KATRIN experiment
The KATRIN experiment aims to make an order of magnitude improvement in the directmeasurement of the mass of the neutrino complementing the model-dependent measurementsobtained via cosmology and searches for neutrinoless double beta decay. With a predictedsensitivity of 200 meV, KATRIN will investigate the neutrino hierarchy and address thevalue for the neutrino mass of 560 meV derived from a claimed observation of neutrinolessdouble beta decay1 . KATRIN is currently under construction at the Karlsruhe Institute ofTechnology (KIT) in Germany. Data taking is expected to begin in early 2014 with finalsensitivity reached 5 years later. KATRIN probes the neutrino mass by making a precisionmeasurement of the electron energy spectrum associated with beta decay of tritium. Neutrinomass is evidenced in a distortion at the high energy tail of the spectrum, allowing a value forthe mass to be derived solely from the kinematics of the reaction. The design of the KATRINapparatus draws on some 40 years of tritium beta decay searches for the neutrino mass. Theimproved sensitivity of KATRIN arises primarily from increases in source luminosity and thephysical size of the apparatus and probably represents the best one can practically expect toachieve with this technology.http://ewi.npl.washington.edu/katrin/