High-Resolution In-Beam Spectroscopy of 131 Sn 81 Precise location of the neutron single-particle states & First measurement of neutron transfer on an isomer Anissa Bey University of Tennessee, Knoxville JIHIR, ORNL XXXIII Mazurian Lakes Conference on Physics - Frontier in Nuclear Physics Piaski, Poland, 1-7 September, 2013 Piaski|03/09/2013
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High-Resolution In-Beam Spectroscopy of 131Sn81
Precise location of the neutron single-particle states &
First measurement of neutron transfer on an isomer
Anissa Bey University of Tennessee, Knoxville
JIHIR, ORNL
XXXIII Mazurian Lakes Conference on Physics - Frontier in Nuclear Physics Piaski, Poland, 1-7 September, 2013
Piaski|03/09/2013
R-process in the vicinity of 132Sn
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 2/13
from J.J. Cowan et al., Physics Today 47 (2004)
Z=50
N=82
Limit of laboratory
experiments
r-process path
R-process
Nucleosynthesis mechanism responsible for
production of approx. half of heavy elements
beyond iron (A=70) peak
Interplay between rapid neutron captures (n,),
photo-dissociation (,n), and -decay
Crucial inputs
Masses, half-lives, and -n ratios
R-process in the vicinity of 132Sn
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 2/13
from J.J. Cowan et al., Physics Today 47 (2004)
Z=50
N=82
Limit of laboratory
experiments
r-process path
R-process
Nucleosynthesis mechanism responsible for
production of approx. half of heavy elements
beyond iron (A=70) peak
Interplay between rapid neutron captures (n,),
photo-dissociation (,n), and -decay
Crucial inputs
Masses, half-lives, and -n ratios
Late times, freeze-out stage, (n,) captures on
some “seed” nuclei can be decisive in defining
the final isotopic abundance pattern
Case with 130Sn
However!
R. Surman et al., PRC 64, 035801 (2001)
& PRC 79, 045809 (2009)
Freeze-out direct (n,) captures on 130Sn
N=82
Z=50 130Sn
3.72 m
131Sn
-56 s
132Sn
39.7 s
130In
0.29 s
131In
0.28 s
130Cd
162 ms
131Cd 132Cd
(n,)
-
(,n)
Adapted from:
R. Surman et al., PRC 79, 045809 (2009) ------------
J. Beun et al., JPG-NPP 36, 025201 (2009)
At R-process late times
Path nucleus 130Cd is highly populated
Significant amount of material is collected in 130Sn
Flow of material along Z=50 is sensitive to DC(n,) on 130Sn
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 3/13
Isotopic abundance sensitivity to (n,) captures on 130Sn
Abundance changes under increase of 130Sn(n,)131Sn rate by x100
12% overall on average
34% around A~195
191% near A~131
J. Beun et al., JPG-NPP 36 (2009)
130Sn Rate x 10 132Sn Rate x 10
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 4/13
DC(n,) sensitivities
FRDM
RMFT
HFB
Mass number A
Cro
ss s
ecti
on
[b
arn
]
(n,) cross-sections at 30 keV
In Sn isotopes, DC(n,) dominated by
captures to p-shell orbitals (3p1/2,3p3/2)
Largest dependencies of DC(n,)
on spin-parities J & energies Ex of
given individual shell model states
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 5/13
T. Rauscher et al., PRC 57, 4 (1998)
2h-1p excitations or single-particle states in 131Sn81 ?
130Sn(d,p)131Sn - R.L. Kozub et al.
Population of 4 lowest shell model states
S.F.s support a single-particle nature
131Sn Spectroscopic Factors (S.F.s)
DWBA calculations ( 30% uncertainty)
Neutron-rich beams transfer studies at HRIBF - ORNL
0.7
0.7 1.0
0.75
R.L. Kozub et al., PRL 109 (2012)
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 6/13
2h-1p excitations or single-particle states in 131Sn81 ?
130Sn(d,p)131Sn - R.L. Kozub et al.
Population of 4 lowest shell model states
S.F.s support a single-particle nature
Limited resolution; no GS population
Particle (d/d) insensitive to spin
(d,p) not well-matched to populate higher -----
----spin shell model states (1h9/2, 1i13/2)
131Sn Spectroscopic Factors (S.F.s)
DWBA calculations ( 30% uncertainty)
Neutron-rich beams transfer studies at HRIBF - ORNL
0.7
0.7 1.0
0.75
R.L. Kozub et al., PRL 109 (2012)
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 6/13
2h-1p excitations or single-particle states in 131Sn81 ?
130Sn(d,p)131Sn - R.L. Kozub et al.
Population of 4 lowest shell model states
S.F.s support a single-particle nature
Limited resolution; no GS population
Particle (d/d) insensitive to spin
(d,p) not well-matched to populate higher -----
----spin shell model states (1h9/2, 1i13/2)
131Sn Spectroscopic Factors (S.F.s)
DWBA calculations ( 30% uncertainty)
130Sn(9Be,8Be-) & (13C,12C-) - This work
In-beam -ray spectroscopy
precise energy location
infer spin from angular correlations
Neutron-rich beams transfer studies at HRIBF - ORNL
0.7
0.7 1.0
0.75
R.L. Kozub et al., PRL 109 (2012) 2 targets (13C, |1p1/2) and (9Be, |1p3/2)
different transfer matching conditions
probe spin selectivity
A. Bey High-Resolution In-Beam Spectroscopy of 131Sn81 Piaski|03/09/2013 6/13
High-resolution heavy-ion transfer experiments at HRIBF