Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
The Luminous Power Of Accretion Disks In Active Galactic Nuclei, Imogen Jade Courtney
The Luminous Power Of Accretion Disks In Active Galactic Nuclei, Imogen Jade Courtney
Honors Theses
Active Galactic Nuclei (AGN) are the most luminous long-lived objects in the universe. The phenomenon of the immense luminosities we observe for AGN has interested physicists and astronomers for over a century and continues to fascinate scientists today. The work in this thesis aims to provide an introductory exploration of this phenomenon. This thesis uses a simple model of AGN accretion disks that was developed under the standard disk model proposed by Shakura & Sunyev in 1973 under the simplest assumptions. The model accurately demonstrates how physical parameters, such as the temperature, radiative flux, luminosity, and spectra, scale through an …
Study Of Deexcitation Intensities To The K-Shell In Iron 55, Eric Helgemo
Study Of Deexcitation Intensities To The K-Shell In Iron 55, Eric Helgemo
Honors Theses
55Fe radioactive sources are used for x-ray calibration due to the long half-lives of 2.73 years and the optimal energies of the peaks. The source used in the experiment was generated using Western Michigan University’s Tandem Van de Graff accelerator to produce a 6 MeV proton beam which induced a 55Mn(p, n)55Fe reaction on a 10 μm 55Mn target. The emissions from this target were then measured using a silicon lithium drift x-ray detector to determine the number of instances of deexcitation through kα and kβ modes. The preliminary data discussed showed a lower relative deexcitation rate of 6.67 between …
Radiative Double Electron Capture By Ions In Collisions With Gas Targets, Charles Taylor
Radiative Double Electron Capture By Ions In Collisions With Gas Targets, Charles Taylor
Honors Theses
Radiative double electron capture (RDEC) is a two-step quantum process where two electrons are captured from the target gas to the projectile ion beam with a simultaneous emission of a single photon. The projectile ion beam was obtained from the tandem Van de Graaff accelerator at Western Michigan University. The projectile beam used is fully and partially ionized fluorine 9+, and 8+ in collision with highly pure nitrogen gas. The objective of the research is to observe RDEC from x ray detection using time to amplitude converters (TACs) that look for coincidences between x rays and particles. The signal from …
The Proton Veto Project At Wmu/Msu, Justin Swaim
The Proton Veto Project At Wmu/Msu, Justin Swaim
Honors Theses
The Proton Veto Wall (VW) is a charged particle detector designed and built at Western Michigan University for use at the National Superconducting Cyclotron Laboratory at Michigan State University. The VW assists the Large Area Neutron Array (LANA) with discriminating between charged particles detected via proton recoil in the scintillating material and charged particles detected from heavy ion collisions produced in the laboratory. Twenty five Eljen-200 plastic organic scintillators are arranged in a vertical position with photomultiplier tubes (PMTs) mounted to either end. The detector sits directly in front of LANA on a large stand that was assembled using T-slotted …
Type 1a Supernova Models And Galactic Chemical Evolution, Spencer Henning
Type 1a Supernova Models And Galactic Chemical Evolution, Spencer Henning
Honors Theses
Multiple models of type Ia supernovae are discussed, as well as the properties of white dwarf formation, electron degeneracy pressure, nucleosynthesis, and galactic chemical evolution (GCE). A GCE computer model is used to produce nuclear abundance data corresponding to Chandra (W7) and sub-Chandra (WDD2) type Ia supernovae models for Ca, Sc, Ti, V, Cr, and Mn nuclei. Overall, a trend was found indicating that the WDD2 model had greater [x/Fe] abundance values than the W7 model at the end time of the model. Additionally, each model fit within total observed data, but observed data filtered to highlight white dwarf stars …
Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey
Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey
Honors Theses
The requirements of low cost and high-cost temperature corrosion resistance for interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of stainless steel plates with homogenous coatings of CrAIN. The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas and N as reactive gas. The Cr/A1 composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800°C. The composition of the coated plates and the …
Angle-Resolved Study Of Ar 2p₁/₂,₃/₂⁻1Ns,D Resonant Auger Decay, Marc Andrew Humphrey
Angle-Resolved Study Of Ar 2p₁/₂,₃/₂⁻1Ns,D Resonant Auger Decay, Marc Andrew Humphrey
Honors Theses
Angle-resolved measurements of the Ar 2p1/2,3/2-14s,3d,4d and 2p3/2-14s,3d,4d resonant Auger transitions have been carried out using photons from an undulator beamline at the Advanced Light Source of Lawrence Berkeley National Laboratory. The intensity distributions and angular distribution anisotropy (β) parameters have been reported for nearly all of the possible 3p4nl final ionic states. These results further verify the predictions of the spectator model for the 2p1/2,3/2-14s resonances and the subsequent breakdown of this model for the 2p1/2,3/2-13d and 2p1/2,3/2-14d relative intensities. This work …
Combination Effects Of Irradiation And Chemical Doping On High Temperature Superconductors, Russell J. Fedewa
Combination Effects Of Irradiation And Chemical Doping On High Temperature Superconductors, Russell J. Fedewa
Honors Theses
The goal of this project is to investigate some methods that improve the critical transport current in high temperature superconductors. A superconductor is a material which can allow an electrical current to flow through it with no resistance. This makes them ideal for a wide variety of applications. Most of the present use is in science or medicine, and show promise in computer circuitry materials and electromagnetic trains. This experiment explores a means of increasing the critical current, the maximum amount of electric current that can pass, and which at present is too low to permit the use of superconductors …
Design And Construction Of A Lithium Vapor Oven, Corey A. Leon
Design And Construction Of A Lithium Vapor Oven, Corey A. Leon
Honors Theses
A lithium vapor oven to be used as a source of lithium target atoms in atomic collision experiments was designed and constructed. The oven was installed in the beamline of the Van de Graaff accelerator at Western Michigan University. Test results indicated the oven produced a diffuse cloud of evaporated lithium instead of the intended concentrated jet spray. Recommendations concerning the design are made for future efforts.
Polarization Of Compton-Scattered Gamma Rays, James G. Hudson
Polarization Of Compton-Scattered Gamma Rays, James G. Hudson
Honors Theses
Intermediate energy photons (approximately 0.2 mev. to 10 mev.) interact with matter of low atomic number principally through a process called the Compton effect. This process is an inelastic collision of a photon with a free electron at rest. Using the principles of conservation of energy and conservation of momentum the energy of the scattered photon can be found in terms of the incident photon energy and the angle through which it is scattered. The energy of this scattered photon is then given by E1=(EO)/(1+α(1-cos θ)) where EO is the energy of the incoming photon, …