Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The MLL IonCatcher buffer gas cell facility forms the key component of our experimental efforts to study the isomeric ground state transition of the lowest nuclear excited state in 229mTh at 7.6(5) eV as described in the 2007 annual report [1]. There the goal is to exploit the unique properties of this lowest excited nuclear state with its unprecedented narrow relative linewidth of about 10−21 for metrology as well as for fundamental physics studies such as a potential time dependence of fundamental constants like the fine structure constant ). Using the gas cell as an 'isomer generator' from the – decay of 233U, the production of the 229Th isomers can be decoupled from the fluorescence decay of the isomeric first excited state in 229mTh, thus avoiding any background contaminations from atomic or conversion processes.