Würzburg 2018 – scientific programme

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T: Fachverband Teilchenphysik

T 55: Neutrinophysik VII

T 55.4: Talk

Wednesday, March 21, 2018, 17:15–17:30, Z6 - HS 0.001

Commissioning measurements of the CKrS with KATRIN — •Alexander Fulst for the KATRIN collaboration — Institut für Kernphysik, WWU Münster

The KArlsruhe TRItium Neutrino Experiment (KATRIN) is a model-independent measurement of the neutrino mass from the kinematics of tritium β-decay, aiming for a sensitivity of 0.2 eV/c² (90% C.L.). It uses an electrostatic spectrometer working in MAC-E-filter mode to analyze energies of beta-electrons generated in a windowless gaseous tritium source (WGTS). The experiment uses several sources for absolute energy calibration, monitoring and precise determination of the transmission function of the spectrometer. One of them is the Condensed Krypton Source (CKrS) developed in Münster which utilizes nearly monoenergetic conversion electrons from an adsorbed ^83mKr layer on a graphite (HOPG) substrate. The substrate with the frozen ^83mKr layer can be moved mechanically over the complete flux tube area at its position in the KATRIN beamline and therefore allows for per-pixel calibration of the KATRIN focal plane detector (FPD). The cleanliness of the substrate and the quality of the frozen radioactive films are crucial for the stability and reproducibility of the conversion electron spectrum and both are monitored by means of laser ellipsometry.

The source was recently installed at the KATRIN Cryogenic Pumping Section (CPS) and was successfully used in the KATRIN commissioning measurements in the summer 2017. Measurements regarding characterization of the source and spectroscopy with the CKrS are presented. This work is supported under BMBF contract 05A17PM3.