The Tritium Recoil-Ion Mass Spectrometer (TRIMS) experiment is designed to measure the branching ratio of molecular tritium to the helium-tritium molecular ion after beta decay. Tritium emits very low-energy beta particles and is difficult to detect. My research seeks to measure the background levels of tritium contamination on laboratory and apparatus surfaces by using a gas flow proportional counter. This type of counter consists of a gas filled metal tube with a high voltage wire in the center. Beta particles from tritium decay ionize the gas, and the high electric field causes avalanche multiplication, which is picked up as a signal on the wire. The size of the signal is proportional to the energy of the original particle. This apparatus allows for surveys for tritium contamination initially and throughout the lifetime of the TRIMS experiment, with real time indication.

As magnetohydrodynamic (MHD) systems exhibit incredible nonlinearity, computational models have become increasingly common for parsing difficult engineering problems in plasma experiments. The dynamic mode decomposition (DMD) is a principled, data-driven, equation-free approach to extracting coherent temporal-spatial structures from raw data, with particular success in hydrodynamics and fluid-flow problems. We consider the DMD applied to MHD systems in the particular example of spheromak plasmas simulated in the Helicity Injected Torus experiment. We find that the DMD successfully resolves magnetic field structures in simulated magnetic field measurements that closely match expected physical properties. We further find that, under certain constraints, the DMD provides a powerful tool for further validation of simulation to experiment. Given the nonlinearity of magnetohydrodynamic systems, existing mechanisms for feedback controlling plasmas as instabilities occur are limited. Because the dynamic mode decomposition effectively serves as an approximate, linear reduced order model built from experimental and simulated magnetic field measurements on the fly, it offers considerable promise as a predictive feedback controller. This is significant as the detection of and control over plasma instabilities remains a major barrier to the use of spheromaks for fusion energy.

When two-dimensional materials, such as graphene, boron nitride, or transition metal dichalcogenides (TMDs) are stacked on one another, van der Waals forces bind the layers together to form vertical heterostructures. These have recently sparked interest in the device physics community. Heterostructures fabricated with two differing layers of transition metal dichalcogenides with type-II band alignment are of particular interest as they allow for the hole and electron to separate and be localized into the different monolayers of the heterostructure. Further, the separated charge carriers may bind together to form spatially indirect excitons at the interface. This species of exciton has been shown to exhibit a number of interesting properties including long-range drift-diffusion in the 2D plane, long-lived valley polarization, and an increase in the interlayer exciton lifetime by many orders of magnitude in WSe2–MoSe2heterostructures. A long exciton lifetime is particularly important for investigations of excitonic superfluidity and condensation, which are exciting phenomena in fundamental scientific research. Here, we use a hexagonal boron nitride (h-BN) monolayer to further separate the layers of the WSe2-MoSe2heterostructure and measure the change in the interlayer exciton lifetime. If the lifetime is long enough and exciton density high enough, these bound states can cool and condense into a degenerate Bose gas that exhibits superfluidity. We investigate the interlayer exciton lifetime in the MoSe2–h-BN–WSe2heterostructure by time-resolved photoluminescence. Further, the power dependence of the spatial distribution of the interlayer exciton photoluminescence will elucidate how these excitons migrate throughout the sample, which demonstrates the exciton superfluid phase transition. This research provokes further exploration into interlayer exciton condensation and other quantum-correlated effects in 2D heterostructures.

The nitrogen-vacancy (NV) center is a defect in diamond which shows promise as a solid-state qubit for scalable quantum computation. However, inhomogeneity and instability in the frequency of NV optical emission inhibits efficient quantum entanglement generation between NV centers, thus preventing the realization of quantum algorithms. This work implements two methods—one passive, one active—to mitigate these effects. First, high-temperature annealing improves the uniformity of the carbon lattice, which stabilizes the electro-magnetic environment of NV centers. Specifically, detrimental defects occupying nearby lattice-points diffuse out of the crystal. We build and test a system capable of non-destructively annealing diamond to 1200°C. Second, the application of strong local electric fields across NV centers enables active frequency control via the Stark Effect. To apply these fields, we fabricate gold electrodes directly on the surface of diamond containing near-surface NV centers. To determine the effectiveness of this method, we monitor the frequency of NV emission with photoluminescence excitation spectroscopy while fluctuating the applied electric field. Future work will involve the integration of these two systems with previously-demonstrated photonic circuits to realize efficient multi-qubit entanglement generation.

An electron bound to a donor impurity in a semiconductor exhibits properties of a quantum system that could be used as a spin quantum bit (qubit) for quantum computing. For such a quantum system to be considered a candidate for a spin qubit there must be minimal interaction with its surrounding environment, maximizing the time the system can store quantum information. Longitudinal electron spin relaxation time (T1), the characteristic time for perturbed electron spins to return to thermal equilibrium, serves as a fundamental upper limit for quantum information storage time of an electron spin qubit. Theoretical calculations and previous electron spin resonance measurements of donor bound electrons in bulk ZnO provide promising predictions for long storage times of ZnO donor electrons. To date there has been no direct optical measurements of T1 for donor bound electrons in ZnO. Here I present the experimental method and results of measuring T1 for electrons bound to gallium and indium donor impurities in ZnO nanowires. A measurement of T1 on the order of milliseconds for donor bound electrons in ZnO would merit further research to determine if these donor electrons can be realized as qubits with good properties. The nanowire structure of our ZnO samples also has the potential to meet another requirement for the donor bound electrons to be considered candidates for spin qubits; they must have qubit-specific measurement capabilities. By isolating a single nanowire, with the right sample dopant concentrations, we would be able to spatially resolve a single qubit.

Our lab is using the nitrogen-vacancy (NV) center, which is a specific impurity in diamond, to measure magnetic fields on a microscopic scale. The ability to measure these fields unobtrusively and in real time will be a valuable tool for studying biological systems tagged with magnetic nanoparticles. The NV centers fluoresce when exposed to green light, but in the presence of a microwave field of a specific frequency this fluorescence decreases. The precise frequency at which this occurs is dependent on the local magnetic field strength and direction. Thus, by sweeping this microwave field over a range of frequencies, we can measure the magnetic field at the NV centers. Here we use computer software, HFSS, to design a resonator to produce the necessary microwave field. Critically, the resonator needs to produce a uniform microwave field over the imaging area on a diamond chip for a wide frequency bandwidth. It also needs to integrate with other aspects of the overall design; in particular it should be transparent at the center to allow us to image through it. Designs are fabricated at the University of Washington MakerSpace, and a comparison between the simulations and these fabricated devices will be presented.

This project aims to build a pulsed laser for lifetime measurements of nitrogen-vacancy (NV) centers in diamond. Such measurements are an important tool for characterizing the quantum information processing potential of NV-center-based photonic devices. Specifically, the radiative lifetime of an NV center is indicative of the proportion of photons being emitted at the useful zero phonon line (ZPL) wavelength. Optical emission at other wavelengths cannot be used for quantum information processing. As NV centers naturally emit only ~3% of photons at the ZPL wavelength, a major objective of our lab is to increase this quantity through photonic integration. Although lifetime measurements have been performed previously in our lab, the excitation source used had a pulse width of 4 ps, much shorter than needed and thus requiring a high optical intensity. This tended to damage the photonic devices under investigation. Therefore, a pulsed laser with a pulse width on the order of 10 ns is being constructed for future lifetime measurements. An important feature of this laser will be a pulse fall time significantly shorter than the NV center’s radiative lifetime. After the laser becomes operational, we will utilize it to implement lifetime measurements of NV centers coupled to photonic devices. This will lead to a better characterization of device performance, and ultimately to large scale NV-center-based quantum information processing.

Clusters of rocket motors are classically arranged cylindrically for the purpose of maximizing the effective aerodynamics of the overall cross-sectional design. Alternatively, our team’s rocket booster engine configuration was arranged in a unique square formation around the main engine for the first stage of our launch. This not only simplified construction and reduced the need for extra material to support the engines, but also lent itself to increased stability by making use of the corners of the square as part of the fin design. This first stage consisted of nine identical motors ignited simultaneously. Once the second stage ignited, this nine-engine cluster detached from the rocket and propulsion continued via a single motor. Speeds reached approximately 550 m/s, which is to say approximately Mach 1.6. The mainframe was constructed of carbon fiber with Kevlar reinforcement to prevent the fins from self-destructing upon breaking the sound barrier and/or ground impact. Our payload consisted of electronics for measuring and transmitting acceleration, speed, and altitude, along with a GPS unit for tracking purposes. The rocket's objective was to reach 60K feet, the maximum altitude allowed by FAA regulations, with a supersonic square cluster design modeled after SpaceX’s Falcon9. The research conducted was to study the takeoff, flight stability, and landing of our rocket’s more efficient square orientation in comparison to a typical cylinder design.

The goal of the Project 8 experiment is to measure the neutrino mass scale using a new technique, Cyclotron Radiation Emission Spectroscopy (CRES), which requires a precise knowledge of the magnetic field within the apparatus. The signals from the experiment are located in the microwave region of the electromagnetic spectrum, which is also where electron spin resonance (ESR) can be used to measure magnetic fields. The ESR effect takes advantage of the behavior of unpaired electrons in chemical compounds. When an electron is in an external magnetic field its magnetic moment has two possible orientations: parallel or antiparallel to the field. These orientations correspond to two different energy levels. When microwave radiation is applied to the electron energy transitions between the two levels can be induced and energy is absorbed, flipping the direction of the magnetic moment. This resonance frequency is proportional to the magnetic field at the position of the sample. I have developed a new type of magnetic field sensor to replace the ESR probe currently installed in the Project 8 experiment. The new probe is constructed from coaxial waveguide with a small diameter that allows the probe to be close to the electron-trapping region without interfering with other instruments within the small diameter bore of the magnet. This probe also employs the chemical BDPA, with an absorption curve that is more symmetric and narrow than the chemical used in the old probe, DPPH. A mixture of BDPA and epoxy glue is used to replace a cylindrical section of the waveguide dielectric providing a precise knowledge of the sample position and geometry. I will present the design, test measurements, and initial results obtained with the coaxial ESR probe. Furthermore, I will discuss the incorporation of the new probe into the next generation Project 8 experiment.

In this experiment, the period of a complex pendulum was examined. The pendulum consisted of a long thin rod (physical pendulum) suspended from a pivot with a simple pendulum (a string of negligible mass holding a pendulum bob) suspended from the bottom of the physical pendulum. After release, the motion of the double pendulum is irregular and chaotic for a period of time until which the two pendula synchronize and behave as a single pendulum. It was hypothesized that the synchronization period of the complex pendulum would be longer than the natural period of the individual physical pendulum, due to the increased length. Initial findings indicate that when the length of the string of the simple pendulum and the angular displacement of the physical pendulum remain constant, the synchronization period of the system can be modeled as a simple pendulum and the synchronization time is constant. Further analysis of the complex pendulum will be conducted to examine how varying the simple pendulum length and the initial displacement impact the synchronization time and synchronization period to verify the synchronized simple pendulum model and further explore the complex nature of the system. Understanding the synchronization of chaotic systems can lead to the engineering of more complex systems.

The principal technological problem of the renewable energy industry is how to supply energy at its rate of demand and at a marginal cost less than that of present energy storage systems. One of the greatest challenges of this problem is the necessity of storing a portion of total produced energy such that it can be used when the instantaneous rate of energy demand differs from the limits of its instantaneous rate of production to balance out the demand and supply for energy. Our research focuses on the storage problem of current Under Water Compressed Air Energy Storage (UW-CAES) systems; in particular on decreasing the costs and environmental impact of air storage by performing electrolysis in a deep-sea electrolyzer to capitalize on the extreme energy densities already-available at depth and increase the energy density of each storage vessel/balloon by storing both hydrogen and oxygen. We demonstrate a method that increases the efficiency of energy storage by performing electrolysis using the high pressures available at depth, thereby eliminating the use of costly compressors and create a condition for the apparatus to be as close to a thermo neutral state.

Global Positioning System (GPS) technology has revolutionized the way we navigate our world, yet there remain many practical geolocalization problems for which the technology is not directly useful, such as in urban environments and scientific field work where GPS satellite L.O.S. (line-of-sight) obstructions are ubiquitous. Motivated by our collaborations with the LEAF School of Anthropology, our work is focused on providing technological solutions for cm-scale GPS-like geolocalization; particularly for researchers doing field work in prohibitive and complicated field topologies through the use of field-configurable ad-hoc geolocalization subnetworks. We present our work on and our methods to utilize time-of-flight measurements from GPS-enabled acoustic and radio frequency sources placed at the boundaries of the field of interest to determine the geographical coordinates of any number of locations within that field.

Factors such as temperature, pressure, presence of a catalyst, and reactant concentration are all known to affect the rate of chemical reactions and are well exploited in industry to drive chemical synthesis to favor certain mechanistic pathways. Here we consider the effect of using magnetism to control the rate of reaction for the Briggs Ruascher reaction. This reaction was chosen as a model for magnetic manipulation because it is mediated by both radical and non-radical pathways that compete with oscillatory behavior to produce the same product. Dramatic color changes serve as a visual cue to indicate which path is dominating. Here we put forth magnetic radical arrest hypothesis for the Brigg’s Ruascher reaction. It is known that electrons act like tiny magnets that pair with opposite spins. Because radical species carry a lone unpaired electron, presumably their magnetic fields are not concealed. We proposed that due to the exposed nature of the unpaired radical electrons in the Briggs Ruascher reaction, the progress of the reaction would be affected by the application of a magnetic field. Upon exposure to strong magnets, the radical intermediates of the Briggs Ruascher reaction were expected to aligned their spins with the applied magnetic field affecting their reactivity. Several types of neodymium magnets with various strengths were applied to the reaction in order to determine whether magnetism could prevent or greatly reduce the velocity of the color phase changes for the radical mediated portion of the reaction. We also built an electromagnet to expose the reaction to in order to achieve even greater field strength. The Brigg’s Rouscher reaction was found to be significantly robust and there was insufficient evidence to suggest that the reaction was affected by neodymium fields below a range of 5.8 mT. Results of exposure to the electromagnet are still in progress. The color changing cycles of the Briggs Ruascher reaction were found to follow a decreasing sigmoid mathematical model before going to completion after 9-10 oscillations.

The Large Hadron Collider (LHC) is one of the largest physics experiments in the world, and is best known for the discovery of the Higgs Boson. At the LHC, specialized sensors are used to detect high energy particles as they move away from beam collisions centered in detectors placed around the complex. These sensors are similar to what you would find in a standard camera; however the sensors are tuned to detect particles other than photons. The current sensors in the LHC are slowly degrading from radiation, and are built on an old outdated process. A new sensor is being designed which will not be compatible with the current sensor, requiring a new control system. The project is  focused on building a control system for a model of a candidate replacement sensor. Once the actual replacement sensor has been produced, the control system will be able to assist the testing and validation process of the physical sensor. The emulator control system I have designed offers a high speed method to test the emulated sensor, providing an interface between a host computer and the sensor. The control system is designed to be modular in order to allow researchers to use the design on a variety of different field programmable gate arrays (FPGAs) if more speed is required. The design of the control system has been completed and tested, and is currently being inegrated into the sensor mode, creating a full readout system. The creation of a fully emulated readout system is an essential step in improving the results gathered by the detectors in the LHC. 

The Hidden Valley is a new theory that extends the Standard Model, our current best description of particles and forces that make up our universe. The Hidden Valley theory, along with others, extends the Standard Model in an attempt describe phenomena like dark matter not yet included in the Standard Model. Hidden Valley particles do not interact with Standard Model particles, and are therefore impossible to directly detect. But by using their predicted decay products, we may be able to prove their existence. We are currently running simulations to try to give us an idea of what we should be looking for when we use data from the Large Hadron Collider at CERN. Features of the model and the search strategy will be presented.

An ion trap uses electromagnetic fields to trap charged particles in vacuum. We use an ion trap in this way to implement qubits (quantum bits) for quantum operations. Barium (Ba) and ytterbium (Yb) are promising candidates because their photoionization and cooling laser, optics and fiber optics are commercially available and in the visible spectrum. The micro-fabricated surface ion trap confines long chains of ions which are potentially scalable for running real and useful quantum algorithms and building a quantum computer. The current trap can confine Ba-Yb/Ba-Ba ion chains in a harmonic oscillator. As the number of ions increases, the ion chain will form a zigzag pattern and make uniquely addressing an individual ion for quantum gates with a laser beam impossible. But, quartic anharmonic oscillator can produce equal ion-ion spacing. My project can minimize quantum operation errors for quantum gates operation. I find the solutions for the DC electrode voltages numerically, using and improving the existing Boundary Element Method to generate a quartic anharmonic trap. Then, starting from the initial harmonic trap, I use the solution to morph the real trap potential into the quartic one. The changes of ion-ion positions are compared and verified using an EMCCD camera. Then, I determine the resonant frequencies of the ion chains in both the original (harmonic) and the modified (anharmonic) traps. The resonant frequency stays the same for the harmonic trap, but decreases in the quartic anharmonic trap as more ions are added to the chain. In conclusion, the quartic anharmonic trap has constant ion-ion spacing and overcome the zigzag issue which increases our ability to control qubits for quantum operations.