  The first observation of the kaonic 3He 3d - 2p transition was made using
slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were
detected with large-area silicon drift detectors using the timing information
of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The
strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2
(stat)+-4 (syst) eV.
