2018 APS Conference for Undergraduate Women in Physics (CUWiP)

Poster Abstracts

Experimental Realization of the Hannay Hoop & Bead Anholonomy
Norah Ali, Hwan Bae, John F. Lindner
Hiram College
Certain systems do not completely return to themselves when a subsystem moves through a closed circuit in physical or parameter space. A geometric phase, known classically as Hannay’s angle and quantum mechanically as Berry’s phase, quantifies such anholonomy. We study the classical example of a bead sliding frictionlessly on a slowly rotating hoop. We elucidate how forces in the inertial frame and pseudo-forces in the rotating frame shift the bead. We then generalize the effect to arbitrary — not necessarily adiabatic — motions. We thereby realize the dynamics with a simple apparatus of wet ice cylinders sliding on a polished metal plate in 3D printed plastic channels.

Quasar Outflows and Physical Parameters
Dr. Rajib Ganguly, Daniel Agar, Gavin Trevorrow, Paul Manion, Alexandria Bakhsh, Et. al.
University of Michigan-Flint
Quasars outflows: their geometry, their physical conditions, their velocities, how these are related to physical parameters (e.g., black hole mass, accretion rate), and how outflows affect the galaxy hosting the quasar.

Microwave spectroscopy of ultracold molecular plasma
Fernanda B. V. Martins, James S. Keller, Edward R. Grant
Kenyon College
One exciting route to the formation of ultracold plasma is through a cold, dense cloud of highly excited Rydberg molecules — states for which a loosely bound electron interacts substantially with its neighboring molecules. In a custom-built vacuum chamber, a molecular beam composed of nitric oxide in a rare gas carrier is directed past a laser-interaction region to a distant micro-channel plate detector that is sensitive to charged particles. Nitric oxide molecules undergo a two-photon, resonant excitation to yield a high density of Rydberg states, which evolve into stable ultracold plasma. In this project, microwave radiation is used as a direct and selective tool to study Rydberg populations and ultracold plasma. Resonant microwave fields allow the signal corresponding to different quantum numbers to be selectively enhanced in both the pulsed-field ionization (PFI) and the action spectrum of plasma. We demonstrate that two frequencies are resonant to each optically bright Rydberg state, and that they correspond to the energy spacing between adjacent quantum numbers, n. Microwave fields appear to substantially enhance the lifetime of excited molecules that exhibit rapid dissociation in field-free conditions. Finally, the results are compared to the microwave field effect in the presence of small dc electric fields, which, depending on the magnitude, either intensify or dramatically diminish the observed enhancements.

Maitland Bowen, Jeffrey McMahon, Sara Simon, Grace Chesmore
University of Michigan - Ann Arbor
The cosmic microwave background is the afterglow of the universe’s most extreme high-energy physics event fourteen billion years ago. Exploring the CMB allows for a new level of understanding of the fundamental nature of space by tracing growth of large-scale structure. Direct experimentation and observation of the CMB yields advanced insight into primordial quantum perturbations, inflation, neutrino mass scale, new light particles, dark matter, dark energy, and maps of all cumulative mass in the universe.

The upcoming CMB Stage IV experiment, CMB-S4, will be the definitive ground-based project of its kind. Its proposed scientific goals would improve known constraints on inflation and dark matter by as much as an order of magnitude from current Stage III CMB telescopes. However, achieving this will require an understanding of the details of potential telescope designs at an unprecedented level. Multiple CMB-S4 telescope candidates are currently being developed, including a 6.7-meter telescope to be constructed at Simons Observatory (SO). Using current schematics from SO and CCAT-prime, our research involves designing a 1/10th scale functioning model of the upcoming SO telescope to gain a better understanding of its innovative crossed-Dragone design. This experiment, known as CMB-S4/10s, will allow for the characterization of all systematics before the final telescope design is complete.

Detector Development for the Deep Underground Neutrino Experiment
Ibrahim Chahrour
Wayne State University
Neutrinos (νe, νμ, ντ) can change from one flavor to another through a quantum mechanical process called “neutrino oscillation”.  The Deep Underground Neutrino Experiment (DUNE) will send neutrinos 1300 km from Fermilab to Sanford Underground Research Facility (SURF) to study this phenomenon. We are investigating a heavy water detector that can help constrain difficult uncertainties  in the interaction of neutrinos. Understanding neutrino oscillations might be the key to understanding the matter-antimatter asymmetry in the universe.

Development of New Barrel Array Design for Transfer Reactions with Fast Beams
F.Corrado, D. Walter, S.D Pain, J.A Cizewski
Allegheny College
Single-nucleon transfer reactions allow for extraction of spectroscopic information on unstable and exotic nuclei, providing details for understanding the rapid neutron capture process (r-process). To study exotic, neutron-rich isotopes, inverse kinematics is needed with light targets and beams of heavy projectiles. Measurement of the 84Se(d,p)85Se reaction at 45MeV/u will be conducted at the NSCL in December 2017 to extract spectroscopic information on the 85Se nucleus. Single-particle transfer reactions in inverse kinematics at high energy – such as that for the 84Se(d,p) – are uncommon and require new designs and techniques to be developed. A modification to the current ORRUBA barrel design is needed to accommodate such changes. Features of this design include: a modular barrel able to cover a large desired angular range and detector coverage at backward angles in the lab, as well as allow for easy access to detectors without affecting the rest of the configuration. Improvements to the current design will be presented, including discussion of use in future transfer reactions with fast beams.

DAQ and Background Analysis for the KOTO Experiment
Kristin Dona and Molly Taylor
University of Michigan
The KOTO experiment is a high-energy particle physics experiment located at the J-PARC research facility in Tokai, Japan. The immediate goal of the experiment is to measure the branching ratio for the neutral kaon decaying into a neutral pion and two neutrinos. This decay is extremely rare: the branching ratio predicted by the Standard Model is less than 1 per 30 billion. Due to the rarity of this decay, it has yet to be experimentally observed; however, measuring its branching ratio is one of the best opportunities for observing additional contributions to CP violation. CP violation is related to the matter-antimatter asymmetry in the universe, but current Standard Model predictions are not sufficient to explain the observed disparity. An experimental branching ratio measurement will either confirm Standard Model predictions or point towards new physics. Since the decay we are looking for is very rare, we need to be able to distinguish our decay from all other events coming into the detectors. Thus, we need both a specialized data acquisition (DAQ) system and a complete understanding of the background inside the KOTO detectors. Being able to recognize other decay modes that mimic the signal is necessary for measuring the rare decay rate. This poster will present an overview of the DAQ system structure and outline a background analysis for collected data. This analysis will look at the regeneration of long lived neutral kaons into short lived neutral kaons as they pass through the detector, and determine the amount that regeneration contributes to the background.

Charge Management in LISA Pathfinder: The Continuous Discharging Experiment
Becca E. Ewing
Wright State University
Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

Magnetism in Titanium-Doped Vanadium Dioxide
Mariah R. Goeks, P. W. Mengyan, and R. L. Lichti
Northern Michigan University
Here we present a characterization of the recently discovered magnetic phase in titanium-doped vanadium dioxide (VO2:Ti with 1, 3 & 5 at%) via Muon Spin Relaxation (MuSR) measurements. Specifically, variations in the magnetic phase were studied as a function of titanium dopant concentration in an effort to understand the fundamental mechanism responsible for magnetism and other transitions exhibited by the material.

Muons are spin 1/2 particles with an average lifetime of 2.2 us and a gyromagnetic ratio of 135.54 MHz/T that are used to study the local magnetic environment through a technique known as Muon Spin Relaxation/Rotation/Resonance (MuSR). Implanted muons precess about the field in their local environment until they decay into a positron that is preferentially aligned with the spin direction at the time of decay (and associated neutrinos). By tracking these positrons, the time evolution of the muon spin polarization is determined and used to map the local magnetic field distribution at the muon stopping site.

VO2 exhibits an ultra-fast, reversible metal−semiconductor transition (MST) at TMST near 340 K. Above TMST it is metallic, reflective and electrically conductive; below, the electrical conductivity drops by several orders of magnitude, it is transparent with a bandgap of 0.7 eV. The MST can be triggered by thermal, optical, electrical or barometric means and is accompanied by a structural transition. Dopants like tungsten and Ti reduce TMST to below room temperature while having minimal effect on the electronic or optical properties of the host, whereas dopants such as fluorine and chromium can raise it to above 400 K. While VO2 has been studied since the 1960s, its low-temperature magnetic phase was first reported in 2014 by our collaboration. This contribution is part of a large-scale project aimed at understanding the fundamental mechanism responsible for transitions in VO2 compounds, a question still highly debated within the community.

Successful Women in Physics and the Experiences that Inspired them
Jordan Gregor, Halie Lewis
Edinboro Univ of PA
In the field of physics, the lack of diversity is a well-known and documented problem, in particular the low number of women.  Many studies have attempted to identify reasons women choose not to enter into or persist in the field of physics.  This research project instead focused on identifying factors contributing to the success of women in physics.

The data collected for this project included a preliminary survey, responses from an interview conducted either in person or by video conference, and a final survey focused on mindset characteristics.  In total, 51 women participated in the study.  All participants held at least a bachelor’s degree in physics.  Most of the participants were pursuing higher degrees while others were in the workforce in either academia or industry.

Preliminary analysis has identified three key factors in what the women attributed their success to and how they overcame struggles despite the differences in their backgrounds.  These three factors were mentorship, a strong support system, and having research opportunities.   In addition to these factors, the mindset scores for all participants favored a growth oriented mindset.  The results of this study may be used to increase the effectiveness of “Women in Physics” initiatives and increase the number of women in physics.

Using Alternative Semiconductors for Alternative Energy
Gillian Hagen, Benjamin Zank, Annie Choi, Emma Grotto, Meg Hwang, Michelle Wellman
Mount Holyoke College
The purpose of this research is contribute to fundamental science on the physics of solar cells, leading to the development of efficient and thin, multi-layer flexible solar cells. This project focused on developing fabrication procedures for PbS Quantum Dot solar cell devices and testing device performance. The fabrication of PbS (Lead-Sulfide) Quantum Dot solar cells incorporates spin coating, ligand-exchange, annealing, and thermal evaporator film deposition. Our aim was to achieve an open circuit voltage of approximately 0.6V. Using quantum dots of approximately 1.0eV, we worked to optimize layer thickness and material energy levels to efficiently transport holes and electrons and maximize short circuit current density to reach a current of 10mA to 15mA. We aimed to achieve high values for open circuit voltage, short circuit current density, and fill factor. Through focusing on the optimization of quantum dot surface chemistry and charge carrier transport rather than absorption mechanisms, we expected to achieve Efficiency values of at least 1.00%. Our best device had an open circuit voltage of approximately 0.502V and an Efficiency of 2.89%. Analysis of fabricated devices incorporated spectrophotometry to measure device absorption and I-V characteristic testing to analyze device current and voltage. This project will provide insight into effective solar cell device structures and fabrication procedures that will inform future research on tandem solar cells.

Detection and Characterization of Micrometeoroid Impacts on LISA Pathfinder
S. Hourihane, T. Littenberg, J. Baker, N. Pagane, J. Slutsky, J. Thorpe
University of Michigan
LISA Pathfinder (LPF) was a joint ESA/NASA technology demonstration mission for the Laser Interferometer Space Antenna (LISA) gravitational wave observatory. LPF, the most sensitive accelerometer ever flown in space, was launched in December 2015 and successfully concluded its mission in July 2017. Due in part to LPFs success, LISA was selected by the European Space Agency for launch in the early 2030s. An ancillary benefit of LPFs capabilities made it a sensitive detector of micrometeoroid impacts. We report on the capabilities of LPF to detect and characterize impacts, and progress towards using those inferences to advance our understanding of the micrometeoroid environment in the solar system. In doing so, we assess the prospect of space-based gravitational wave observatories as micrometeoroid detection instruments.

Studying the Volume Phase Transition of Polymeric Microgels
Samantha Hudson, Hiram College, Samantha Tietjen, Kiril A. Streletzky
Hiram College
This project specifically investigated the volume phase transition of polysaccharide microgels synthesized with addition of a cross linker in a surfactant solution.  The addition of surfactant raises the Lowest Critical Solution Temperature (LCST) of the polymer. Maintaining this temperature for the duration of a 3 hour bath is crucial for microgel synthesis.  Three separate baths were used to achieve these stable synthesis conditions. While the majority of Microgels were synthesized in a singular, stable bath, microgels synthesized in a less stable temperature system were found to have larger hydrodynamic radii (Rh).  The synthesis process was varied systematically by changing the amount of used cross-linker and surfactant. The resulting microgels were characterized using Dynamic Light Scattering (DLS) across multiple angles and at temperatures varying from 20 to 60ᵒC.  Flory-Huggins mean Field theory was then used to describe microgel’s deswelling with increase of temperature. The theoretical model was fit to the experimental DLS data (Rh vs. T).  Fit results, including enthalpy, entropy, number of polymer chains per microgel, and a material constant, suggest a dependence of polymer chain interactions during synthesis on the amount of cross-linker. Further development of the Flory-Huggins model is needed to directly account for effect of cross-linker and surfactant on synthesized microgels.

Thanks to the NSF (Grant #1659541) for funding this research.

Making Microlensing Predictions with a Population Synthesis Milky Way Model
Macy J. Huston
Ohio State Univ - Columbus
Recent microlensing surveys have provided the astronomy community with estimates of microlensing optical depth and timescale distributions. These properties depend on stellar distributions, masses, and kinematics, so we can use them to constrain Galactic models. Inversely, we use Galactic modelling to make predictions for future large-scale microlensing surveys, like UKIRT and WFIRST. I’ve been working for a few semesters on developing a more flexible Milky Way model, with output well-suited for microlensing calculations. After some recent modifications, including a slightly less massive two-component Galactic bulge and a more sensible kinematic model, updated microlensing observable maps are being generated. My poster will present the model in its current form, as well as a comparison of these new maps to previous model versions and real data from the MOA-II survey. 

Reconstruction of T` Mass in Search for Dark Matter Particle Candidates in the CMS Experiment
Alex Jackson, Helmut Vogel
Carnegie Mellon Univ
Investigating the T’ heavy top-like quark decay to reconstruct accurate invariant mass, aiding in the search of dark matter particle candidates. When neutrino are produced in decays within a detector such as the Compact Muon Solenoid (CMS) experiment at the LHC at CERN, it is nearly impossible to detect them. By analyzing well know distinctive decay channels is it possible to reconstruct information about undetected neutrinos produced in the decay. This is because neutrinos interact only weakly, which results in them being able to pass through normal matter without leaving a trace, making detection using conventional methods impossible. Applying a method of reconstructing invariant mass to the decay of the T’ quark, T’ -> bW, where W-> lv, which has a neutrino among its decay products, we can reconstruct the neutrino momentum. This can then be used to determine the mass of the T’ particle to a greater level of accuracy. Which then allows us to look at rarer decays of the T’, for example T’ -> tX, where X is a n undetected dark matter particle candidate.

Exploring Gendered Performance Differences in Introductory Physics
Nita Kedharnath
University of Michigan
Gendered performance differences (GPDs) in physics are an unfortunate reality at many universities throughout the country. Despite entering these classes with the same cumulative GPA, ACT math scores, and other relevant academic factors, often times women perform worse than men, particularly on exams. In fact, on average, women perform one-third of a letter grade lower than men in introductory physics. After examining various class factors, we conclude that stereotype threat, the fear of confirming a negative stereotype about one’s identity when in an evaluative environment, is a likely cause for these GPDs since the extra anxiety often leads to underperformance.

Electron Transport in Bi1-xSbx Nanowires Grown Using Molecular Beam Epitaxy
Nicolette Kier
University of Pittsburgh
Topological insulators are a recently discovered quantum state of matter characterized by insulation in the bulk of the material and conduction on its surface. They exhibit the property of polarized spin current on the surface, which will preserve electron coherence and thus are a viable material for the use of spintronics. Nanomaterials are a preferred material to study these surface effects as they have a much larger surface to volume ratio and can be used in the fabrication of nanodevices. The use of TI nanowires as the active conduction channel of devices also allows for superior current-voltage characteristics as opposed to semiconductor nanowire transistors. Bi1-xSbx nanowires were one of the first known topological insulators and show great promise as electronic devices, and thus have been studied intensively. Bi1-xSbx wires have previously been synthesized through solvothermal methods, laser vaporization, electron beam writing and many other techniques. However, these methods do not result in the purity levels preferred for electron transport. In this study, Bi1-xSbx wires were grown via molecular beam epitaxy, resulting in wires with little to no crystalline defects. They were then used as the conduction channel in high performance field effect transistors. Field effect mobility and magnetoresistances, which play an important role in electron current, were then studied.

Searching for Brown Dwarfs in the Orion Molecular Clouds
Heidi Kuchta
The University of Toledo
 I am looking for brown dwarfs in the less populated regions of the Orion Molecular Cloud to provide further information about brown dwarfs and their formation regions. This is being done using data taken in the visible and infrared bands. Now that I have identified brown dwarf candidates they will be confirmed using a spectograph on the Discovery Channel Telescope.

A Novel Technique of Fluorine Detection in Soil by means of PIGE Analysis
Brieana Linton, Dr. Paul A. DeYoung
Hope College
Brieana K. Linton A class of chemical compounds known as per- and polyfluoroalkyl substances (PFASs) are found present in many consumer products and are being used in fire-fighting foams during daily safety drills at airports. These fluorochemicals migrate from fire-fighting foams and consumer products in landfills contaminating the surrounding soil and ground water. In addition to the PFASs environmental persistence, they also exhibit immunotoxicity within the human body. Ion beam analysis by means of Particle Induced Gamma-ray Emission (PIGE) spectroscopy provides a quantitative measurement of the total fluorine concentration in various samples. In order to develop a protocol for fluorine-detection in contaminated soil, standards of fluorinated soils were prepared in pellet form with varying known concentrations of Perfluorooctanoic Acid, a specific PFAS, along with varying mixtures of sand and organic topsoil. A method of separating PFAS from naturally occurring fluorine in soil is being developed in order to quantitatively measure fluorine contamination. Chemical washes are collected in Weak Anion-exchange (WAX) cartridges to determine the concentration of fluorine that has been removed successfully. Soil measured with PIGE analysis after a chemical wash yields a lower concentration of fluorine compared to the pre-washed contaminated soil.
This work was generously funded by the National Science Foundation under NSF Grant No. RUI: PHY-1613188 and PHY-1306074.

Hydrothermal Synthesis of Y2O3 Powder
Juan Lopez, Dechao Yu, Daniel Kopp, and Richard Riman
The University of Toledo
In the combustion environments of gas turbines, Al2O3/Al2O3 ceramic matrix composites (CMCs) are widely used to increase performance, including efficiency and durability. However, the high temperatures of these applications promote grain growth, sintering, and deformation. Due to the degradation of the Al2O3/Al2O3 CMCs in these environments, damage tolerance is reduced. Along with this, Al2O3/Al2O3 CMCs experience further degradation due to the formation of aluminum hydroxide when disposed to rapid flowing, water-vapor rich combustion gasses. Therefore, environmental stability for said materials is an issue which must be addressed. Y2O3, yttria, is recognized as a chemically and thermodynamically stable material, and the thermal expansions of α-Y2O3 and Al2O3, alumina, are extremely similar. Hence, in this study, the crystallization of yttria via hydrothermal synthesis was explored as the properties of yttria suggest a promising coating candidate for Al2O3/Al2O3 CMCs. Using yttrium chloride and yttrium nitrate precursors, many reactions were completed through the hydrothermal and solvothermal method in attempt to produce and collect yttria without post-treatment. The results suggest that higher temperatures and hold times than those experimented with in this study are required for the formation of yttria. However, there exist other pathways via hydrothermal and solvothermal synthesis that could potentially crystallize yttria. In conclusion, these results illuminate a path to the creation of yttrium oxide coatings for aluminum oxide substrates. Reference: Mechnich, Peter, and Wolfgang Braue. "Air Plasma-sprayed Y2O3 Coatings for Al2O3/Al2O3 Ceramic Matrix Composites." Journal of the European Ceramic Society 33.13-14 (2013): 2645-653.

On the Hall Effect Measurements
Gina M Lucia, Arthur H Siwecki, Mohamed Ahoujja, Said Elhamri
University of Dayton
The Hall Effect has long been the standard experimental technique to measure the free carrier concentration, mobility and resistivity in semiconductor materials. In this presentation, we will describe in details the functions of all the equipment of our Hall Effect setup in our laboratory on campus. Because the Hall system is fully automated and controlled by a computer, the emphasis will be focused on explaining how the measurements are made and how the calculated carrier concentration, mobility and resistivity are obtained as a function of temperature from these measurements.

Using a Staggered Herringbone Microfluidic Mixer to Synthesize Gold Nanoparticles
Jacqueline Matz, Brian Hama, Chandra Kothapalli
Duquesne University
Microfluidic mixers provide efficient mixing using smaller volumes of reactants than traditional batch reactions. They have additional advantages such as low-cost, control of variables, ease of in situ imaging, and efficient heat transfer. Among them, active micromixers require an external power source while passive micromixers do not require external energy [1].  We recently designed a passive micromixer by patterning microfluidic channels with staggered herringbone ridges; this design relies on chaotic advection and low Reynolds numbers (Re<100) to achieve efficient mixing [2]. Simulations using this pattern resulted in a mixing index close to one, within 6 mm length of channel. For further implementation, in this study we aim to produce gold nanoparticles using the micromixer based on the staggered herringbone design. Gold nanoparticles were synthesized by pumping separate solutions of sodium citrate dihydrate and gold chloride trihydrate, at different concentrations, through the micromixer and collecting the resultant solutions. Separately, batch reactions were carried out at the same concentrations to compare outcomes from micromixing. Resulting solutions were characterized using scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis), and dynamic light scattering (DLS). [1] Nguyen, N. and Wu, Z.; Journal of Micromechanics and Microengineering, 2005, 15, R1-R15. [2] Hama, B.; Evaluation of a microfluidic mixer utilizing staggered herringbone channels: A computational fluid dynamics approach. Thesis accepted for fulfillment of Master’s degree in Chemical Engineering, Cleveland State University, 2017.

Nanomechanical Probes of Sketched LaAlO_3/SrTiO_3 Single-Electron Transistors
Jessica Montone
University of Pittsburgh
Nanoscale devices that manipulate single electrons present an exciting platform for the observation of electronic and mechanical effects. By utilizing the locally tunable metal-insulator transition at the interface of LaAlO_3/SrTiO_3, we can create single-electron transistors using conducting atomic force microscope (c-AFM) lithography. The piezoelectric nature of LaAlO_3/SrTiO_3 gives way to an expected coupling between mechanical motion and electric charge within the device. We can test this effect by applying pressure to the device using an insulating AFM tip while measuring changes in electron density. A cryogenic AFM system is used to examine this effect, as many of the most interesting properties of single-electron transistors are only observed at low temperatures.

Ray Propagation Modeling in the Detection of Ultra-High Energy Neutrinos
Spoorthi Nagasamudram with Prof. Connolly, Dr. Pfender, Prof. Hanson
Ohio State Univ - Columbus
The detection of ultra-high energy (UHE) neutrinos can probe into Physics at the highest energies (greater than 1018 eV). The Askaryan effect makes it possible to detect UHE neutrinos. The interaction of a UHE neutrino with a dielectric medium produces a shower of particles that travel faster than light in the medium. The resulting electromagnetic radiation is coherent at radio wavelengths. This is called the Askaryan effect. The South Pole is a promising site to detect UHE neutrinos because there is a lot of ice. Also, the radio attenuation length of the ice is about 1 km, preventing significant energy loss. The goal of my project is to model the propagation of rays within the ice and use this model to find optimal rays that hit the detector. The index of refraction, n(z), of ice changes with its depth, causing rays to bend. We traced the path of the ray in very small steps (on the order of 10-4 m). After doing so, we scanned a range of rays with different initial angles. For each ray, we calculated the vertical distance by which the ray missed the detector. A function of initial angle that predicts the vertical miss distance can then be deduced. The optimal rays are the roots of this function. The results we found using this procedure were encouraging. We found ray solutions with miss distances on the order of a few centimeters which is reasonable. In the future, we would like to use this code in the simulation to analyze the amount of power reaching the detector. This might help understand the effect of different n(z) models on the expected number of neutrinos. We also want to understand how this technique of ray solving performs in terms of speed.

Laser Ablation Source Operation and Characterization of Ion Sources
Jessica Peck, Dr. Matthew Redshaw, Nadeesha Gamage, Madhawa Vidurinda
Central Michigan University
At CMU we are developing a Penning trap for ultra-high-precision mass measurements using single ions. A novel double-Penning trap will be built for simultaneous mass comparisons between two ion species. The Penning trap will be housed inside a 12 tesla superconducting magnet and will be used for measurements with stable and long-lived isotopes produced from a variety of ion sources including an electron impact ionization source and a laser ablation source. The use of externally produced ions allows access to a wide range of elements and isotopes. The research program will include precise atomic mass measurements for atomic and nuclear physics, Q-value measurements for neutrinoless double-beta-decay and double-electron capture candidates, neutron separation energy measurements for a test of E=mc2, and dipole moment measurements of polar molecular ions.

Comparison of Charge Storage Properties of Prussian Blue Analogues Containing Copper and Cobalt
Else Amanda Rensmo
Hope College
Prussian blue analogues (PBAs) are interesting materials of study because of their charge storing capacity. These materials can have a potential for battery technology applications if the effects of their composition and structure are understood. The focus of this study was to analyze the effects of the addition of copper or cobalt to a nickel deposition solution on the resulting PBA films. Solutions with constant metal concentration, but with different relative concentrations of NiCu and NiCo, were electrodeposited on a gold substrate through controlled potential electrolysis. In a hexacyanoferrate solution, the sample was modified in a cyclic voltammetry (CV) experiment to produce the PBA. The capacity of the modified film was characterized with CV scans using different scan rates. In addition, a scanning electron microscope with energy dispersive x-ray spectroscopy was utilized for examining the structure and composition of the film before and after the modification step. Preliminary results show that depositing the desired amount of copper was difficult whereas the cobalt depositions were more easily controlled. Yet, the deposition of copper resulted in more stored charge than that with cobalt. The amount of copper or cobalt has no effect on the kinetics or the potential of the reaction. This work was generously funded by the National Science Foundation under NSF-RUI Grant No. DMR-1608327 and NSF-MRI Grant No. CHE-0959282.

Brachytherapy optimization using radiobiological-based planning for high dose rate and permanent implants for prostate cancer treatment
Kaelyn Seeley, J. Adam Cunha, Tae Min Hong
University of Pittsburgh
We discuss an improvement in brachytherapy—a prostate cancer treatment method that directly places radioactive seeds inside target cancerous regions—by optimizing the current standard for delivering dose. Currently, the seeds’ spatiotemporal placement is determined by optimizing the dose based on a set of physical, user-defined constraints. One particular approach is the “inverse planning” algorithms that allow for tightly fit isodose lines around the target volumes in order to reduce dose to the patient’s organs at risk. However, these dose distributions are typically computed assuming the same biological response to radiation for different types of tissues. In our work, we consider radiobiological parameters to account for the differences in the individual sensitivities and responses to radiation for tissues surrounding the target. Among the benefits are a more accurate toxicity rate and more coverage to target regions for planning high-dose-rate treatments as well as permanent implants

Let Me Give You A Hand
Ekaterina Shick
Alma College
I started working on this project this semester in fall 2017. I originally became involved because I hand hand surgery myself and was interested in how the hand prosthetic`s work. Also, I`m from a second world country so super into giving them things and opportunities they never had. This project means so much to me. This project works on making a hand prosthetic through recycled parts that way its easier for people from all across the world to access. It will come in a kit easy to adjust and fix. I think everyone should hear about it and also get an opportunity to see how it works. 

Hall Effect Studies of LPCVD grown β-Ga2O3 on Sapphire
Danielle E. Smith, Said Elhamri, Adam T. Neal, Hongping Zhao, Shin Mou
University of Dayton
With its ultra-wide bandgap of 4.5-4.9 eV and large breakdown electronic field, β-Ga2O3 has recently attracted attention because of its potential for next generation power electronics applications.  The estimated breakdown field for β-Ga2O3 is 8 MV/cm, much larger than 2.5 MV/cm for 4H-SiC and 3.3 MV/cm for GaN, which could enable power electronics with larger power density and greater efficiency [1].  Also, Ga2O3 has the potential to be more cost-efficient in mass production than other wide bandgap materials due to its ability to be synthesized through standard melt growth methods [2].  With this motivation, this study examines the electronic properties of β-Ga2O3 via temperature dependent Hall effect measurements.  The Ga2O3 was grown on c-face sapphire substrates via low pressure chemical vapor deposition (LPCVD) using liquid metal gallium and oxygen precursors, with silicon dopants introduced via SiC4 gas. [3] Hall effect measurements were performed to determine carrier density and mobility as a function of temperature.  The sign of the Hall voltage indicates that the Ga2O3 is an n-type material with electrons as majority carriers.  The temperature dependence of the carrier density indicates activation energies of 10.7 meV and 10.1 meV for the Si dopant using samples with room temperature electron densities of 2×1018 cm-3 and 3×1018  cm-3, respectively. Among several samples, the highest measured mobility was 34 cm2/Vs at room temperature and 40 cm2/Vs at 150K. These results indicate the potential of LPCVD grown Si-doped Ga2O3 for next generation semiconductor power electronics applications.
[1] Applied Physics Letters 100, 013504 (2012)
[2] Applied Physics Letters 103, 123511 (2013)
[3] Applied Physics Letters 109, 132103 (2016)

Phase transitions and associated phenomena in Ni 2+x Cr 0.15 Mn y Ga Huesler alloys
Heather Statt, Mahmud Khan
Miami University
Heusler alloys exhibit many exciting properties that are important from both fundamental and application viewpoints. Ni 2 MnGa and its derivative materials are one of the most extensively studied Heusler alloys. The exciting properties of these materials are related to the first order martensitic phase transformation that they exhibit. In the vicinity of this transformation interesting anomalies are observed in the magnetic and transport data of the materials. Here, we present an experimental study on a series of Ni-Cr- Mn-Ga based Heusler alloys explored by x-ray diffraction, magnetization, electrical resistivity, and SEM measurements. Six Ni 2+x Cr 0.15 Mn y Ga (0.05 x 0.2; 0.65 y 0.80) samples were fabricated holding Cr and Ga ratios constant while varying the Ni and Mn ratios. All samples exhibited the first order martensitic phase transformations when cooled from 400 K to lower temperatures. Additionally, ferromagnetic transitions were also observed in all compounds. For some compounds the martensitic and ferromagnetic transitions are decoupled, while in the compounds with Mn concentration y > 0.7, ferromagnetic and martensitic phase transitions are coupled, i.e., they occur at the same temperature. Furthermore, intermartensitic phase transformations were observed in selected samples with y < 0.75. For all samples, a sharp drop in resistivity has been identified near the proximity of the martensitic phase transformation. All results will be discussed in detail.

Characterization and Synthesis Optimization of Polymeric Microgels
Samantha Tietjen, Samantha Hudson, Kiril A. Streletzky
Cleveland State University
Microgels are spherical particles suspended in solution, comprised of crosslinked polymer chains. Due to the amphiphilic property of the parent polymer, microgels display a temperature dependent de-swelling property, and therefore have the potential to be used for drug delivery. In this case, microgels were synthesized using hydroxypropyl cellulose (HPC) polymer and divinyl sulfone (DVS) cross-linker, as well as dodecyltrimethylammonium bromide (DTAB) surfactant to decrease particle size and promote microgel monodispersity. Synthesized particles were then characterized using dynamic light scattering (DLS) for both temperature and angle dependence to determine hydrodynamic radius, Rh, at a range of temperatures showing a transition from the swollen to de-swollen states. Previous studies suggest that increasing the concentrations of either the chemical cross-linker [1] or the surfactant [2] reduce Rh. Primary experiments focused on the variation of DVS and DTAB concentrations. Increasing the DVS:HPC ratio from 1 to 30 results in microgels that decrease in swollen size from 190 to 150nm and de-swollen size from 95 to 65 nm. However, at higher DVS:HPC ratio synthesized particles grow rather than shrink with increasing temperature. Surprisingly, increasing the surfactant concentration resulted in an increase in Rh; this might be related to DTAB effect on polymer transition temperature. Additionally, DLS experiments revealed a dependence of Rh on microgel concentration in samples. Rh at infinite dilution was extrapolated from the concentration dependence. Continued work with the synthesis procedure also revealed the importance of a meticulous synthesis procedure; most notably in regards to polymer stock preparation, pH and temperature control, and consistent stirring.

Light Scattering Study of the Size and Shape of Mixed Elastin-Like Polypeptide Micelles
Ilona Tsuper, Daniel Terrano, Bryce Noe, Richard Schmidt, Kiril A. Streletzky, Nolan B. Holland
Cleveland State Univeristy
Elastin-Like Polypeptides (ELP) formed thermoreversible nanoparticles by having three-armed star polypeptides (each with 20 repeats of (GVGVP) amino acid sequence) extending from the negatively charged foldon domain. In addition, linear constructs composed of 40 repeats of the (GVGVP) sequence were introduced into the system. The mixed ELP polymer system is soluble at room temperature and becomes insoluble at ~ 50℃ forming micelles with the foldons on the exterior and linear constructs at the core. Above the transition, the size and shape of the mixed micelles are dependent on the pH of the solution, concentration of the PBS, and the ratio of the linear to foldon concentration. The Depolarized Dynamic Light Scattering was employed to study the structure and dynamics of the mixed micelles at 62 oC and pH of 7.3 - 7.5. The ELP foldon micelles have a radius of 10 nm; the introduction of the linear ELP chains leads to a growth of mixed micelles at a linear rate, at fixed PBS and foldon concentrations. A developed molar volumes model explains the linear size growth of the mixed system. Static Light Scattering results largely support the model. However, the apparent VH signal found can indicate elongation in geometry of the particles or anisotropic properties of the micelle core.

Self-Healing property of Bessel beams
Marie Solange Tumusange, Dr. Andy Chong
University of Dayton
A Bessel beam is a non-diffracting optical beam with many rings and whose amplitude is described by a Bessel function.  A Bessel beam can be easily generated by illuminating a Gaussian beam to a conic lens.  A Bessel beam shows self-healing when, distorted by an obstacle, the beam corrects itself upon propagation.  The self-healing property of a Bessel beam is studied by distorting the beam at one point and measuring beam profiles as the distorted beam propagates. The experimental results show that a Bessel beam recovers its Bessel function intensity profile after being partially obstructed.

Simulations of the Neutron Gas in the Inner Crust of Neutron Stars
Elizabeth Vandegriff, Charles Horowitz, Matthew Caplan
Taylor University
Inside neutron stars, the structures known as “nuclear pasta” are found in the crust. This pasta forms near nuclear density as nucleons arrange in spaghetti- or lasagna-like structures to minimize their energy. We run classical molecular dynamics simulations to visualize the geometry of this pasta and study the distribution of nucleons. In the simulations, we observe that the pasta is embedded in a gas of neutrons, which we call the “sauce.” In this work, we developed two methods for determining the density of neutrons in the gas, one which is accurate at low temperatures and a second which justifies an extrapolation at high temperatures. Running simulations with no Coulomb interactions, we find that the neutron density increases linearly with temperature for every proton fraction we simulated.

Two Dimensional Mapping of Nonlinear Emission from Superconducting Devices
Anna Wormmeester, Dr. Stephen Remillard
Hope College
Signal distortion from superconducting devices is caused by the nonlinearity of the superconductor, when multiple signals mix, resulting in intermodulation frequencies near that of the resonant frequency. The distortion products are expected to be generated at certain places in the device. Through mapping, the intermodulation hot spots can be located giving engineers a better sense of what is happening at certain parts of the superconducting device. A wide-line resonator was used to take measurements and to image the intermodulation distortion. The wide line resonator is folded into four lines, two in the middle and two on the outer edge, and all are connected through rounded edges. Multiple images were created to locate the intermodulation in the device. By refining the design of the raster probe, a better sense of where the distortion is coming from was gained. The probes that have been experimented with are small loop probe, a small loop probe with shielding, and a magnetic circuit probe. Local variations in distortion were not detected with the magnetic circuit probe. The probe with shielding has proven most effective, exhibiting less spurious signals. The couplers that provide the input signal are also a source of spurious signal.  A coupler that did not invade the device was tested. Based on the images produced, the intermodulation is localized as the probe moves across the transmission lines, and is strongest while the probe is over the transmission lines in the device This material is based upon work supported by the National Science Foundation under Grant Number DMR- 1505617
Last Updated: 8/28/19