Recent results from INDRA Abdou Chbihi GANIL For the ......From fission to multifragmentation IWM-EC, Catane May 2014 A. Chbih i 13 VrelRatio62 Entries 17697 Mean 4.037 RMS 1.829 χ2

IWM-EC, Catane May 2014

A. Chbihi 1

Recent results from INDRA

Abdou Chbihi GANIL

For the INDRA collaboration

Recent results from INDRA

•  Introduction to the INDRA talks •  Study of the reaction mechanisms from fission to

multifragmentation •  Symmetry energy : INDRA-VAMOS experiments •  conclusions


A. Chbihi 2

Time evolution of central collisions at intermediate energies


A. Chbihi 3

Pre-equilibrium, stopping, compression Flow, expansion Fragmentation Secondary

decays

M. Colonna, A. Ono and J. Rizzo PRC82, 054613 (2010)

Explore the EOS under laboratory controlled conditions

HIC is Femtonovae which mimic Supernovae

Key words : stopping, collective flow, clusterization

ECT* 2014 : Simulating the Supernova Neutrinosphere with Heavy Ion Collisions



A. Chbihi 4


decays


Nuclear Stopping : O. Lopez talk •  Minimum of stopping around the Fermi energy •  Full stopping is not achieved •  Transparency due to in-medium effect •  Determination of experimental mean free path λNN



A. Chbihi 5


decays


Radial flow: J. D. Frankland talk •  Influence of radial collective flow on multif partitions in central Xe+Sn & Ta+Zn



A. Chbihi 6


decays


isospin dependence of nuclear level density parameter : G. Ademard talk

•  Experiment coupling INDRA + Vamos, •  Ar+Ni @ E/A ≈13 MeV à92-108Pd excited at E*/A ≈ 3 MeV

Internal excitation energy of the fragments : E*/A ≈ 3 MeV

outline

•  Introduction to the INDRA talks •  Study of reaction mechanisms from fission to

multifragmentation •  Symmetry energy : INDRA-VAMOS experiments •  conclusions


A. Chbihi 7

From fission to multifragmentation

E/A=8 MeV

E/A=29 MeV

•  Survey of heavy nuclei up to Z≥80 (77% tot)

•  Suggests fusion of the colliding nuclei but massive transfer is not excluded

•  High LCP multiplicities : dissip colli •  minima at Z = 10


8 A. Chbihi A.C. et al., JP: Conf. Ser. 420, 012099 (2013).

Study of the evolution of reaction mechanism occurring in HIC from low to IE •  Tool : 4π detector •  What can we Learn ?

ü  Transition from low energy (DIC, fusion-fission) to IE (multifragmentation)

ü  Bring insight for search for SHE ü  Stringent constraint on statistical &

dynamical models

Xe+Sn @ E/A=8-29 MeV, CC

Fusion cross section

(A.MeV)BeamE0 5 10 15 20 25 30 35 40

(m

b)

fus

!

0

200

400

600

800

1000

1200

1400

1600

Fus!

Maximum around 18-20 MeV/A σfus : 1.2 b


9 A. Chbihi


Einc /A (MeV)

σfu

s (m

b)


10 A. Chbihi


fission

3-frag prob

abili

ty

Beam energy (MeV/A)

Decomposition on 2, 3, 4+ fragments (Z>10)

Exit channel probability vs beam energy



A. Chbihi 11

D. Gruyer et al., EPJ Web of Conferences 62, 07006+ (2013) and submitted to Physical Review Letters (arXiv:1309.7779)

Excitation energy (MeV/A)

Life

tim

e (fm

/c)

Beam energy (MeV/A)

Fission time deduced from Coulomb trajectory calculations

2nd fission occurs faster and faster as E* increases

Undistinguishable from simultaneous 3-frag breakup above E*/A ≈4 MeV

Mean life time of 2nd fission

See poster and short talk of D. Gruyer… 3-frag exit channel : identify fission sequence by comparison with TKE systematics (Viola)

Energy spectra of proton alpha in coincidence with 2-, -3 and 4-frag 129Xe + (nat)Sn @ E/A=15 MeV

•  Maxwellian shape •  Same slop for 2, 3, and 4 fragments à same temperature àsame origin •  overproduction at Ecm <10, increasing with Mfrag à secondary decay


12 A. Chbihi

proton alpha

Ecm/A (MeV) Ecm/A (MeV)

dσ/d

Ecm

N

orm

aliz

ed dσ

/dE

cm



A. Chbihi 13

VrelRatio62Entries 17697Mean 4.037RMS 1.829

/ ndf 2χ 12.79 / 29a 2.6± 3 b 0.00535± 0.02423 c 0.0106± 0.3338 N 0.928± 4.543 Cb 0.031± 2.468 T 0.0685± 0.4797

Vrel(cm/ns)0 1 2 3 4 5 6 7 8

1+R

(Vre

l)

0.20.40.60.8

11.21.41.61.8

2VrelRatio62

Entries 17697Mean 4.037RMS 1.829

/ ndf 2χ 12.79 / 29a 2.6± 3 b 0.00535± 0.02423 c 0.0106± 0.3338 N 0.928± 4.543 Cb 0.031± 2.468 T 0.0685± 0.4797

Correlation function frag-LCP

VrelDiff62Entries -299656Mean 341.1RMS 338.8

Vrel(cm/ns)0 1 2 3 4 5 6 7 8

diffe

renc

e fu

nctio

n

-600-400-200

0200400600800

1000 VrelDiff62Entries -299656Mean 341.1RMS 338.8

Difference function frag-LCP

hsignalEntries 100Mean 3.474RMS 0.6502

/ ndf 2χ 7.4 / 25N 126.1± 1281 B(MeV) 0.55± 13.57 T(MeV) 0.631± 5.269

Vrel (cm/ns)1 2 3 4 5 6

0200400600800

100012001400


/ ndf 2χ 7.4 / 25N 126.1± 1281 B(MeV) 0.55± 13.57 T(MeV) 0.631± 5.269

deduced velocity spectra

Z (= 62) - α

Xe+Sn @ E/A=12 MeV Secondary decay contribution using fission frag-LCP correlation function

Mtot

Msec

Secondary and total multiplicity vs beam energy

Vrel(cm/ns)

1+R

(Vre

l) N

C -

NN

C

α

Cou

nt(V

rel)



A. Chbihi 14

Secondary decay contribution for fission /multifragmentation fragments

Mtot

Msec

fission

multifrag

S. Hudan et al., PRC67, 064613 (2003)

Decrease in Msec for Ebeam/A > 39 MeV reflects saturation on excitation energy

VrelRatio62Entries 17697Mean 4.037RMS 1.829

/ ndf 2χ 12.79 / 29a 2.6± 3 b 0.00535± 0.02423 c 0.0106± 0.3338 N 0.928± 4.543 Cb 0.031± 2.468 T 0.0685± 0.4797

Vrel(cm/ns)0 1 2 3 4 5 6 7 8

1+R

(Vre

l)

0.20.40.60.8

11.21.41.61.8

2VrelRatio62

Entries 17697Mean 4.037RMS 1.829

/ ndf 2χ 12.79 / 29a 2.6± 3 b 0.00535± 0.02423 c 0.0106± 0.3338 N 0.928± 4.543 Cb 0.031± 2.468 T 0.0685± 0.4797

Correlation function frag-LCP

VrelDiff62Entries -299656Mean 341.1RMS 338.8

Vrel(cm/ns)0 1 2 3 4 5 6 7 8

diffe

renc

e fu

nctio

n

-600-400-200

0200400600800

1000 VrelDiff62Entries -299656Mean 341.1RMS 338.8

Difference function frag-LCP


/ ndf 2χ 7.4 / 25N 126.1± 1281 B(MeV) 0.55± 13.57 T(MeV) 0.631± 5.269

Vrel (cm/ns)1 2 3 4 5 6

0200400600800

100012001400


/ ndf 2χ 7.4 / 25N 126.1± 1281 B(MeV) 0.55± 13.57 T(MeV) 0.631± 5.269

deduced velocity spectra

Z (= 62) - α

Xe+Sn @ E/A=12 MeV

Vrel(cm/ns)

1+R

(Vre

l) N

C -

NN

C

α

Cou

nt(V

rel)

outline

•  Introduction to the INDRA talks •  From fission to multifragmentation •  Symmetry energy : INDRA-VAMOS experiments •  conclusions


A. Chbihi 15

Exploring the symmetry energy with HIC

•  information on the EOS: need to study fragments at

freeze-out, BEFORE secondary decays : •  But remember: observables measured after

secondary decay (need back-tracing) –  isotopic distributions, –  Isoscaling


A. Chbihi 16

€

E(ρ,δ) /A = E(ρ,δ = 0) /A + S(ρ) ⋅ρn − ρp

ρn + ρp

&

' ( (

)

* + +

2


A. Chbihi 17

Accessing the symmetry energy

From isotopic distribution…

AMD simulations: 48Ca+48Ca and 40Ca+40Ca, E/A=35 MeV and b > 6 fm Primary fragment distributions

A. Ono et al., Phys. Rev. C70, 041604(R) (2004)

− lnY (N,Z ) = ξ (Z )N +η(Z )+ζ (Z ) (N − Z )2

N + Z

ζ (Z )∝1/σ ∝Csym (Z ) /T

Y2 (N ,Z )Y1(N ,Z )

=C exp(αN +βZ)α = Δµn /T,β = Δµp /Tα4Δ =Csym (Z) /T

Δ = ( Z<A1>)2 − ( Z

<A2>)2

isocaling parameter

From isoscaling…

-lnY

(N,Z

)

Aprimary


A. Chbihi 18

Effects of secondary decays

•  After decay : Cannot distinguish between the two interactions (soft/stiff)

•  Secondary decays need to be taken into account for comparison to experimental data

•  Statistical model

•  Or/and : experimentally provide the primary distributions

primary GEMINI : secondary

isoscaling

Isotopic dist ζ (Z)

α4Δ

Zprimary ZPLF


A. Chbihi 19

INDRA

Q1 Q2

Dipole

beam

detection


A. Chbihi 20

INDRA

Q1 Q2

Dipole

beam

detection

VAMOS PLF (E503) or residues (E494s) High Isotopic Resolution

INDRA in coincidence LCP /IMF event characterization (b, excitation energy)


A. Chbihi 21

Experiments coupling INDRA-VAMOS Symmetry energy experiments •  40Ca + 40Ca @ E/A = 35 MeV •  40Ca + 48Ca @ E/A = 35 MeV isospin diffusion •  48Ca + 40Ca @ E/A = 35 MeV isospin diffusion •  48Ca + 48Ca @ E/A = 35 MeV For Bρ (Tm)= 2.2 , 2.12 , 1.957 , 1.80 , 1.656 , 1.523 ,

1.401 , 1.289 , 1.186 , 1.091 , 1.004 , 0.923 , 0.849 , 0.782 , 0.719 , 0.661

VAMOS Spectrometer

INDRA, 4π detector

Isotopic distributions of PLF


A. Chbihi 22

•  Broad APLF distributions (more than 13 isotopes) •  Sensitive to the n-richness of the system •  N/Z up to 1.58 (11% N/Z 48Ca) very exotic

Reconstruction of primary fragments


A. Chbihi 23

ecos-1 -0.5 0 0.5 1

Y(ar

b.un

it)

1

10

210

310

v//(cm/ns)-10 -5 0 5

(cm

/ns)

perp

v -5

0

5

10

1

10b)

ecos-1 -0.5 0 0.5 1

Y(ar

b.un

it)

1

10

210

310no constraint

>0CMvVrel>vI

rel>0, vCMv

v//(cm/ns)-10 -5 0 5

(cm

/ns)

perp

v -5

0

5

10

1

10a)

proton alpha ZPLF = 20

Corrected for the reaction plan

Apr −Mn = APLF + Aii=1

MLCP

∑

Zpr = ZPLF + Zii=1

MLCP

∑V//

cm > 0For


A. Chbihi 24

Can be used as an observable Evaluation of the effect of neutron emission on the width : AMD+GEMINI It will be used as correction to the data.

reconstruction of primary fragments Apr −Mn = APLF + Ai

i=1

MLCP

∑•  Up to 20 isotopes •  Average value and σ

increases with Zpr •  Small differences for

light Zpr •  Strong dependence on

the n-richness of the system for heavy fragments

•  small dependence on the n-richness of the target

Apr −Mn

Staggering effect for PLF and primary frag


A. Chbihi 25

The staggering is determined by secondary evaporative stage No sensitivity to dynamics.


A. Chbihi 26

Neutron influence on the width of isotopic distributions

Apr −Mn = APLF + Aii=1

MLCP

∑

Comparison of the width of iso-dist AMD (hot) and AMD-N(GEMINI)

4040 4848

wid

th

Differences in the width between AMD and AMD-N as uncertainties when applied to data

Symmetry energy term vs the excitation energy comparison with AMD-N(Gemini), b>6 fm


A. Chbihi 27

σ =1N

(exp− calc)2i∑

From width of isotopic dist

Temperature obtained from slope of p-spectra 4-6 MeV Values of Csym around 30 MeV Consistent with the values of saturation density The method is validated and should be applied to more dissipative collisions


A. Chbihi 28

0 10 20 30 40 50 60

5

10

15

20

25

30

35

40

45

50

-310

-210

-110

1

10

210

310

N=20

N=28

N=50

Z=20

Z=28

0 10 20 30 40 50 60

5

10

15

20

25

30

35

40

45

50

-310

-210

-110

1

10

210

310

N=20

N=28

N=50

Z=20

Z=28

Production of exotic nuclei beyond the drip lines

48Ca+48Ca PLF

primary

Spectroscopy of 29Si


A. Chbihi 29

29Si(p,γ)30P

29Si*

32P->p+31Si* ->n+ 30Si* ->29Si*+n

•  Experimental reconstruction (correlation techniques) •  Study excited states of exotic

nuclei •  Study cluster states in nuclei (in progress)


A. Chbihi 30

•  Experimental study of Xe+Sn @ E/A=8-29 MeV •  Determination of fusion cross section, max cx = 1.2 b, around E/

A=18-20 MeV •  Life time of the 2nd fission was determined : simultaneous break

up above E*/A = 4 MeV. •  Estimation of secondary decay for proton and alpha particle

shows continuous evolution from fission to multifragmentation


A. Chbihi 31

Summary and Conclusions

•  Exploration of Esym(ρ) with HI-Collisions •  Observable : isotopic distribution of frag & isoscaling •  Accessing the symmetry energy

–  Take into account the secondary effects –  Primary experimental isotopic distributions

•  Zprimay distributions were reconstructed experimentally •  Aprimary – neutrons distributions reconstructed exp. but need to take into account

the effect of neutron emission on the Apr – neutrons distributions •  Staggering effects are washed with this reconstruction

•  Both methods (isoscaling and isotopic distributions) can be used to extract the symmetry energy term if applied for primary quantities

•  Esym was extracted for peripheral collisions, the values obtained are consistent with the value at normal density :

•  work is in progress for central collisions


A. Chbihi 32

Summary and Conclusions

perspectives


A. Chbihi 33

perspectives


A. Chbihi 34


A. Chbihi 35

A. Chbihi, G. Verde, E. Bonnet, J.D. Frankland, M. Boisjoli, P. Marini, J. Moisan, B. Sorgunlu, F. Rejmund, M. Rejmund, J.P. Wieleczko,

Sarmishtha Bhattacharya, P. Napolitani GANIL, CEA, IN2P3‑CNRS, FRANCE

INFN, Catania, ITALY B. Borderie, E. Galichet, N. Le Neindre, M.F. Rivet

IPN Orsay, IN2P3‑CNRS, FRANCE R. Dayras, L. Nalpas, C. Volant

DAPNIA/SPhN, CEA Saclay, FRANCE D. Guinet, P. Lautesse

Institut de Physique Nucléaire, IN2P3‑CNRS et Université, Caen Cedex, FRANCE R. Bougault, O. Lopez, B. Tamain, E. Vient

LPC. IN2P3‑CNRS. ENSICAEN et Université, Caen Cedex, FRANCE A. Ono

Department of Physics, Tohoku University, Sendai, JAPAN R. Roy

Université de Laval, Quebec, CANADA W. Trautmann, J. Lukasik

GSI, D-64291 Darmstadt, GERMANY E. Rosato, M. Vigilante

Dipartimento di Scienze Fisiche, Un. Federico II, Napoli, ITALY M. Bruno, M. D’Agostino, E. Geraci, G. Vannini

INFN and Dipartimento di Fisica, Bologna ITALY L. Bardelli, G. Casini, A. Olmi, S. Piantelli, G. Poggi

INFN and Dipartimento di Fisica, Firenze,ITALY F. Gramegna, G. Montagnoli

INFN, Laboratori Nazionali di Legnaro, ITALY U. Abbondanno

INFN, Trieste, ITALY M. Parlog, G. Tabacaru

National Institute for Physics and Nuclear Engineering, Bucarest‑Maguerele, ROMANIA Saila. Bhattacharya, G. Mukherjee

Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata, INDIA

Documents

Recent results from INDRA Abdou Chbihi GANIL For the ......From fission to multifragmentation IWM-EC, Catane May 2014 A. Chbih i 13 VrelRatio62 Entries 17697 Mean 4.037 RMS 1.829 χ2