Optically Determine the Isomeric Engrgy of 229Th
The isotope 229Thorium is a crazy thing! Now, several groups around the world are its super fans: Los Alamos National Lab, Lawrence Livermore National Lab, UCLA, TU Vienna, PTB, Moscow State University, UNSW and MPIK. 229Th is expected to carry a very unique isomeric transition energy of 7.8(0.6)eV and extremely long lifetime of 6(1) hours. This means we have the opportunity to control nuclei simply by VUV lasers, and very long life of the isomer state also gives the tempting reason to build the extremely accurate nuclear clock. However, problem comes, so far nobody knows its exact transition energy, and lots of proposal have been designed. In Phys. Rev. Lett. 109, 262502 (2012) We propose a new and simple way to measure it by electromagnetically modified nuclear forward scattering. It turns out my scheme may not only catch the wanted isomeric energy with a very small uncertainty of 1kHz ~ 10Hz but also provide some additional bonus, e.g., directly measure the isomer magnetic moment and it also lays the foundation for developing nuclear quantum optics in 229Th.
(image credit: Dr. Thorsten Schumm)