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- ItemA Temperature Control Stage for Deposition of Thin Metal Films(Houghton University, 2023-04-15) Fall, Owen; Yelle, Luke; Hoffman, BrandonBecause the properties of the films are significantly affected by a deposition temperature change of only several degrees Celsius, it is vital that the substrate temperature be uniform across the entire substrate and constant throughout the deposition process, even while it is being radiatively heated by the evaporant metal. A temperature control substrate stage is being developed at Houghton University for thin metal films produced on 10 cm Si substrates via physical vapor deposition, with a base pressure of 10-6 Torr. To test possible substrate-stage adhesion materials, a test chamber was set up containing a substrate fixed to a 10 cm diameter aluminum heat sink. Resistive wire was epoxied to the substrate surface to simulate the ~6.5 W of radiative heating that would occur during deposition. Using double-sided copper tape, the minimum temperature change was 18°C in 10 minutes. Adding clamps decreased this to 13°C in 10 minutes. Using Ag paste as an adhesive resulted in a temperature change of only 3°C in 10 minutes.XLI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY), April 15, 2023.
- ItemSimulating Decay Energy Spectra Using Geant4(Houghton University, 2023-04-15) Ockri, Timothy R.; Koehler, Katrina E.; Fitzgerald, Ryan P.Decay Energy Spectroscopy (DES) uses high energy resolution (~1 keV FWHM at 5 MeV ) microcalorimeters to measure the total energy of each decay from an embedded radioactive source. A histogram of these energies enables the determination of radionuclide composition, useful for both nuclear safeguards and metrology. In some fraction of decays, some of the decay energy is not thermalized when a particle such as a gamma ray, X-ray, or electron escapes the detector. The probability of this happening depends on the location of the parent nucleus in the absorber, the types and energies of particles released in the decay, and the material,size, and shape of the absorber. A library of possible spectra is created by simulating different shapes and sizes of detector absorbers and compositions, locations, and distributions of sources using the Monte-Carlo particle simulation software Geant4. With Decay Energy Spectroscopy SIMulation for Absolute Total Efficiency (DESSIMATE), a python graphical user interface for visualization, an experimental spectrum can be expressed as a linear combination of these simulated spectra. This will allow the total activity of each radionuclide in a measured sample to be determined. This method can potentially be used in the certification of Standard Reference Materials (SRMs) with precisely known massic activities (defined as unit activity per unit mass).XLI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY), April 15, 2023.
- ItemAn Experiment Simulating the Production, Capture, and Detection of 8Li from an ICF Implosion(Houghton University, 2023-04-15) Lei, Chunsun; Hotchkiss, Andrew; Brown, Adam E.; Martin, Andrew L.; Yuly, Mark; McLean, James G.; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, Sean P.Inertial confinement fusion (ICF) is a possible tool for measuring light-ion nuclear cross sections. One way to do this might be to trap and detect the radioactive decays of the product nuclei produced using a doped target capsule. Some of the highest yield light-ion reactions that could be studied using this technique are 6Li(t,p) 8Li and 9Be(t,α) 8Li, both of which produce 8Li . In order to simulate this method, a natural lithium film was deposited onto a tungsten substrate, which was then activated via the 7Li(d,p) 8Li reaction using the SUNY Geneseo Pelletron accelerator. A current pulse of up to 1000 A was discharged through the tungsten raising its temperature to as high as about 1500 °C in less than a few milliseconds, causing the lithium to rapidly evaporate and produce a gas of neutral lithium atoms which then travelled outward and stuck to the aluminum getter detector foil of the Short-Lived Isotope Counting System (SLICS). This phoswich detector was used to identify beta particles and count in situ the 840 ms beta decay curve for 8Li as a function of time in order to estimate the efficiency of SLICS for trapping and detecting ICF reaction products. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton University.XLI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY), April 15, 2023.
- ItemDepositing Lithium Films to Simulate ICF Reaction Products(Houghton University, 2023-04-15) Lei, Chunsun; Hotchkiss, Andrew; Martin, Andrew; Brown, Adam; Yuly, Mark; Mclean, James G.; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, Sean P.A possible future experiment using Inertial Confinement Fusion (ICF) to measure low energy light ion nuclear cross sections has been simulated using the SUNY Geneseo Pelletron to activate a thin lithium target which was then rapidly evaporated, trapped, and detected. This experiment required a lithium film to be deposited in a vacuum of approximately 10 5 Torr onto the surface of a thin tungsten foil. The films were produced by heating natural lithium pellets to 400 C in a stainless steel boat through which 20 A of current was passed. The evaporated lithium was contained inside a stainless steel “house” inside the vacuum chamber, with a small opening on the top that allowed the lithium to reach the tungsten foil. The vacuum chamber was in an argon filled glove bag which allowed the films to be briefly removed and handled since lithium reacts vigorously with oxygen and water vapor. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton University.
- ItemAn Experiment to Simulate Trapping and Detection of Radioactive Isotopes Produced in ICF Implosions(Houghton College, 2022-04-27) Christensen, Micah J.; Condie, Micah K.; Brown, Adam E.; Yuly, Mark; McLean, James G.; Padalino, Stephen J.; Forrest, Chad J.; Sangster, Thomas C.; Regan, SeanIt may be possible to measure the low energy nuclear cross sections of light ion reactions by trapping the reaction products from an Inertial Confinement Fusion (ICF) implosion and detecting their beta decays. To test this idea, an “exploding wire” experiment was 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 65 Cu(d, p) 66 Cu. A current pulse through the tungsten 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 66 Cu beta decays using two trap designs, one using a getter and the other a turbopump. Both designs used the Short Lived Isotope Counting System (SLICS), consisting of plastic scintillator phoswich detectors and fast electronics, to identify and count the beta particles. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics, and by SUNY Geneseo and Houghton College.OMEGA Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 27, 2022; 63rd Annual Meeting of the APS Division of Plasma Physics, Pittsburgh, PA, November 8-12, 2021; XL Annual Rochester Symposium for Physics Students, University of Rochester, April 8, 2022; 2022 Omega Laser Facility Users Group Workshop Student Poster Award