Precision high voltage monitoring for the KATRIN experiment

The KATRIN Experiment aims to determine the absolute mass of the electron anti-neutrino with a sensitivity of 0.2 eV. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor and calibrate high voltages of up to 35 kV with a precision and long-term stability at the 10⁻⁶ level. In order to solve this a monitoring scheme is being set up, consisting of a newly designed precision high voltage divider and a monitor spectrometer beam-line measuring a mono-energetic calibration source.