Physics: Theses

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    Deuterium-Deuterium Fusion Reactions in the Houghton College Cyclotron
    (Houghton College, 2022-05-12) Bowman, Joshua
    The Houghton College Cyclotron is a miniature particle accelerator that uses two “dee” shaped hollow electrodes, of 15.6 cm radius, to accelerate ions across a gap with an alternating RF potential difference of a few thousand volts at a frequency of 5.831 MHz. As an ion accelerates, an up to 1.13 T magnetic field keeps it on a circular path that spirals outward, allowing the ion to accelerate multiple times using the same electric potential. In this experiment, deuterons were ionized by electrons from a filament and accelerated, with a current of about 20 nA and an approximate energy of 4.8 keV, into a copper target at a radius of 5.54 cm where they embedded themselves. Later deuterons striking the embedded deuterons caused the D(d,n)3He reaction which produced neutrons. A plastic scintillator detector counted the neutrons that penetrated the chamber walls. An increase of 7913±587 counts or 158±12 counts per minute was detected when the beam was turned on. This is a significant milestone for the Houghton College Cyclotron as it is the first nuclear reaction that this cyclotron has successfully generated.
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    An Experiment to Simulate the Trapping and Detection of Radioactive Isotopes Produced In ICF Implosions
    (Houghton College, 2022-01-28) Christensen, Micah J.
    It may be possible to measure the low energy nuclear cross sections of light ion reactions by trapping the reaction products from an ICF implosion and detecting their beta decays. To test this idea, an “exploding wire” experiment has been designed to simulate the expanding gas released in an ICF event. A copper plated tungsten foil was inserted into a vacuum chamber and activated with a deuteron beam via 65Cu(d,p)66Cu. A current pulse then vaporized the copper to create an expanding radioactive gas, simulating the gas behavior in the ICF target chamber following the laser shot. Attempts were made to capture some gas and detect the 66Cu beta decays using two trap designs, one using a getter foil and the other a turbopump. Results were obtained with both trap designs, using the Short-Lived Isotope Counting System (SLICS) consisting of plastic scintillator phoswich detectors and fast electronics to identify and count the beta particles.
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    Consistent Operation of the Houghton College Deposition Chamber
    (Houghton College, 2021-06-07) Malone, Jared
    An apparatus constructed to consistently and systematically deposit thin metal films using thermionic emission has been refined. A turbo pump lowers the base pressure of the deposition chamber to 10-6 Torr. Thermionic emission is achieved via current passing through a tungsten filament that is held at -4 kV relative to the desired deposition material. Multiple refinements were made to the apparatus' high voltage circuit to improve the consistency of operation, primarily the securing of multiple connections within the circuit. Additionally, two 2 kV microwave transformers, and four diodes used to produce a doubling rectifier were replaced, and a capacitor bank was added to further refine the output of the forementioned circuit. While production of a thin metal film has yet to be achieved, the high voltage power supply is capable of consistently maintaining a high negative potential to facilitate the production process. Future work and modifications of the apparatus are also discussed.
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    Inertial Confinement Fusion as a Tool to Study Fundamental Nuclear Science
    (Houghton College, 2021-05-12) Kowalewski, Tyler
    Inertial confinement fusion may possibly be used to make fundamental nuclear science measurements of low energy light ion cross-sections of interest in astrophysics and fusion research. The feasibility of collecting and counting the beta decay of the reaction products (half-life 20 ms to 20 s) in the expanding neutral gas after the ICF shot is being studied using a special vacuum system that allows a radioactive gas to be released, trapped, and counted in situ using different techniques. Initial experiments have used a turbopump to trap the gas in the foreline, where it can be counted by a 4π phoswich beta detector. The construction and simulation of this detector, tests using 41Ar gas produced via the 40Ar(d,p)41Ar reaction, and an OMEGA laser ride along experiment to measure background rates from milliseconds to seconds after a high yield D-T laser shot will be described.
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    Design, Construction, and Testing of the Return Portion of a Closed Return Wind Tunnel
    (Houghton College, 2020-09-16) Langa, Bernardo Jr.
    A low-speed closed-return wind tunnel is being designed and built at Houghton College. Preliminary efforts focused on choosing the layout and appropriately sizing the tunnel. Once this work was complete, individual components could be designed and built. This thesis will discuss detailed design, construction, and preliminary testing of critical components in the return portion of the wind tunnel: a 90-degree corner, the fan, and a diffuser. Corners are used in the wind tunnel to turn the flow so that the tunnel forms one continuous loop. To provide flow, a fan is utilized. Lastly, the diffusers are used to decrease the flow velocity in all regions except for where testing is taking place. Test results will be shown and future work discussed.