Periodic Reporting for period 3 - SENSE (Sterile neutrino search in tritium beta decay)
Berichtszeitraum: 2022-05-01 bis 2023-10-31
A promising way to search for eV to keV sterile neutrinos is via the kinematics of beta decay, where this new particle would manifest itself as characteristic spectral deformation. The Karlsruhe Tritium Neutrino (KATRIN) experiment operates one of the strongest tritium sources for scientific research. Its primary goal is a direct measurement of the absolute neutrino mass scale. It has recently published a world-leading direct limit on the neutrino mass of m < 0.8 eV.
The aim of the SENSE project is to extend the KATRIN experiment to search for eV and keV-scale sterile neutrinos. The former can be searched for with the data that is currently being recorded for the neutrino mass measurement. However, a keV-scale sterile neutrino search requires an upgrade of the focal plane detector system in the 70-m long KATRIN beamline. In the framework of SENSE we develop a beyond-the-state-of-the art multi-pixel Silicon Drift Detector focal plane array to be installed in the beamline after the completion of the neutrino mass program of KATRIN.
The second major achievement of the first funding period is the completion of the design of the multi-pixel Silicon Drift Detector array. We succeeded in operating a 166-pixel monolithic SDD array, which is the largest array that was ever built. Our tests show an excellent performance of the system with respect to energy resolution and stability. For the final installation in KATRIN, prospectiveley in 2026, nine 166-pixel arrays will be combined.
We except to largely improve our eV-scale sterile neutrino sensitivity with the upcoming KATRIN data sets. The next publication based on the first five data taking campaigns in planned for 2023. The full statistics will be collected by the end of 2025. The new detector system will be integrated thereafter in 2026. By the end of 2024, i.e. in the scope of the SENSE project, we expect to achieve the final construction of the full Silicon Drift Detector system, consisting of 9 arrays and a complete read-out and data acquisition chain.