Physics: Theses
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- ItemConstructing an X-Ray Diffractometer for the Analysis of Thin Metal Films at Houghton University(Houghton University, 2025-05-05) Fall, Owen D.Houghton University is making an X-ray diffractometer to analyze thin metal films. X-rays are produced in a Norelco diffraction tube and detected by a Vernier Geiger tube. The angular positions of the detector and sample are controlled by stepper motors driving around a semicircular stage and are monitored by two rotary encoders each. The motors rotate at 0.68 m°/step, and there are 22.5 m°/encoder position. The sample is aligned to the axis of rotation with a linear stage. A Teensy 4.1 microcontroller controls the system via a Processing interface. Motor and encoder tests found that the angular distance between encoder positions is not uniform. An array of the number of steps between each encoder position was made for the sample and detector, which allows their angular position to be precisely known.
- ItemCan a Radar Emulator be used to Identify Simulated Pre-Tornadic Small-Scale Vorticity?(Houghton University, 2025-05-05) Harley, NoahTornadoes are largely unpredictable severe weather events that are chaotic in nature. Much of this unpredictability stems from a lack of specific knowledge regarding the process of tornadogenesis. This thesis describes a proposed investigation of pre-tornadic, surfacebased, small-scale vorticity present in the high-resolution Cloud Model 1 numerical convective simulation of the May 24, 2011, El Reno tornadic supercell. The radar emulator RSim will be used to sample the simulated storm using different radar wavelengths, range resolutions, azimuthal resolutions, beamwidths, and other parameters similar to real-world radar sampling strategies. This will potentially allow scanning radar parameters to be optimized, enabling future field campaigns to test for the presence of this pre-tornadic phenomenon. The collaboration would include researchers from the Ohio State University, the University of Wisconsin-Madison, and the University of Oklahoma.
- ItemHoughton University’s Phase-Shifting Laser Interferometer for the Study of Thin Metal Films(Houghton University, 2025-05-05) Yelle, LukeA modified Twyman-Green phase-shifting laser interferometer was built by Houghton University to determine the thickness of thin metal films. A 635 nm beam is split by a cube beam splitter. Lenses expand and culminate the beams to a diameter of 83 mm. One beam reflects off the thin film sample. The other reflects off a 10 cm diameter, 𝜆10 flat, phase-shifting reference mirror moving via piezoelectric ceramic stacks, controlled by an Arduino. Both are then combined to form an interference pattern on a screen. The intensity of a given point on the interference pattern changes sinusoidally with the change of position of the reference mirror. A set of pictures is taken at different reference positions by an HP high-definition camera and is then processed by a Processing code. Each pixel of the image set is fit to determine its effective intensity phase shift, which is then used to map the topography of the film surface.
- ItemA PARITY VIOLATION TRANSMISSION EXPERIMENT FOR UNDERGRADUATE LABORATORIES(Houghton University, 2024-05-03) Kennel, LeviBecause there are currently no published weak interaction parity violation experiments specifically for undergraduate laboratories, a simple parity violation experiment is being developed using circularly polarized gamma rays. A 60Co source will be placed on one side of an electromagnet, so that the circularly polarized gamma rays emitted opposite the beta particles will pass through the electromagnet. A NaI detector detects the number of gamma rays that pass through the electromagnet, and a silicon detector detects in coincidence beta particles opposite the gamma rays. The number of 𝛾𝛽 coincidence events will be measured when the electromagnet is polarized both parallel and antiparallel to the gamma rays — an asymmetry between the number of coincidence events for each orientation would show that parity is violated.
- ItemX-RAY DIFFRACTOMETER FOR THIN FILM ANALYSIS AT HOUGHTON UNIVERSITY(Houghton University, 2024-05-03) Davie, Nathaniel T.A Bragg-Brentano theta-2 theta x-ray Diffractometer was advanced towards completion in construction at Houghton University as a means to measure the lattice structure and sub-atomic spacing of thin films and small crystals. The x-ray Diffractometer (XRD) uses angles of diffracted characteristic x-rays to analyze the space between cells. The XRD is dependent on the derivation and application of the mathematical equation denoted by Bragg’s Law, stating the angle of large quantities of x-rays being delayed by integer multiples such that the wavefronts are lined up in shape, called constructive interference. The Houghton XRD machine was inherited from previous students ranging back 14 years. Preliminary tests using a Silicon thin film and a single Sodium-Iodide lab-grown crystal have been conducted, and further, intensive tests are aimed to be conducted in the fall of 2024. The analysis conducted at Houghton University by the XRD can offer a range of data regarding the mechanical, physical, and electrodynamic properties of thin films, resulting in optimized application of the thin films themselves.