Hamburg 2016 – scientific programme

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T: Fachverband Teilchenphysik

T 50: Neutrinomasse II

T 50.1: Talk

Tuesday, March 1, 2016, 16:45–17:00, VMP5 SR 0079

Separation and Implantation of the Rare Isotope ¹⁶³Ho — •Tom Kieck¹, Katerina Chrysalidis¹, Holger Dorrer¹, Christoph Düllmann^1,2, Lisa Gamer³, Loredana Gastaldo³, Stefan Kormannshaus¹, Sebastian Schmidt¹, Fabian Schneider¹, and Klaus Wendt¹ for the ECHo collaboration — ¹JGU Mainz — ²GSI Darmstadt — ³Universität Heidelberg

The ECHo collaboration aims at measuring the electron neutrino mass by recording the spectrum following electron capture of ¹⁶³Ho. To reach a sub-eV sensitivity, a large number of individual microcalorimeters is needed, into which the isotope must be implanted in a well-controlled manner. The necessary amount of ¹⁶³Ho is produced by neutron irradiation of enriched ¹⁶²Er in the ILL high flux reactor. This introduces significant contaminations of other radioisotopes, which have to be quantitatively removed both, by chemical and mass spectrometric separation. The application of resonance ionization at the RISIKO mass separator guarantees the required isotope selectivity for purification and suitable energy for ion implantation. The efficiency and stability of the laser ion source was improved by Finite-Element Analysis of the thermal processes. For optimum implantation into the detector pixels (170 × 170 µ m²) with minimum losses a small ion beam spot at the implantation site is needed. For this purpose, post focusing ion optics were installed. Simulations were performed in order to optimize the homogeneous distribution of the implanted ions. The necessity to alternate implantation phases with deposition of a thin metallic layer for ¹⁶³Ho activities larger than 10 Bq is being discussed.