Spectroscopy of the proton drip-line nucleus ²⁰³Fr

U. Jakobsson, S. Juutinen, J. Uusitalo, M. Leino, K. Auranen, T. Enqvist, P. T. Greenlees, K. Hauschild, P. Jones, R. Julin, S. Ketelhut, P. Kuusiniemi, M. Nyman, P. Peura, P. Rahkila, P. Ruotsalainen, J. Sarén, C. Scholey, and J. Sorri

Accepted Monday May 6, 2013

The nucleus 203Fr has been studied through g-ray and electron spectroscopy, using the recoil-decay tagging technique. A 13/2+ state, with a half-life of 0.37(5) micro-s, has been observed in 203Fr for the first time. Both the a-decay branch and the internal de-excitation of the 1/2+ isomer in 203Fr have been studied. Furthermore, the corresponding 1/2+ state, with a half-life of 0.31(8)s, has been found in 199At. In addition, transitions feeding the 9/2- ground state of 203Fr have been identified. The observed level pattern suggests that the ground state is still spherical.