Decay of 201-203Ra and 200-202Fr
Abstract
Decay properties of the neutron-deficient nuclides 201-203Ra and 200-202Fr were investigated using α- and γ-decay spectroscopy. The nuclei were produced in fusion-evaporation reactions of 56Fe projectiles with enriched 147Sm and 149Sm targets at the velocity filter SHIP at GSI in Darmstadt (Germany). The α decay from the (3/2-) state in 201Ra was identified with an energy Eα=7842(12) keV and half-life T1/2=8-4+40 ms. Ambiguous decay properties for 202Ra from previous measurements were clarified by remeasuring with significantly improved precision, resulting in values of Eα=7722(7) keV and T1/2=3.8-0.8+1.3 ms. New short-lived isomeric states were identified in 200Fr and 201Fr with half-lives of 0.6-0.2+0.5 μs and 0.7-0.2+0.5 μs, respectively. A tentative spin and parity of 13/2+ were assigned to the latter. One event attributed to β-delayed fission of 200Fr was observed.
- Publication:
-
Physical Review C
- Pub Date:
- May 2014
- DOI:
- 10.1103/PhysRevC.89.054312
- Bibcode:
- 2014PhRvC..89e4312K
- Keywords:
-
- 23.60.+e;
- 23.20.Lv;
- 21.10.Tg;
- 27.80.+w;
- Alpha decay;
- gamma transitions and level energies;
- Lifetimes;
- 190<
- =A<
- =219