Mark
Kinetic Energy Release In Electron-Induced Decay Reactions Of Molecular Ions: C3h8+ And C3h7+, S. Matt, Olof E. Echt, A. Stamatovic, T. D. Mark
Physics & Astronomy
We have measured the kinetic energy release (KER) distributions for electron-induced dissociation of mass-selected molecular parent and fragment ions of propane. They are compared with distributions determined for spontaneous (metastable) dissociation. The average KER for induced dissociation of C3H8+ into C3H7+ is 13.2 +/- 1.2 meV, about 42% larger than for the spontaneous reaction. This large difference is attributed to the dramatically reduced time at which the induced reaction can be sampled. In contrast, the KER for dissociation of C3H7+ into C3H5+, which is characterized by a large reverse activation energy, is hardly affected by the experimental time scale. (C) …