β-delayed fission from 256Esm and the level scheme of 256Fm
Abstract
The 7.6-h isotope 256Esm was produced from a 2.5-μg/cm2 target of 254Es by the (t,p) reaction. The reaction products were separated radiochemically, and the decay properties of 256Esm were determined via β-γ, γ-γ, and β-fission correlation techniques. From these measurements we were able to assign 57 γ rays to 26 levels in the daughter 256Fm. An isomeric level was observed at 1425 keV and assigned a spin and parity of 7-. This level has a t1/2 of (70+/-5) ns and we observed two β-delayed fissions with delay times in the proper time range to be associated with fission from this level. This gives a β-delayed fission probability of 2×10-5 for this level and a partial fission half-life of 0.8+8.8-0.7 ms at the 95% confidence level.
- Publication:
-
Physical Review C
- Pub Date:
- May 1989
- DOI:
- 10.1103/PhysRevC.39.1866
- Bibcode:
- 1989PhRvC..39.1866H
- Keywords:
-
- 25.85.-w;
- 23.20.Lv;
- 27.90.+b;
- 97.10.Cv;
- Fission reactions;
- gamma transitions and level energies;
- 220<
- =A;
- Stellar structure interiors evolution nucleosynthesis ages