Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 59: Struktur und Dynamik von Kernen

HK 59.7: Vortrag

Freitag, 23. März 2012, 12:45–13:00, P 4

Preparations for an optical access to the lowest excited nuclear state in ^229mTh^* — •Lars von der Wense, Peter Thirolf, Dominik Kalb, and Mustapha Laatiaoui — LMU München, Am Coulombwall 1, 85748 Garching

The isomeric lowest excited nuclear level of ²²⁹Th has been indirectly measured to be 7.6±0.5 eV (163±11 nm). In order to improve the accuracy as prerequisite of an all-optical control, ^229mTh is populated via a 2% decay branch in the α decay of ²³³U. The Thorium ions are extracted and cooled with the help of a buffer-gas stopping cell and an RFQ-cooler. In order to suppress accompanying α decay-chain products other than ^229mTh, a quadrupole mass spectrometer (QMS) is under construction, aiming at an optimum mass resolution and transmission efficiency. Following the QMS, the Thorium isomers will be collected on a 40 µ m needle tip. The decay of these isomers can then be detected using deep UV optics, presently under construction based on extensive simulations.

^* Supported by DFG Cluster of Excellence MAP.