Speaker
Description
The LEGEND (Large Enriched Germanium Experiment for Neutrinoless double beta Decay) experiment aims at the detection of the neutrinoless double beta decay, which, if observed, would lead to groundbreaking implications in neutrino physics and in cosmology. Located at Laboratori Nazionali del Gran Sasso, Italy, the experiment will discover if the neutrino is a Majorana particle (i.e. it coincides with its own antiparticle), reaching a sensitivity to the half-life of the decay of 10^27 years in the first phase, LEGEND-200, and of 10^28 years in the second phase, LEGEND-1000. The first phase aims to employ 200 kg of high-purity germanium (HPGe) detectors enriched in 76Ge, the double beta emitter, and started data-taking in March 2023, with a run-time of five years. The second phase will operate 1000 kg of HPGe detectors and plans to be operative in 2030, with a designed run-time of ten years.
The germanium detectors are contained in a cryostat filled with liquid argon (LAr). The LAr instrumentation is an important apparatus of the experiment, responsible for collecting the scintillation light generated by the background particles interacting with the LAr. Wavelength-shifting reflector (WLSR) materials are important to shift the wavelength of the light, so to enhance the match with the optical sensors, and to reflect light back to the optical sensors themselves.
My project is to study and characterize WLSR materials for LEGEND-1000 and will be important for the final selection of the material. The new materials I will investigate include polyethylene naphtalate (PEN), thin films based on polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET), and white reflective paints which could also be considered for the cryostat covering. I am evaluating the optical and mechanical properties, the radiopurity and the possibility to scale to large dimensions of the candidate samples I have collected, considering the larger size of LEGEND-1000. My studies will not only be useful for LEGEND-1000, but could also be valuable for future large-scale LAr scintillation experiments, considering that LAr-based experiments often need radiopure WLSR surfaces to enhance the LAr scintillation light collection without introducing additional background.
| Collaboration(s) | LEGEND Collaboration |
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