  The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation,
model independent, large scale experiment to determine the neutrino mass by
investigating the kinematics of tritium beta-decay with a sensitivity of 200
meV/c2. The measurement setup consists of a high luminosity windowless gaseous
molecular tritium source (WGTS), a differential and cryogenic pumped electron
transport and tritium retention section, a tandem spectrometer section
(pre-spectrometer and main spectrometer) for energy analysis, followed by a
detector system for counting transmitted beta-decay electrons. To achieve the
desired sensitivity, the WGTS, in which tritium decays with an activity of
about 10e11 Bq, needs to be stable on the 0.1 % level in injection pressure and
temperature at an absolute value of about 30 K. With the capability to create
an axial magnetic field of 3.6 T the WGTS is going to be one of the world's
most complex superconducting magnet and cryostat systems. The main spectrometer
(length 24 m, diameter 10 m), which works as a retarding electrostatic
spectrometer, will have an energy resolution of 0.93 eV at 18.6 keV. For the
precise energy analysis at the tritium endpoint, a retarding potential of -18.6
kV is needed with 1 ppm stability. To reach the background level needed to
achieve the sensitivity, it will be operated at a pressure of 10e-11 mbar. This
article will give an overview of the KATRIN experiment and its current status.
