prompt collective oscillations with exotic beamscolo/spes/barlini.pdf · thspes workshop, milano, 9...
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SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
Prompt collective oscillations with exotic beams
Letter of intent for the SPES-ALPI facility
S. Barlini from INFN-Fi and University of Florence
Subscribers from:
INFN (Fi, Mi, LNL, Bo, Ct, LNS)
LPC, Caen, France
Daresbury, UK;
NIPNE, Romania;
Nevsheir University, Turkey;
IFJ PAN Krakòw, Jagellonian Univ., Warsaw Univ., Poland;
Ohio University, US
The physic case: the Dynamical Dipole Resonance (DDR)
γ
It is a collective dipole oscillation along the symmetry axis occurring at the
beginning of the interaction between charge asymmetric heavy ions
CN
Possible emission
of DDR from a not
equilibrated
source
Possible emission
of GDR in the CN-
decay
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
V.Baran et al. PRL 87,2001 and PRC79,2009
M.DiToro et al. EPJ A13 2002
𝐷0 =𝑟0(𝐴𝑝
1/3+ 𝐴𝑡
1/3)
𝐴𝑍𝑝𝑍𝑡
𝑁𝑡𝑍𝑡
−𝑁𝑝
𝑍𝑝
Main features of DDR emission:
• The DDR yield grows as a function of the charge-asymmetry of
the two reaction partners. Usually, the DDR is studied as a
function of the initial dipole moment (D0) of the system,
defined as
• The gamma energy of DDR is shifted to lower values
(around 10 MeV) with respect to GDR emission, as a
consequence of the larger deformation of the system
N/Z
dependence
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
• DDR occurs in the range 6-12AMeV:
below 6AMeV the acceleration felt by the charge
distribution is too small
beyond 12AMeV quenched oscillations and high pre-
equilibrium particle emission
Energy range
6-12AMeV
• DDR produces gamma’s with angular distribution peaked
perpendicularly to the interaction axis of the two nuclei
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
Some experimental results:
The “standard” technique to disentangle the DDR emission is the comparison
between two reactions (one charge symmetric system with small D0 and one
charge asymmetric system with big D0) producing the same CN.
A.Corsi et al., Phys.Lett.B 679 (2009), 197
B.Martin et al., Phys.Lett.B 664 (2008), 47
D.pierroutsakou, Phys.Rev. C80 (2009), 024612
Reaction Elab
(AMeV)
E*
(MeV)
D0
(fm)
32S+100Mo 6.125 117 18.2
36S+96Mo 5.95 117 1.7
32S+100Mo 9.3 174 18.2
36S+96Mo 8.9 174 1.7
36Ar+96Zr 16 285±9 20.6
40Ar+92Zr 15.1 284±9 4.0
Reaction Elab
(AMeV)
E*
(MeV)
D0
(fm)
64Ni+68Zn 4.7 100 1.2
16O+116Sn 8.1 94±3 8.6
64Ni+68Zn 7.8 200 1.2
16O+116Sn 15 165±7 8.6
It is difficult to extract correctly
the DDR emission, but …
Some examples from LNL and LNS recent experiments
…but in any case:
• pre-equilibrium particles emission should be taken into account
(determination of E*) (importance of LCP detection)
Proton
Alpha
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
Moving source technique to separate the evaporation
and pre-equilibrium contribution
• neutrons should be taken into account (from model and
systematics)
• Importance of DDR angular distribution
…but in any case:
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
difference
between 36,40Ar+96,92Zr
𝑀𝛾 = 𝑀0 1 + 𝑎2𝑃2(𝑐𝑜𝑠𝜗)
a2=-1
a2=-1 emission from a
dipole oscillating along
the beam axis
40Ar+92Zr 36Ar+96Zr
• Comparison of DDR gamma multiplicity with BNV model
as a function of Ebeam: the dynamic of the interaction
between beam and target influences the DDR strength
…but in any case:
EoS
Different ingredients in model
calculation can be tested:
• Asy-stiff or Asy-soft
• nn cross section
• Etc…
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
N/Z dependence
Energy range 6-12 AMeV DDR emission
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
The proposed experiment
Reaction N/Z CN D0
(fm)
133Cs+48Ca 1.42 – 1.40 181Re 1.2
142Cs+40Ca 1.58 - 1.00 182Re 36
141Cs+40Ca 1.56 – 1.00 181Re 36
Stable beam
SPES beam
Of course also the
Sn region is
interesting
Reaction N/Z CN D0
(fm)
124Sn+56Fe 1.48 – 1.15 180Os 25
90Kr+90Zr 1.50 - 1.25 180Os 21.5
Possible DDR dependence on the
mass asymmetry between
projectile and target (difference
in the dynamics of interaction)
Reaction N/Z CN
124Sn+58Ni 1.48 – 1.07 182Pt
124Sn+64Ni 1.48 - 1.29 182Pt
132Sn+58Ni 1.64 – 1.07 190Pt
Reaction N/Z CN
124Sn+48Ca 1.48 - 1.40 172Yb
132Sn+40Ca 1.64 – 1.00 172Yb
142Cs : 2* 108pps
141Cs : 2* 107 pps
90Kr : 8.7 107pps
132Sn : 3.1 107 pps
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
The experimental apparatus
Evaporation Residue
(and Fission Fragments)
Detection
LCP for pre-
equilibrium estimation Gamma detector
• PPAC
• Phoswich
detectors
• Rco detector
• Mass
spectrometer
• ….
• GARFIELD
• FAZIA
• FARCOS
• TRACE
• ...
• HECTOR
• SERPE
• MEDEA
• PARIS
• …
It is important to detect at the same time the ER, LCP and gamma
rays (with ER-gamma and ER-LCP coincidences). A strong
collaboration among the different experimental groups interested in
this type of experiments should start in order to find what is the best
and most feasible solution that can be implemented.
…and some detectors for neutrons?
Not in
vacuum!
133Cs + 48Ca @10 AMeV: a GEMINI simulation
Z
Theta
Z Z
Counts
Counts
Only ER mechanism
ER FF
ER
FF
Max θER
Reverse
kinematics!
Z
ER
FF
Ela
b
Z
Theta
ER
FF
Z1
Z2
Z1,Z2 are the largest fragments
θZ1
θZ2
Z1,Z2 are well correlated as
emission angle
FF
ER
Asymmetric
Fission
133Cs + 48Ca @10 AMeV: a GEMINI simulation
ToF (ns)
ToF (ns) ToF (ns)
A
A A Theta < 30° Theta < 10°
2m of ToF 2m of ToF
2m of ToF
Simple ToF gate
Z
Elab
ToF (ns)
2m of ToF
133Cs + 48Ca @10 AMeV: a GEMINI simulation
beam
• Narrow angular distribution of ER (θmax<5°)
• Grazing angle of the reaction around 6°
• Contributions from the Fission process to be evaluated (33%
using standard GEMINI parameters)
• Possibility to disentangle Evaporation process from fission
process using ToF (with 2 m of path) at angles θ<10°
We need to work together to find the
best experimental solution!
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013
133Cs + 48Ca @10 AMeV: a GEMINI simulation
G.Casinia, S. Barlinia, M. Binia, M. Brunob, M. Cinauseroe, M. D'Agostinob, D. Fabrise,
N. Gellia, F. Gramegnae, T. Marchie, L. Morellib, A. Nanninia,A. Olmia, S. Valdrea, G.
Pasqualia, S. Piantellia, G. Poggia, R. Albag, C. Maiolinog, D. Santonocitog, G. Pretee,
A. Braccoc, F. Camerac, A. Corsi c, O. Wielandc, M. Ciemalad, B. Fornald, M. Kmiecikd,
A. Majd, K. Mazurekd, B. Wasilewskad, C.Borceai , M. Parloglp,i, M. Degerlierf , T.
Kozikju, A. Kordyaszwa, P. Kuligju, Z. Sosinju, A. Wielochju, T. Twarogju, D. Sierpowskiju,
M. Kajetanowiczju, J. Lukasikd,K. Korcyld,B. Klossi, S. Kowalskisi, A. Grzeszczuksi,W.
Zippersi, M. Chartierh, R. Lemmonh, Z. Basrakz, M. Milinz, N. Soicz, S. Szilnerz, A.
Voinovoh, M.Colonnag, M.Di Torog, C.Rizzog, V.Barani
a INFN, Sezione di Firenze and Dipartimento di Fisica dell'Università, Firenze, Italy b INFN, Sezione di Bologna and Dipartimento di Fisica dell'Università, Bologna, Italy c INFN, Sezione di Milano and Dipartimento di Fisica dell'Università, Milano, Italy d H. Niewodniczanski Institute of Nuclear Physics PAN, Krakow, Poland e INFN, Laboratori Nazionali di Legnaro, Italy f Nevsehir University of Science and Art Faculty Physics Department, Nevsheir, Turkey g INFN, Laboratori Nazionali del Sud , Catania, Italy h Daresbury Laboratory, Cheshire, United Kingdom i NIPNE-HH and Bucharest University, Romania wa University of Warsaw, Poland ju Jagellonian University, Krakow, Poland si Silesian University, Katowice, Poland oh Ohio University , US lp LPC, Caen, France z R. Boskovic Institute, Zagreb, Croatia
A.Corsi et al., Phys.Lett.B 679 (2009), 197
D.pierroutsakou, Phys.Rev. C80 (2009), 024612
Different methods to extract the DDR emission
40Ar+92Zr 36Ar+96Zr
difference
DDR yield obtained as a
comparison with statistical code.
DDR yield obtained as a difference
between the two charge-
symmetric reactions.
SPES WORKSHOP, Milano, 9 th- 10th Dicember 2013