The first major achievements of SENSE are world-leading searches for eV-scale sterile neutrinos based on the first five data taking campaigns of KATRIN. These outcomes are highly complementary to other searches, which are typically based on short-baseline neutrino oscillation experiments. No eV-sterile neutrino signal was observed, setting stringent limits on the preferred parameter space of eV-scale sterile neutrinos.
A second major achievement of SENSE is the search for keV-scale sterile neutrinos based on an initial low-statistics commissioning dataset. The low rates during this measurement allowed to use the current focal plane detector of KATRIN. Based on this data set a leading limit on sterile neutrinos with a mass of around 1 keV could be set.
The third major achievement is the development, commissioning, and characterization of a novel multi-pixel Silicon Drift Detector system (named TRISTAN). This development included 1) the design and production of 166-pixel SDD chips with an integrated amplification at the Semiconductor Laboratory of the Max Planck Society, 2) the development of high-density front-end electronics, including dedicated ASIC chips, 3) the development of a high-performance Data Acquisition system, and 4) the construction of the mechanical holding and cooling infrastructure. Moreover, a number of dedicated calibration systems and test stands were developed to characterize the system. Our tests show an excellent performance of the system with respect to energy resolution and stability. An installation in a full replica system of the KATRIN detector section shows excellent performance in a realistic environment. The final installation of the 9 TRISTAN modules (each 166-pixels) is scheduled for 2026.
