Commissioning of a pulsed UV photoelectron source at the KATRIN main spectrometer

The KATRIN experiment aims to measure the electron neutrino mass with a sensitivity of < 0.2 eV at 90% confidence level. The measurement is accomplished by scanning the endpoint of the tritium β-spectrum with an electrostatic spectrometer, based on the MAC-E-Filter (magnetic adiabatic collimation with an electrostatic filter). For the calibration of the spectrometer a mono-energetic, angular selective UV photoelectron source had been developed and constructed in Muenster (see K. Hugenberg, Prog. Part. Nucl. Phys. 64 (2010) 288). This electron source has been used in the successful commissioning of the main spectrometer and detector system in summer 2013. The poster presents the characteristics of the electron source determined during the spectrometer measurements.