%0 Journal Article
%A Engels, Ralf
%A Büscher, Markus
%A Buske, Paul
%A Gan, Yuchen
%A Grigoryev, Kirill
%A Hanhart, Christoph
%A Huxold, Lukas
%A Kannis, Chrysovalantis
%A Lehrach, Andreas
%A Soltner, Helmut
%A Verhoeven, Vincent
%T Direct observation of transitions between quantum states with energy differences below 10 neV employing a Sona unit
%J The European physical journal / D
%V 75
%N 9
%@ 1434-6079
%C Heidelberg
%I Springer
%M FZJ-2021-03731
%P 257
%D 2021
%X The direct access to atomic transitions between close by quantum states employing standard spectroscopic methods is often limited by the size of the necessary radio-frequency cavities. Here we report on a new tool for fundamental spectroscopy measurements that can overcome this shortcoming. For this, a Sona transition unit was used, i.e., two opposed solenoidal coils that provide an oscillating field in the rest frame of the through-going atomic beam. In this way, we were able to control the induced photon energy down to 10 neV or f∼ MHz. The tuneable parameter is the velocity of the atomic beam. For illustration of the method, we report a measurement of the hyperfine splitting energies between the substates with F=1 and m_F=−1,0,+1 of 2S_1/2 metastable hydrogen atoms as function of a magnetic field.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000701695300001
%R 10.1140/epjd/s10053-021-00268-4
%U https://juser.fz-juelich.de/record/897325