The MAJORANA experiment and its follow-on, the Large Enriched Germanium Experiment for Neutrinoless Double-Beta Decay (LEGEND), search for the creation of matter in the form of neutrinoless double-beta decay, a process that would demonstrate that neutrinos are their own antiparticle and that lepton number conservation may be violated, allowing a deeper understanding of the matter-antimatter imbalance in the universe. MJ60 is a germanium detector used to investigate the low-energy region of the MAJORANA DEMONSTRATOR data, as well as the waveforms produced from incident betas in comparison with gamma events. The latter of these is important for understanding the background of LEGEND: the detectors are submerged in liquid argon, in which beta decays of argon-39 and argon-42 contribute to the background of the extremely sensitive experiment. MJ60 was originally a prototype for the P-type point-contact detectors used in the MAJORANA DEMONSTRATOR. Our group is using this detector to measure mechanisms of energy loss near the detector surfaces by recording events from the nearly monoenergetic beta emissions of metastable krypton-83 (83Kr) at 18 and ~30 keV. Analysis of the waveforms produced from these events, which has been my primary task, will allow us to investigate whether betas incident on our detectors’ passivated surface exhibit markedly different charge collection than gammas, as has been hypothesized. If this expectation is upheld, we will be able to produce a method to identify these events based upon a calculated parameter from the recorded waveforms. Such a parameter will help inform future detector R&D efforts, and will also contribute to background rejection capabilities in MAJORANA and LEGEND.

The COHERENT experiment is endeavoring to detect Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) in several nuclear targets using the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). We search for very low energy (on the order of keV) coherent interactions between neutrinos and atomic nuclei using an array of particle detectors made of different scintillating materials. Neutrinos are fundamental particles under the Standard Model of particle physics that historically have not conformed to theoretical expectations. Understanding their interactions with other particles helps us potentially find other unexpected qualities of neutrinos and in that, discover new physics. At the UW component of the COHERENT team, I along with several other physics undergrads, have just finished characterizing over one-hundred NaI(Tl) crystals to contribute to a large array of detectors at ORNL where they will be illuminated by a strong, pulsed flux of neutrinos born from pions and muons generated in the SNS beam target. For each crystal, I used two characteristic radioactive sources (133Ba & 137Cs) to gather data on each crystal for characterization of their use at ORNL. Each crystal was run for 1.67 hours to find the optimal operating voltage (gain) and to explore the energy linearity of radiation detections at different points in each 7kg crystal (this allowed us to identify if the crystals had any cracks that would interfere with detections). In this talk, I intend to present the statistics on the measured crystal characteristics, including gains, energy resolution, scintillation uniformity as we prepare to ship the crystals to ORNL for installation in the array of other detectors capable of detecting the CEνNS phenomenon.

The hypoxia response pathway, induced by genetic activation or by decreasing oxygen available, has been shown to extend the lifespan of C. elegans. A previous experiment conducted in our lab compared the transcriptomes of worms treated with normoxia, continuous hypoxia, and intermittent hypoxia therapy (IHT). This study showed that IHT doubles lifespan in C. elegans and was partially controlled by the enzyme inositol polyphosphate multikinase (IPMK-1), which suppresses some of the lifespan extension benefits of IHT. To further explore the genetic basis for the effect of IPMK-1 on IHT, we performed a forward genetic suppressor screen on the IPMK-1 animals. IPMK-1 animals die at elevated temperature so we mutagenized IPMK-1(sea9) worms and selected animals from the F2 generation that reached adulthood at 26.5^oC. Identifying the genetic changes in these suppressors will tell us more about the control of IHT and how it promotes longevity.

A 2019 study by Lobas, et al. demonstrated that a circularly permuted form of Green Fluorescent Protein (GFP) can be created such that it only fluoresces when bound to adenosine 5’ triphosphate (ATP), thereby acting as an observable ATP sensor. The primary source of ATP production in cells is in the mitochondria, and loss of mitochondrial function is considered a hallmark of aging. Because ATP additionally reflects the energetic availability of tissue in multicellular animals, it is of interest to study how ATP levels change in an organism throughout aging and in response to environmental stressors. This study uses a novel plasmid construct that has been optimized to express the fluorescent ATP sensor in the nematode C. elegans. These nematodes are visualized using our fluorescent imaging robot to measure ATP levels throughout the whole lifetime of the worms in order to determine if cellular ATP levels serve as an aging biomarker. The first construct uses whole body expression of the ATP sensor, which is expected to show varying levels of ATP-reporting fluorescence throughout the life of each animal before darkening in response to age-induced paralysis and death. Subsequent studies employ different promoters in the plasmid to create tissue-specific fluorescence. This allows for a wide combination of experiments that test the effect of environmental, temporal, and genetic factors on specific tissue ATP levels and longevity in C. elegans. For example, expressing the ATP sensor in hepatocytes in organisms under cyanide conditions indicates the energetic response of these cells to toxin. Results from these follow-up studies indicate how cellular energy affects organisms’ lifespans and the ability to respond to stressors, as well as the role that varying biochemical pathways play in maintaining energetic homeostasis during aging.