Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 33: Astroparticle Physics 1

HK 33.3: Vortrag

Dienstag, 24. März 2015, 18:00–18:15, P/H2

First Penning-trap mass measurement of the electron capture nuclide ¹⁶³Ho and its daughter ¹⁶³Dy for the ECHO project — •Fabian Schneider and the TRIGA-SPEC Collaboration for the ECHo collaboration — Institut für Kernchemie und Institut für Physik, Johannes Gutenberg-Universität Mainz

The ECHo (Electron Capture of ¹⁶³Ho) project aims to determine the mass of the electron neutrino by measuring the calorimetric spectrum of ¹⁶³Ho. To be able to extract the neutrino mass from the spectrum near the endpoint a precise knowledge of the decay Q-value is necessary. The ideal way to measure this in a model independent way is by high-precision Penning-trap mass spectrometry.

The ECHo collaboration has ¹⁶³Ho samples available, which were produced by reactor neutron irradiation. Such samples are typically highly contaminated with radioactive and stable species. These were efficiently removed by chemical purification. Ionization by laser ablation allows high-precision Penning-trap mass measurements with sample sizes of 10¹⁶ atoms. From the measured cyclotron frequency ratio of ¹⁶³Ho¹⁶O⁺ to ¹⁶³Dy¹⁶O⁺ we determined the Q-value to be 2.5(7) keV. In addition absolute mass measurements using carbon cluster ions as reference were performed with an uncertainty two times lower than literature values.

Future measurements at SHIPTRAP (GSI, Darmstadt) and PENTATRAP (MPIK, Heidelberg) are planned with the aim to drastically improve the uncertainty of the Q-value down to a few eV and thus providing the required input for the ECHo project.