Eur. Phys. J. A (2005) 23: 401-408
https://doi.org/10.1140/epja/i2004-10103-0

Total absorption spectroscopy of the β-delayed proton emitter ¹¹⁷Ba

¹ Institute of Experimental Physics, Warsaw University, PL-00681, Warsaw, Poland
² St. Petersburg Nuclear Physics Institute, 188-350, Gatchina, Russia
³ Gesellschaft für Schwerionenforschung, D-64291, Darmstadt, Germany
⁴ University of Edinburgh, EH9 3JZ, Edinburgh, UK
⁵ Continental Teves AG & Co. oHG, D-60488, Frankfurt, Germany

^* e-mail: janas@mimuw.edu.pl

Received: 4 October 2004
Accepted: 9 November 2004
Published online: 12 January 2005

Abstract

The very neutron-deficient ¹¹⁷Ba nuclei were produced in ⁵⁸Ni-induced reactions on a ⁶³Cu target and selected for spectroscopic studies by using BaF⁺ molecules formed in the ion source of the GSI on-line mass separator. The β-decay of ¹¹⁷Ba was investigated by means of the total absorption γ-ray spectrometer and a telescope for β-delayed particle detection. In the analysis combining the β-delayed γ-ray and proton data the energy window available for β-delayed proton emission, the branching ratios for proton transitions to the ¹¹⁶Xe levels and the β-feeding of the γ-ray and proton-emitting ¹¹⁷Cs states were determined. The β-strength function for ¹¹⁷Ba derived from the measured β-feeding distribution revealed the existence of a broad resonance structure at ¹¹⁷Cs excitation energy of about 4-5 MeV. The results of the β-delayed proton studies and β-strength measurements are confronted with theoretical predictions.