Since the discovery of neutrino oscillation we know that neutrinos have non-zero masses, but we do not know the absolute neutrino mass scale, which is as important for cosmology as for particle physics. The direct search for a non-zero neutrino mass from measuring the endpoint spectra of weak decays is complementary to the search for neutrinoless double beta-decay and analyses of cosmological data.
The Karlsruhe Tritium Neutrino experiment KATRIN is investigating the endpoint region of tritium beta decay. KATRIN uses a strong windowless gaseous molecular tritium source combined with a huge MAC-E-Filter as high resolution electron spectrometer. To achieve its neutrino mass sensitivity goal of 0.2 eV/c^2, KATRIN has been putting many technologies at their limits and uses elaborated calibration techniques.
From early 2019 on KATRIN is taking high statistics tritium data hunting for the neutrino mass. Already its data of 2019 provide a sub-eV sensitivity and neutrino mass limit. In addition to the presentation of the current status and results of KATRIN, an outlook on future improvements and enlarging the KATRIN program to keV sterile neutrinos will be given in this talk.