$^{83m}$Kr N-line spectrum measurement at KATRIN

The 83mKr conversion electrons are used for calibration purposes of different (astro-)particle physics experiments due to the narrow 83mKr line widths and short 83mKr half-life. In the KArlsruhe TRItium Neutrino experiment (KATRIN), that currently provides the best neutrino mass upper limit of 0.8 eV/c2 (90% C. L.) in the field of direct neutrino-mass measurements, several systematic uncertainties are studied by a shape distortion of the quasi monoenergetic 83mKr spectrum. This creates high demands on precise knowledge of the undistorted spectrum.

In KATRIN we use the 32 keV N-lines lying in the high energy region of the spectrum including the weaker N1 line. In this talk, results of a dedicated measurement of the 83mKr electron N-spectrum with emphasis on N1 line position and width conducted at unprecedented precision at KATRIN will be presented.