β decay of V61,63 and low-energy level schemes of Cr61,63
Abstract
Background: Near N = 40, rapid development of collectivity has been inferred based on the low-energy level schemes of the even-even Fe and Cr isotopes and attributed to deformation arising primarily from the influence of the νg9/2 intruder orbital. The level schemes of the odd-A Co and Fe isotopes, as well as the odd-odd Co and Mn isotopes, are also influenced by the g9/2 orbital and suggest prolate deformation. However, scarce information is available regarding the neutron-rich odd-A Cr isotopes.
Purpose: Determine low-energy level schemes of the neutron-rich Cr isotopes approaching N = 40 and investigate the influence of the νg9/2 orbital. Method: Neutron-rich V isotopes were produced at the NSCL through projectile fragmentation. The β decay of the V isotopes into Cr isotopes was studied, and the observed β-delayed γ rays were used to determine the low-energy level schemes of the neutron-rich Cr isotopes. Results: A greatly expanded level scheme is constructed for Cr61, which has an increased low-energy level density relative to isotopic 55,57,59Cr. Excited states are discovered in Cr63 for the first time. Conclusion: The distinct difference between the low-energy level scheme of Cr61 and the lighter neutron-rich odd-A Cr isotopes is inferred to be due to the influence of the νg9/2 intruder orbital and suggests the possibility of low-energy positive-parity states in Cr61, leading to the conclusion that a significant change in deformation and orbital occupancies has taken place when N exceeds 36.- Publication:
-
Physical Review C
- Pub Date:
- March 2014
- DOI:
- 10.1103/PhysRevC.89.034317
- Bibcode:
- 2014PhRvC..89c4317S
- Keywords:
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- 23.40.-s;
- 21.10.-k;
- 27.50.+e;
- Beta decay;
- double beta decay;
- electron and muon capture;
- Properties of nuclei;
- nuclear energy levels;
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- =A<
- =89