The Windowless Gaseous Tritium Source for the KATRIN Experiment

For the direct, model-independent measurements of the absolute neutrino mass in an unprecedented sensitivity of 0.2 eV/c² the Karlsruhe Tritium Neutrino (KATRIN) experiment needs among other components a chain of superconducting magnet systems serving different purposes. The most complicated part of these magnets is the windowless gaseous tritium source (WGTS). Different calibration modes require that an electron beam from an e-gun is scanned over the active area. This scanning requires sets of dipoles allowing a deflection of the beam in horizontal and vertical direction. In order to reach the high precision in the measurement of the neutrino mass the operation of the source system must have extremely stable conditions. The magnetic field will have persistent mode operation and the beam tube must have a very sophisticated cooling system to keep the temperature within an extremely narrow range around the operating temperature of 30 K. This paper describes some of the design aspects of the WGTS.