Gießen 2024 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 52: Structure and Dynamics of Nuclei X
HK 52.4: Vortrag
Mittwoch, 13. März 2024, 18:15–18:30, HBR 19: C 5a
Studying the internal conversion decay of the 229Th isomer in the bulk of VUV-sensitive SiPMs — •Lilli Löbell1, Daniel Moritz1, Georg Holthoff1, Mahmood Hussain1, Sandro Kraemer1, Tamila Rozibakieva1, Kevin Scharl1, Benedict Seiferle1, Lars von der Wense2, Markus Wiesinger1, and Peter G. Thirolf1 — 1Ludwig-Maximilians-Universität München — 2Johannes-Gutenberg-Universität Mainz
229Th has a nuclear isomer with an exceptionally low excitation energy of only 8.338 ± 0.024 eV (λ = 148.71 ± 0.42 nm). This makes 229mTh the so far only candidate for a nuclear clock, which has potential applications ranging from dark matter research and searching for a time dependence of fundamental constants to improving geodesy and satellite-based navigational systems. For the decay of the thorium isomer to the ground state, the dominant decay channel in neutral 229mTh atoms is internal conversion (IC). The half-life of the IC decay measured on a metallic surface was found to be 7 ± 1 µs, but there are indications of a dependence on the electronic environment surrounding the thorium atom. We are currently investigating the IC lifetime of 229mTh within a solid state environment by implanting 229mTh atoms into the depletion region of VUV-sensitive silicon photomultipliers, where the IC electrons can be detected. In case of a significantly longer IC lifetime, this could be an approach for a solid-state nuclear clock based on internal conversion. The talk presents the current status of this project. This work was supported by the European Research Council (ERC): ERC Synergy Grant ’ThoriumNuclearClock’.
Keywords: Thorium-229; SiPM