4:00–6:00 pm
Sravan Munagavalasa's PhD Thesis Defense
Tuesday, November 3 at 4:00 PM CST
Search for Light Dark Matter Under the French Alps: Developing the DAMIC-M Readout Chain and Probing Benchmark Models
Astrophysical and cosmological observations provide overwhelming gravitational evidence for the existence of dark matter. However, its particle nature remains unknown. The DAMIC-M (DArk Matter In CCDs at Modane) experiment aims to detect sub-GeV light dark matter candidates using charge-coupled devices (CCDs) at the Laboratoire Souterrain de Modane (LSM). Paired with skipper readout, the CCDs can detect eV-scale energy depositions, while the roughly 1,700 m of rock overburden at LSM shields the detector from cosmic rays that would otherwise dominate the background. DAMIC-M is currently under construction and is expected to begin collecting data in 2027. A prototype detector, the Low Background Chamber (LBC), has been operating at LSM since 2022 to validate the detector design and readout chain and to perform initial searches for light dark matter.
This dissertation focuses on the development of the DAMIC-M readout chain, front-end electronics, and data acquisition system used to operate the skipper CCDs. It then describes the construction and commissioning of the LBC and the collection of science data for dark matter searches. Finally, it presents the analysis of LBC data, the first to probe benchmark models of hidden-sector dark matter produced through freeze-in and freeze-out mechanisms. These results demonstrate the capabilities of skipper-CCD detectors at LSM and lay the groundwork for the full-scale DAMIC-M experiment.
Committee members:
Paolo Privitera (Chair)
Juan Collar
Karri DiPetrillo
Gordan Krnjaic
Sravan will join UC Berkeley and LBNL as a postdoc, working on the development of quantum sensors and the construction of the TESSERACT experiment. He will continue to take trips to the French Alps to search for dark matter.