Realistic Shell Model Interactions in Nuclei
Structure of Sb nuclei around
132
Sn as a
testing ground for realistic shell model
interactions
B. Szpak
,
B. Fornal
,
P. Bednarczyk, M. Ciemała,
N. Cieplicka,
M. Kmiecik,
W. Królas,
A. Maj
Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
S. Leoni
1,2
, S. Bottoni
1,2
, G. Benzoni
2
, A. Bracco
1,2
, F. Crespi
1,2
1 Università degli Studi di Milano, Via Celoria 16, 20133, Italy
2 INFN, sezione di Milano, Italy
K. Rusek
Heavy Ion Laboratory, University of Warsaw, Poland
R. Raabe
Instituut voor Kern-en Stralingsfysisca, KU Leuven, Belgium
S. Lunardi, D. Bazzacco, S. Lenzi, R. Menegazzo, D. Mengoni, C. Michelagnoli, F. Recchia, C.A. Ur
Department of Physics, University of Padova and INFN, Padova, Italy
G. de Angelis, D.R. Napoli, J. Valiente-Dobon,
INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy
G. de France, E. Clement, C. Michelagnoli
GANIL, Caen,
France
We
propose a
method for
gamma
-ray
spectroscopic studies of low-
lying structures in
nuclei lying close to the projectile nucleus.
The method relies on the triton transfer process induced by
radioactive beams on a
7
Li target.
Z
Z
+
1
for example:
1
3
3
S
n
+
7
L
i
1
3
4
S
b
+
α
+
2
n
We would like to propose a gamma spectroscopic studies of low-lying
structures in
127-134
Sb, by employing
cluster transfer
reactions induced
by the radioactive beams of
126-133
Sn on a
7
Li target.
The nuclei will be populated in a
7
Li(
A
Sn,α2n)
A+1
Sb process.
I will discuss:
1.
Physical motivation
2.
Current experimental information
3.
7
Li(
A
Sn,α2n)
A+1
Sb
reaction
4.
Advantages of the suggested method
The realistic shell model calculations ha
ve
opened a „new
chapter” in nuclear structure physics.
Parameter-free
calculations
around doubly-magic nuclides become possible.
No adjustment
of interaction is necessary to obtain the
excellent agreement
with
the experimental data.
The nuclides from the vicinity of
132
Sn and
208
Pb provide the best
data to test the experiment against theoretical predictions.
However the experimental information is very sparse.
L. Coraggio, A. Covello, A. Gargano, N. Itaco, PRC
80
, 021305(R) (2009)
L. Coraggio et. al. PRC
66
, 064311 (2002)
The situation results from the inaccessibility of the region in standard fusion-
evaporation or deep-inelastic reactions with stable projectiles and targets. What
little is known comes mainly from beta-decay studies or spectroscopic
investigations of fission products.
132
Sb
The nuclei of interest will be populated in a reaction:
7
Li(
A
Sn,α2n)
A
+1
Sb
Dasgupta
et. al
. PRC
66
, 041602(R) (2002)
There is a significant probability of a
7
Li beam
nucleus breaking up, with a triton being
captured while α particle is emitted. Reaction
offer access to states at relatively high angular
momentum.
Clark et. al. [Cla] investigated the population of nuclei
formed in reactions involving
7
Li beams on targets of
160
Gd
and
184
W.
•
cross-section for the (
7
Li,α2n) process at beam
energies of a few MeV above Coulomb barrier is of
order of
100
mb
•
exceeds by 1-2 orders of magnitude the predictions
of a standard fusion-evaporation model
•
can be explained by using the Wilczynski binary
transfer model + standard evaporation model.
[Cla] R. M. Clark et. al. PRC
72
, 054605
(2005)
Incomplete fusion
Fusion-evaporation
The (
7
Li,α2n) incomplete fusion reactions
have been used to populate high-spin
states in
121,123
Sb [Wat] and in
179
Hf [Mul].
[Wat] H. Watanabe et. al. PRC
79
, 024306
(2009)
[Mul] S. M. Mullins et. al. PRC
61
, 044315
(2000)
Recently, excited states in
123,125
Sb with
spins up to 23/2 have been studied
following the
122,124
Sn(
7
Li,α2n)
123,125
Sb
incomplete fusion reaction at beam
energy of 35, 37 MeV.
D. S. Judson et. al. PRC
76
, 054306
(2007)
125
Sb
1
3
3
Spectroscopy of n-rich
98-100
Sr nuclei with
7
Li(
98
Rb,axn) reaction at
≈
3MeV/u
Spokepersons: S. Leoni and B. Fornal
Collaboration: Univ. of Milan, IFJ PAN Kraków, SLCJ Warsaw, GANIL, LNL
Legnaro, Univ. of Padova, K.U.Leuven, Université Libre de Bruxelles, CSNSM
Orsay, Univ. of Köln, TU Darmstadt, TU Munchen, LPSC Grenoble, Argonne
Nat. Lab., IFIN-HH Bucharest, IRNE-BAS Sofia, ISOLDE CERN.
Cluster transfer reactions of radioactive
beams
98
Rb/
98
Sr on a
on a 1.5 mg/cm
2
thick
LiF target
[Bot]
.
Beam for 3 days.
E
beam
=
2.85 MeV/A
I=
2
x
10
4
pps
MINIBALL + T-REX setup
[Bot] S. Bottoni et. al. Acta Phys. Pol. 45 (2014)
t-transfer
α
-transfer
A
Sn beam
500-600 MeV
7
Li target
TRACE
- Tracking
Array for light charged
particle ejectiles
A
Sn
A+1
Sb
*
A+1
Sb
α
γ
-rays
AGATA
Recoil cone < 3
o
7
Li
Beam energy:
500-600 MeV
Target thickness:
1 mg/cm
2
We assume :
•
100
mb
for the (
7
Li,α2n) channel cross-section
•
50%
efficiency
of AGATA array triggered by
charged particle detector
This gives
:
•
Few thousands of gamma singles or double
gamma coincidence events per second
for
127-130
Sn
beam
•
For the reaction induced by the
131
Sn beam
leading to
132
Sb recorded gamma-gamma events will
be of the order of few hundreds per second
•
For a
133
Sn beam we get one order of magnitude
lower for the counting rate for
134
S
b
.
•
The very inverse kinematics guarantees that the product nuclei all travel
downstream in a very small recoil cone, thus Doppler correction do not require
recoil detection.
•
Reaction channel of interest will be uniquely associated with the emission
of an α particle.
•
The same reactions in their
7
Li(
A
Sn,p
x
n)
A
T
e
channel
will also populate with
appreciable yield the Te nuclei with A=129-136. The emitted protons may be
used as event tags.
Presented counting rate estimates give us confidence that
detailed gamma-ray spectroscopic studies of the low lying
structures in
127-132
Sb will be possible at SPES.
Bartłomiej Szpak and team from the Polish Academy of Sciences explore the structure of Sb nuclei around 132Sn to test realistic shell model interactions. They propose cluster transfer reactions and conduct calculations around 132Sn using a parameter-free approach. Limited experimental data is available due to the inaccessibility of the region, with insights mainly coming from beta-decay studies and spectroscopic investigations of fission products. The use of triton transfer process induced by radioactive beams on a 7Li target facilitates gamma-ray spectroscopic studies of low-lying structures in nuclei close to the projectile nucleus, offering a method to study states with high angular momentum.
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Presentation Transcript
Structure of Sb nuclei around132Sn as a testing ground for realistic shell model interactions Bart omiej Szpak Institute of Nuclear Physics, Polish Academy of Sciences, Krak w, Poland B. Szpak, B. Fornal, P. Bednarczyk, M. Ciema a, N. Cieplicka, M. Kmiecik, W. Kr las, A. Maj Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland S. Leoni1,2, S. Bottoni1,2, G. Benzoni2, A. Bracco1,2, F. Crespi1,2 1 Universit degli Studi di Milano, Via Celoria 16, 20133, Italy 2 INFN, sezione di Milano, Italy K. Rusek Heavy Ion Laboratory, University of Warsaw, Poland R. Raabe Instituut voor Kern-en Stralingsfysisca, KU Leuven, Belgium S. Lunardi, D. Bazzacco, S. Lenzi, R. Menegazzo, D. Mengoni, C. Michelagnoli, F. Recchia, C.A. Ur Department of Physics, University of Padova and INFN, Padova, Italy G. de Angelis, D.R. Napoli, J. Valiente-Dobon, INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy G. de France, E. Clement, C. Michelagnoli GANIL, Caen, France
Cluster transfer reactions We propose a method for gamma-ray spectroscopic studies of low- lying structures in nuclei lying close to the projectile nucleus. The method relies on the triton transfer process induced by radioactive beams on a7Li target. AX + 7Li A+3-xY+ +xn Z Z+1 for example: 134Sb 133Sn + 7Li 134Sb+ +2n 133Sn
Realistic shell model calculations around 132Sn The realistic shell model calculations have opened a new chapter in nuclear structure physics. Parameter-free calculations around doubly-magic nuclides become possible. No adjustment of interaction is necessary to obtain the excellent agreement with the experimental data. The nuclides from the vicinity of132Sn and208Pb provide the best data to test the experiment against theoretical predictions. However the experimental information is very sparse. L. Coraggio, A. Covello, A. Gargano, N. Itaco, PRC 80, 021305(R) (2009)
Available experimental information The situation results from the inaccessibility of the region in standard fusion- evaporation or deep-inelastic reactions with stable projectiles and targets. What little is known comes mainly from beta-decay studies or spectroscopic investigations of fission products. 132Sb L. Coraggio et. al. PRC 66, 064311 (2002)
Cluster transfer reactions The nuclei of interest will be populated in a reaction: 7Li(ASn, 2n)A+1Sb There is a significant probability of a7Li beam nucleus breaking up, with a triton being captured while particle is emitted. Reaction offer access to states at relatively high angular momentum. Dasgupta et. al. PRC 66, 041602(R) (2002) Clark et. al. [Cla] investigated formed in reactions involving7Li beams on targets of160Gd and184W. cross-section for the (7Li, 2n) process at beam energies of a few MeV above Coulomb barrier is of order of 100 mb exceeds by 1-2 orders of magnitude the predictions of a standard fusion-evaporation model can be explained by using the Wilczynski binary transfer model + standard evaporation model. [Cla] R. M. Clark et. al. PRC 72, 054605 (2005) the population of nuclei Fusion-evaporation Incomplete fusion
Cluster transfer reactions Recently, excited states in123,125Sb with spins up to 23/2 have been studied following the incomplete fusion reaction at beam energy of 35, 37 MeV. The (7Li, 2n) incomplete fusion reactions have been used to populate states in121,123Sb [Wat] and in179Hf [Mul]. high-spin 122,124Sn(7Li, 2n)123,125Sb [Wat] H. Watanabe et. al. PRC 79, 024306 (2009) [Mul] S. M. Mullins et. al. PRC 61, 044315 (2000) D. S. Judson et. al. PRC 76, 054306 (2007) 125Sb
Our REX-ISOLDE experiment (November 2012) Spectroscopy of n-rich 98-100Sr nuclei with 7Li(98Rb,axn) reaction at 3MeV/u Spokepersons: S. Leoni and B. Fornal 98Rb + 7Li 101-xSr+ +xn 98Sr99Sr100Sr 98 Rb 133 Collaboration: Univ. of Milan, IFJ PAN Krak w, SLCJ Warsaw, GANIL, LNL Legnaro, Univ. of Padova, K.U.Leuven, Universit Libre de Bruxelles, CSNSM Orsay, Univ. of K ln, TU Darmstadt, TU Munchen, LPSC Grenoble, Argonne Nat. Lab., IFIN-HH Bucharest, IRNE-BAS Sofia, ISOLDE CERN.
REX-ISOLDE experiment Cluster transfer reactions of radioactive beams 98Rb/98Sr on a on a 1.5 mg/cm2thick LiF target [Bot]. Beam for 3 days. Ebeam=2.85 MeV/A I=2x104pps MINIBALL + T-REX setup [Bot] S. Bottoni et. al. Acta Phys. Pol. 45 (2014) -transfer t-transfer
Experimental setup TRACE Array for light charged particle ejectiles - Tracking ASn beam 500-600 MeV A+1Sb ASn 7Li A+1Sb* -rays 7Li target AGATA
Details of an experiment Beam energy: Target thickness: 1 mg/cm2 We assume : 100 mb for the (7Li, 2n) channel cross-section 50% efficiency of AGATA array triggered by charged particle detector 500-600 MeV Element particles/s 127Sn 8.16E+08 128Sn 6.36E+08 129Sn 3.50E+08 130Sn This gives: 1.58E+08 131Sn 6.83E+07 Few thousands of gamma singles or double gamma coincidence events per second for 127-130Sn beam For the reaction induced by the leading to132Sb recorded gamma-gamma events will be of the order of few hundreds per second 132Sn 3.11E+07 133Sn 2.76E+06 131Sn beam For a133Sn beam we get one order of magnitude lower for the counting rate for134Sb.
Advantages of the proposed experiment downstream in a very small recoil cone, thus Doppler correction do not require recoil detection. The very inverse kinematics guarantees that the product nuclei all travel of an particle. Reaction channel of interest will be uniquely associated with the emission appreciable yield the Te nuclei with A=129-136. The emitted protons may be used as event tags. The same reactions in their7Li(ASn,pxn)ATe channel will also populate with Presented counting rate estimates give us confidence that detailed gamma-ray spectroscopic studies of the low lying structures in127-132Sb will be possible at SPES.
