83mKr N-line spectrum measurement at KATRIN

Conversion electrons from 83mKr are used as a versatile calibration tool in a range of different (astro-)particle physics experiments. Favourable properties are the short half-life and narrow line spectrum of 83m-Kr as a nuclear standard. In the KArlsruhe TRItium Neutrino experiment (KATRIN) which currently provides the best direct neutrino mass upper limit of 0.45 eV/c2 (90% C. L.), 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. Results of a dedicated measurement of the 83mKr electron N-spectrum with emphasis on N1 line and adjacent shake lines will be presented in this talk.