RII Track-4: Development of high-purity Ge detector technology with LBNL for dark matter and neutrino physics

University Of South Dakota Main Campus, Vermillion SD

Investigators

Abstract

Non-technical Description Our understanding of the origins of the universe and the fundamental nature of matter are linked; however, our knowledge of those subjects is limited by the available instruments and their abilities to detect processes that occur at subatomic levels. The goal of this project is to initiate a long-term collaboration between the University of South Dakota (USD) and the Lawrence-Berkeley National Laboratory (LBNL) to develop novel detector technologies for experiments that aim to solve some of the most difficult questions in nuclear physics and cosmology, such as the true nature of dark matter, and how atomic nuclei are bound together. The proposed project will provide the PI with comprehensive training and experience on advanced detector development, and will establish needed collaborations to further his career. The proposed project also has the potential to establish a partnership between USD and companies that are interested in developing radiation detection technologies for a variety of applications, such as radiation therapy and/or homeland security. Given the increased capacity to develop these advanced detectors, USD may stimulate the interest of local industry in radiation detectors, thereby contributing to local economic development. Technical Description This collaborative research has two specific objectives: (1) measuring charge carrier drift mobilities in arbitrary directions for better modeling of electronic signal formation in High Purity Germanium (HPGe) detectors; and (2) investigating the possibility of particle identification utilizing ionization signal alone in HPGe detectors. They will be achieved through two years of collaborative development of a series of planar HPGe detectors and a variable temperature cryostat with low-noise front-end electronics by the PI and his graduate student in partnership with the host scientist in LBNL. The knowledge transfer during the collaboration will improve both the HPGe detector development capacity at USD, and the long-term competitiveness of USD in fundamental physics research. Detailed study of mobilities in different directions will lead to better theoretic understanding and numerical modeling of electronic signal formation processes in HPGe detectors, which is essential for signal/background discrimination in neutrinoless double beta (0νββ) decay experiments and for precise γ-ray tracking in nuclear spectroscopy experiments. Recently, a new collaboration, LEGEND, was formed as a merged effort of two state-of-the-art HPGe based 0νββ-decay experiments, GERDA and MJD, to establish a Large Experiment for Ge Neutrinoless double beta Decay search, using HPGe detectors. Both the home and host institutes joined the new collaboration. Their joint effort will help LEGEND obtain HPGe detectors with innovative properties from affiliated academic institutions to improve their sensitivities to 0νββ-decay signals.