Neutron Shell Breaking in Neutron-Rich Neon Isotopes

When?

Tuesday 25 January 2011, 14:00

Where?

30 BB 03 Physics Seminar Room

Open to:

Staff, Students

Speaker:

Dr Simon Brown, University of Surrey

In the region of the of the sd shell, it is known that the magic number N = 20 does not exist far from stability [1] and recent experiments have indicated the existence of a new shell closure at N = 16 in neutron-rich nuclei [2,3]. This shell migration has been attributed in part to the monopole shift of the neutron d3/2 energy, which lies between the s1/2 orbital and the pf shell [4]. 

An excellent way to probe this evolution is to measure the strength of single-particle states in isotopes where the relevant orbitals are empty apart from the probe neutron. This removes many effects of the interactions between neutrons.  In the present work, this is pursued by measuring proton angular distributions in (d,p) transfer reactions producing states in 27Ne.  A 9.8A MeV 26Ne beam produced by the SPIRAL facility at GANIL bombarded a 1 mgcm?2 CD2 target.  Measurements of the protons, gamma-rays and the heavy recoil particles were utilised to identify states in 27Ne whether they were bound, unbound or bound but isomeric.  The results are compared to shell model calculations and their structural implications are discussed. 

References:

[1] C. Detraz et al, Physics Review C 19, 164 (1979).

[2] M. Stanoiu et al, Physics Review C 69, 034312 (2004).

[3] A. Obertelli et al, Physics Review C 71, 024304 (2005).

[4] T. Otsuka et al, Phys. Rev. Lett. 105 032501 (2010).