April 29, 2024
Indiana University graduate student, Sam Schleich, has been awarded a fellowship through the National Science Foundation’s Graduate Research Fellowship Program (GRFP). The GRFP is a prestigious program that supports exceptional graduate students who have demonstrated potential for significant research in STEM and STEM education. “The purpose of the NSF GRFP is to help ensure the quality, vitality, and diversity of the scientific and engineering workforce of the United States.” To find out more about this program, please visit the website.
Sam will conduct research on the Majorana Demonstrator and LEGEND experiments, which are precision rare event searches all primarily focused on neutrinoless double beta decay—a rare and hypothetical form of nuclear decay that would show the neutrino to be its own antiparticle. However, his research will take a unique approach to these experiments, instead focusing on other rare event searches.
The Majorana Demonstrator, located at the Sanford Underground Research Facility in Lead, SD, is one of the flagship germanium detector experiments across the world that sought to demonstrate the efficacy of using multiple germanium detectors in tandem to perform precision rare event searches. The Demonstrator is composed of multiple germanium detectors arranged into “strings,” which are locked away inside an electroformed copper shell, which is further shielded by a castle of lead bricks; all of this produces the world’s best environment to detect rare events with minimal background noise.
In 2021, the Majorana collaboration published its final results for its neutrinoless double beta decay campaign, setting competitive limits for the half-life of neutrinoless double beta decay in 76-germanium and showcasing that the Demonstrator has the highest energy resolution of any detector in the world and has world-class background levels.
Utilizing this, in 2022 the collaboration began a secondary campaign in the hopes to detect the decay of 180m-tantalum, a unique isomer that has a longer half-life than its ground state, making it an ideal candidate for interesting science. Here, as an undergraduate at South Dakota Mines, Sam helped in the rebuilding of the Demonstrator for this new experiment, which has since set the best lower-limit for the decay of 180m-tantalum by many orders of magnitude compared to past literature results. The Demonstrator also holds potential to observe other rare decays, such as the decay of zirconium-96 which is also predicted to exhibit similar excited-state decays.
LEGEND-200, the successor to Majorana located at LNGS in Italy, is even more sensitive than Majorana, which will allow Sam to further his search for certain excited state decays within the data collected. For the third-phase neutrinoless double beta decay experiment, LEGEND-1000, Sam will employ the laboratory skills he gained underground to design and construct gloveboxes that will be used to carefully construct large arrays of germanium detector strings.
