Feasibility study on the detection of the internal conversion decay of 229mTh in the bulk of VUV-sensitive SiPMs

by Lilli Löbell

Thursday 6 Jun 2024, 09:30 → 11:00 Europe/Berlin

E18/ENE Seminar Room 3268 (TUM PH)

229Th has a nuclear isomer with an exceptionally low excitation energy of only 8.35574(3) eV, which corresponds to a wavelength of 148.3821(5) nm. This allows for a laser excitation of the nuclear transition and makes 229Th a promising candidate for an ultra-precise nuclear clock with potential applications ranging from fundamental research to improving satellite-based navigational systems.

A further interesting property of the thorium isomer is the expected dependence of the lifetime of its internal conversion (IC) decay channel on the electronic environment surrounding the thorium atom. On a metallic surface, a half-life of 7±1 µs was measured, but there are indications for a dependence on the penetration depth. A possible way to investigate the IC lifetime in the bulk of a solid is the implantation of 229mTh atoms into the depletion region of a VUV-sensitive silicon photomultiplier, where the IC electrons can be detected. The talk presents a feasibility study on this approach for the detection of the IC decay of the thorium isomer.