Abstract:

Tritium beta decay experiments provide the most sensitive direct measurement of the neutrino mass scale. There is a long history of this type of experiment, and it continues to be rened with two particular projects: the Karlsruhe Tritium Neutrino Experiment (KATRIN), and Project 8. KATRIN is currently being set up at the Karlsruhe Institute of Technology in Karlsruhe, Germany. It seeks to improve the sensitivity to the neutrino mass scale by an order of magnitude over the previous generation of tritium beta-decay experiments, down to 0.2 eV/c2. KATRIN will use a high-resolution spectrometer known as a MAC-E lter to carefully measure the beta- decay electron energy spectrum. The resolution of the spectrometer is limited by its physical dimensions, and KATRIN is the largest experiment of this type that can be built in the foreseeable future. Therefore a new approach is needed to further improve the sensitivity to the neutrino mass scale. Project 8 is an experiment in the early stages of R&D that will use radio-frequency techniques to detect and measure the energies of beta-decay electrons. We plan on measuring the coherent radiation created from the cyclotron motion of the electrons in a strong magnetic eld. As this technique involves a measurement of a frequency in a way that is non-destructive to the electron, we can, in principle, achieve a high degree of resolution and a further-improved sensitivity to the neutrino mass.