VUV and laser ionization spectroscopy of the 229m-Th isomer: a step towards a nuclear clock

(ref. BAP-2022-541)

Laatst aangepast : 12/07/2022

The Institute of Nuclear and Radiation Physics (IKS) is active in the fields of nuclear physics for fundamental and societal research. It has about 50 researchers and 5 professors, and graduates 3-5 PhD students per year. The IKS expertise is situated in radioactive and stable ion beam research and applications, and nuclear physics research with laser, decay, orientation and reaction techniques. Within the IKS, the Nuclear Spectroscopy Group of Prof P. Van Duppen studies the fundamental nature of the atomic nucleus from the halo nuclei in the lightest elements to the actinides and super-heavy elements, from neutron-deficient to neutron-rich, employing various experimental techniques at CERN (CH), GSI (D), and GANIL (F). These includes laser ionization spectroscopy techniques, radiation detector systems and VUV spectrometry. A specific subject deals with the production and study of the thorium-229 isomer (229m-Th) a candidate for the development of a nuclear clock. The Nuclear Spectroscopy Group operates an in-house laser lab with high repetition rate pulsed dye laser systems and a mass separator lab for research on stable and long-lived radioactive isotopes.

Project

This PhD position is opened in the framework of the 229m-Th isomer study. This unique nuclear isomer at an excitation energy of around 8.3 eV (corresponding to a VUV transition of about 150 nm) should allow to built a nuclear clock that outperforms the precision of current atomic clock by at least an order of magnitude and exhibits unique properties to test fundamental physics. While this unique isomer has been proposed four decades ago, it is only a few years ago that its existence has been firmly established experimentally. 

At KU Leuven, a project was initiated to produce and study the 229m-Th isomer following two complementary routes. A new approach to produce pure samples of the 229m-Th isomer via laser ionization is under development in the local laser and mass separator labs, and the production of an intense source of 229m-Th populated via the beta decay of 229-Ac (produced at ISOLDE-CERN (Switzerland)) has been initiated. Both projects address complementary aspects and hold promising opportunities. However, in order to observe for the first time the radiative decay of the isomer and to determine its excitation energy with an order of magnitude better precision, a dedicated VUV spectrometer set-up has to be constructed and characterized specifically for the 229m-Th study. With this set-up, our group managed to detect for the first time the radiative decay of 229m-Th (which is an essential ingredient to develop a nuclear clock) and improved the uncertainty on the excitation energy by a factor of six. This project will continue along these lines by upgrading the VUV spectrometer to improve the uncertainty by another factor of 4 and by studying the isomer's half life in different large band gap crystals that can potentially serve as a proper host for the nuclear clock.

Profile

We are looking for enthusiastic and motivated candidates that have a background in physics or engineering studies. You will be fully integrated in the 229m-Th research group and take part in all aspect of the research. Skills in the field of laser physics, atomic physics, ion manipulation, VUV spectroscopy and nuclear physics will be developed in the course of the PhD training. Regular travels between the different partner laboratories (Vienna and CERN) will take place.

You have a Master degree in Physics or Engineering.

Offer

 We offer a full-time PhD grant for a period of 2 (plus 2) years.

Interested?

For more information please contact Prof. dr. Piet Van Duppen, tel.: +32 16 32 72 72, mail: [email protected].

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