Giant Dipole Resonance â tool for hot nuclei studies Giant Dipole ...

Giant Dipole Resonance 

– tool for hot nuclei 

studies 

Maria Kmiecik 

Instytut Fizyki Jądrowej PAN, Kraków 

International Workshop on Acceleration 

and Applications of Heavy Ions, 

Warszawa, 27.02 – 12.03.2011 

Maria Kmiecik 

International Workshop on Acceleration and Applications of Heavy Ions, Warszawa 2011

The properties of Giant Dipole Resonances 

GDR as a tool for excited nuclei studies 

The results of the measurements: 

 

 

 

GDR width as a function of spin and temperature 

of nucleus 

The exotic shapes investigation 

Isospin mixing 

Perspectives 

Maria Kmiecik 


Giant Nuclear Resonances 

Collective excitations of atomic nuclei 

consisting in oscillations of nucleons. 

Called giant resonances (giant vibrations) because 

of large cross sections, close to maximum allowed 

for all nucleons participating in excitation 

At the microscopic level giant resonances can 

be described in terms of correlated particle-hole 

excitations 

Maria Kmiecik 


Giant Nuclear Resonances 

Usually classified in terms of three characteristic quantum numbers: 

L, S, and T, where L - the orbital angular momentum, 

S - the (intrinsic) spin, 

T - the isospin carried by the resonance oscillation. 

∆L=0 

∆L=1 

∆L=2 

Maria Kmiecik 


Electric Giant Resonances 

Isoscalar 

Isovector 

Monopole 

1977 

1983 

Dipole 

1996 

1948 

Quadrupole 

1971 

1980 

Maria Kmiecik 


Giant Dipole Resonance 

The giant electric dipole isovector resonance – 

giant dipole resonance (GDR) is the oldest and best 

known of the nuclear giant resonances. 

Observed for the first time in 1947 and 1948 

by Baldwin and Klaiber in (γ,fission) and (γ,n) 

reactions 

Measured using photoabsorbtion 

reactions for different nuclei 

from 3 He to 238 U 

(Berman and Fultz 1975) 

Maria Kmiecik 


Ground state GDR 

σ(E γ ) 

Photoabsorbtion cross section – 

GDR strength 

function: 

Γ 

A 

E GDR 

Strength σ 0 =1 (S GDR ) 

(maximum corresponding to 100% of nucleons 

participating in oscillations 

calculated from Energy Weighted Sum Rule – 

giant vibration, large collectivity) 

A 

Energy – centroid (E GDR ): 

energy of oscillations ~ 1/R 

Width (Γ GDR ) 

Γ ~ -1/t 

Maria Kmiecik 


GDR lineshape – deformed nucleus 

superposition 

of two Lorentzian function 

σ ( E 

γ 

σ ( E 

k 

) = σ ( E 

γ 

) = 

1 

( E 

2 

γ 

γ 

) + σ ( E 

σ Γ 

− E 

2 

2 

0 k 

2 2 

k 

) 

E 

2 

γ 

γ 

+ Γ 

Hill-Wheeler parameterization 

E 

E 

k 

= E 

GDR 

GDR 

R 

R 

≈ 79A 

k 

1 

− 

3 

= E 

GDR 

), 

2 

k 

E 

⎡ 

exp⎢− 

⎣ 

2 

γ 

5 2πk 

⎤ 

β cos( γ + ) ⎥, 

4π 

3 ⎦ 

quadrupole deformation parameter β 

β = 

E 

4π 

E 

5 E 

0.5 

E 

2 

1 

2 

1 

−1 

+ 0.87 

Maria Kmiecik 


GDR in excited nuclei 

GDR can be built on excited state of nucleus - Brink hypothesis, , 1955 

Maria Kmiecik 


Fusion – evaporation reaction. 

Excerpt from the © Jerzy Grebosz movie „Mysterious World of Atomic Nuclei” 

Maria Kmiecik 


Decay of compound nucleus 

E * [MeV] 

p 

p 

90 

t 

t 

jądro złożone 

80 

σ(L) 

70 

n 

60 

GDR γ 

Statistical decay 

50 

n 

α 

T ∝ E 

* − E yrast 

40 

n GDR γ 

n 

30 

n 

20 

E yrast 

10 

E yrast 

+ B n 

0 

0 10 20 30 40 50 60 70 

n 

L [h] 

p 

GDR γ 

Maria Kmiecik 


Energy spectrum of emitted γ rays 

37 

Ar 

1 

2 

3 

4 

Continous spectrum 

Maria Kmiecik 


Extraction of GDR parameters 

10 2 

σ 

( E ) 

γ 

= 

2 2 

2 2 

( E − E ) + Γ E 

γ 

SΓE 

GDR 

γ 

2 

γ 

0.10 

Zliczenia [a. u.] 

Y γ 

10 1 

10 0 

10 -1 

10 -2 

10 -3 

CASCADE 

detector’s response 

function 

0.06 

0.02 

Γ 

6 10 14 18 22 

E [MeV] 

γ 

10 -4 

χ 2 - minimization 

10 -5 

5 10 15 20 25 

E γ [MeV] 

0.10 

σ 

( E ) 

deformation parameter 

of nucleus 

γ 

= 

1 

1 

2 2 

2 2 2 2 

2 2 

( E − E ) + Γ E ( E − E ) + Γ E 

γ 

S Γ E 

GDR 1 

2 

γ 

1 

γ 

+ 

γ 

S 

2 

Γ 

2 

GDR 2 

E 

2 

γ 

2 

γ 

0.06 

0.02 

E − E 

β ≈ 106 . 

2 1 

6 10 14 18 22 

E GDR E [MeV] γ 

Maria Kmiecik 


Thermal shape fluctuations 

probability of existing a nucleus 

at given shape (described by β and γ) 

⎡ 

P ( T , ϖ ; β , γ ) ∝ exp − 

⎣⎢ 

F ( T , ϖ ; β , γ ) ⎤ 

T ⎦⎥ 

Shapes ensemble 

Maria Kmiecik 


Thermal shape fluctuations 

P( β , γ ) 

∝ 

e 

− F ( β , γ ) 

T 

β eq 

0.4 

0.3 

106-110 Sn T~1.8 MeV 

β eq 

∆β 

0.2 

0.1 

∆β 

0.0 

0 10 20 30 40 50 60 

I [h] 

β eq 

eq 

~ I 

∆β ~ T 

β equilibrium 

(the 

most probable) 

f 

GDR strength function (average – measured): 

av 

GDR 

∫∫ 

−F 

( T , I ; β , γ )/ T ( I ; β , γ ) 4 

( T, 

I ) = f ( β, 

γ , ω) 

e 

β sin(3γ 

) dβdγ 

GDR 

Maria Kmiecik 


HECTOR (High Energy gamma-ray deteCTOR) array: 

(Copenhagen)-Milano-Kraków collaboration since 1989 

HECTOR - 8 large BaF 2 detectors 

high energy 

γ-ray spectra 

10 2 

10 1 

10 0 

Zliczenia 

10 -1 

10 -2 

10 -3 

10 -4 

10 -5 

5 10 15 20 25 

E γ [MeV] 

neutron discrimination using time of flight 

time 

time 

HELENA multiplicity filter (38 small BaF 2 ) 

counts 

sum energy 

fold (measured 

multiplicity) 

σ [mb] 

22 

18 

14 

10 

E lab 

= 170 MeV 

E lab 

= 165 MeV 

E lab 

= 160 MeV 

fold 5-30 

fold 8-30 

channel 

spin distributions 

6 

2 

fold 5-7 

0 10 20 30 40 50 60 

l [h] 

Maria Kmiecik 


Measurements 

EB IV + HECTOR + EUCLIDES exp. 

HECTOR + NORDBALL 

 

 

 

 

HECTOR – GDR 

EUROBALL, 

NORDBALL, PEX – 

discrete transitions 

multiplicity filter 

(spin) HELENA 

light charged 

particles 

(EUCLIDES, 

GARFIELD) 

HECTOR + PEX 

GARFIELD 

HECTOR 

Maria Kmiecik 


The dependence 

of the GDR width 

on angular momentum 

Maria Kmiecik 


GDR width Γ and deformation parameter β 

for 147 Eu 

M. Kmiecik et al. Nucl. Phys. A674 (2000) 29 

Γ [MeV] 

10.5 

10.0 

9.5 

9.0 

8.5 

8.0 

7.5 

0.4 

0.3 

170 MeV, 165 MeV, 160 MeV 

Γ (T=1.2) 

Γ (T=1.4) 

Γ global (T=1.3) 

β av (T=1.2) 

β av (T=1.4) 

β 

av 

∆β 

= 

F 

D α − 

−1 

[ ] β 

T 

= Z ∫ 3 

e , Z = 

2 

I 

β 

2 

for ∆β 

> β 

for β 

eq 

eq 

> ∆β 

− β 

β 

β 

2 

av 

av 

av 

∫ 

slightly ↑ 

D[ α] 

3 

e 

2 

I 

for 

I 

↑ strongly with 

↑ 

I 

F 

− 

T 

↑ 

β 

0.2 

0.1 

β eq (T=1.2) 

β eq (T=1.4) 

0.0 

0 10 20 30 40 50 60 

 [h] 

The GDR width increases 

due to deformation increase 

and thermal shape fluctuations 

Maria Kmiecik 


Isomer gated GDR 96 MeV 18 O + 198 Pt → 216 Rn * 

M. Kmiecik et al. PR C70, 064317 (2005) 

E * =56MeV, L max =39h 

Γ [MeV] 

β 

9 

8 

7 

6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 

exp. fold gated 

exp. isomer gated 

calc. Kusn. 

calc. LSD 

β eq 

 

 

0 10 20 30 40 50 

I [h] 

fission 

no significant increase 

of GDR width observed 

small deformation 

up to the fission limit 

gating on isomers – 

choosing nuclei 

at highest spins 

surviving fission 

0.0 

0.0 

0.5 

0.5 

1.0 

1.0 

β 2 

cos(γ+30 o ) 

1.5 -0.5 0.0 0.5 0.0 0.5 

1.5 -0.5 0.0 0.5 0.0 0.5 

1.0 

1.0 

1062 

63/2 - 201 ns 

687 

769 

1299 

43/2 - 854 

14 ns 

211 Rn 

1.5 -0.5 0.0 0.5 0.0 0.5 

1.5 -0.5 0.0 0.5 0.0 0.5 

30 + 

I = 10 I = 16 I = 22 

β eq 

I = 28 I = 34 

 

22 + 212 Rn 

924 

1117 

701 

736 

154 ns 

968 

109 ns 

Maria Kmiecik 

International Workshop on Acceleration and Applications of Heavy Ions, Warszawa 2011 

1.0 

1.0 

1.5 -0.5 0.0 0.5 

I = 40 

1.5 -0.5 0.0 0.5 

β 2 

sin(γ+30 o )

The GDR width at finite temperature 

Γ [MeV] 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

147 Eu T=1.3 

106 

Sn T=1.8 

176 

W T=1.5 

194 

Hg T=1.3 

216 

Rn T=0.75 

0 10 20 30 40 50 60 

 [h] 

Ι = I⋅ϖ 

I ∝ 

A 5/ 

3 

larger deformation increase 

(at the same spin) 

for nuclei of smaller mass 

effect of rotational frequency 

M.Mattiuzzi et al. Nucl. Phys. A612 (1997) 262 

M. Kmiecik et al. Nucl. Phys. A674 (2000) 29 

M. Kmiecik et al., Phys. Rev. C70, 064317 (2005) 

F. Camera et al. Phys. Rev. C60 (1999) 014306 

Maria Kmiecik 


The GDR width Γ behaviour 

as a function of nuclei 

temperature 

Maria Kmiecik 


The temperature evolution of GDR width 

Γ GDR saturation? 

G. Enders et al., PRL 69 (1992) 249 

A. Bracco et al., PRL 62 (1989) 2080 

T=2.5 

T=3.5 

Possible explanations: 

- saturation of the transferred 

angular momentum 

- preequilibrium emission 

P.M.Kelly et al. PRL82 (1999) 3404 

Maria Kmiecik 


The temperature evolution of GDR width 

Calculations for 132 Ce 

Shape probability 

distribution 

Effective GDR width 

increases with T 

Maria Kmiecik 


The GARFIELD+HECTOR experiment 

(γ rays and charged particles measured) 

132 

Ce 

O. Wieland et al., Phys. Rev. Lett. 97, 012501 (2006) 

The GDR width increases with temperature (up to 4 MeV). 

The results are in agreement with calculations based on thermal 

shape fluctuation model including compound nucleus life time. 

Maria Kmiecik 


Jacobi shape transition 

Maria Kmiecik 


Theoretical shapes of rotating gravitating body 

Colin MacLaurin (1742) showed that, as the angular momentum increases, the spherical body (Earth) 

will become more flat (oblate). It changes it’s s shape to an ellipsoid with two equal long axes, 

rotating around the short axis. 

McLaurin McLaurin shapes: spherical → oblate → more flat oblate 

24h 2,3h 

Jacobi shapes: 

Carl Gustav Jacob Jacobi in 1834 

calculated that at certain angular 

velocity the rotating body 

(gravitating mass rotating 

synchronously) may change abruptly 

the shape from MacLaurins oblate 

shape to triaxial and then more 

elongated. (Jacobi( 

bifurcation). 

Jacobi shapes 

2.4h 

oblate → triaxial → prolate 

Poincare shapes: 

2,4h 3,8h 

Poincare shapes 

2.5h 

Henri Poincare (1885) described new shapes that 

could be obtained by rotating mass at the Jacobi 

path at given angular velocity. The body having 

Jacobi elongated triaxial shape can change it at 

multiple bifurcation point a pear shape 

triaxial → 

pear shape 

Maria Kmiecik 


Evolution of the shape of hot nucleus 

as a function of spin 

R L 

/R S 

2.0 

1.5 

1.0 

β 

168 

Hf 

2 

126 Ba Ba 

168 Hf 

0 10 20 30 40 50 60 70 80 

spherical 

oblate 

fission 

0.2 

0.1 

0.0 

R L 

/R S 

2.0 

1.5 

1.0 

spherical 

oblate 

triaxial 

prolate 

fission 

β 2 

0.3 

0.2 

0.1 

0.0 

0 10 20 30 40 50 60 70 80 

0.2 

I [h] 

”Oblate”→fission 

I [h] „Jacobi shapes” 

„Oblate” →3-axial→ 

→”prolate”→fission 

0.2 

0.16 

0.16 

σ 

0.12 

0.08 

σ 

0.12 

0.08 

0.04 

0.04 

0 

5 10 15 20 25 25 

30 30 35 

30 35 

35 

E γ [MeV] 

0 

5 10 15 20 

20 25 25 

30 30 

35 

35 

35 

E γ [MeV] 

Maria Kmiecik 


Jacobi shape transition - theoretical predictions 

potential energy calculated 

with LSD (Lublin-Strasbourg Drop) model: 

Dudek & Pomorski Phys. Rev. C67 (2003) 044316 

equilibrium shape evolution 

60 

50 

46 Ti 

40 

30 

γ 

20 

Jacobi shape transition 

28 29 

1826 

30 

10 

0 

32 34 36 

0 

0.0 0.5 1.0 1.5 

average shape 

Maria Kmiecik 

International Workshop on Acceleration and Applications of Heavy Ions, Warszawa 2011 

β 

10

Jacobi shape transition – GDR strength function 

0.28 

0.24 

0.20 

0.16 

0.12 

0.08 

0.04 

0.00 

triaxial 

I=27 h 

0 5 10 15 20 25 30 35 

E [MeV] 

0.28 

0.24 

0.20 

0.16 

0.12 

0.08 

0.04 

0.00 

prolate 

I=34 h 

0 5 10 15 20 25 30 35 

E [MeV] 

0.28 

0.24 

0.20 

oblate 

I=25 h 

60 

0.16 

0.12 

50 

0.08 

0.04 

0.00 

0 5 10 15 20 25 30 35 

E [MeV] 

46 Ti 

40 

30 

γ 

0.28 

0.24 

0.20 

0.16 

0.12 

0.08 

0.04 

0.00 

spherical 

I=0 h 

0 5 10 15 20 25 30 35 

E [MeV] 

28 29 

1826 

30 

10 

0 

32 34 36 

20 

10 

0 

0.0 0.5 1.0 1.5 

β 

Maria Kmiecik 


First signatures 

of Jacobi shape 

transition 

predictions 

 

M. Kicińska 

ska-Habior et al., 

Phys. Lett. B308 (1993) 225: 

Seattle exp. - Possible 

signature of the Jacobi shape 

transition for 45 Sc in the 

inclusive GDR spectrum 

0.28 

0.24 

0.20 

0.16 

0.12 

0.08 

0.04 

triaxial 

I=27 h 

0.00 

0 5 10 15 20 25 30 35 

E γ [MeV] 

E [MeV] 

β = 0.4, γ = -30 o 

5 10 15 20 25 

0.08 

0.06 

0.04 

0.02 

0.4 

0.2 

 

A. Maj et al, 

Nucl. Phys. A687 (2001) 192: 

NBI exp. – Possible signatures 

of the Jacobi shape transition 

for 46 Ti in the multiplicity 

gated GDR spectra and angular 

distributions 

0.0 

-0.2 

-0.4 

5 10 15 20 25 30 

E γ [MeV] 

Maria Kmiecik 


HECTOR+EUROBALL experiment 

105 MeV 18 O + 28 Si ⇒ 46 Ti* 

L max ≈ 35 h 

E* = 85 MeV 

0.12 

A. Maj et al., Nucl. Phys. A731 (2004) 319c. 

0.12 

fold 2 

fold 6 

folds 11-20 

multiplicity 

gated 

0.08 

high spin 

folds 11-20 

0.08 

low spin 

fold 2 

[arb. units] 

10 4 

10 3 

[arb. units] 

Y γ 

0.04 

[arb. units] 

Y γ 

0.04 

Y γ 

10 5 E γ [MeV] 

10 2 

0.00 

4 8 12 16 20 24 28 

0.00 

4 8 12 16 20 24 28 

10 1 

E γ [MeV] 

E γ [MeV] 

4 8 12 16 20 24 

low energy component increasing with spin 

gated with 

γ transitions 

in 42 Ca residuum 

Maria Kmiecik 


Coriolis splitting of the GDR components 

0.08 

0.06 

0.04 

0.02 

I=0 

low E 

high E 

prolate 

β=0.5 

ω=0 

K. Neergård, Phys. Lett. 110B (1982) 7 

Ω 

2 

2,3 

∆ = 

2 

ω 

2 

= 

1 

4 

2 

+ ω 

3 

2 

2 

+ ω ± 

2 2 2 2 2 2 

( ω − ω ) + ω ( ω + ω ) 

2 3 

2 

J.J. Gaardhøje, A. Maj et al., 

Acta. Phys. Pol. B24 (1993) 139; 

T. Døssing, private communication 

∆ 

2 

3 

0 

5 10 15 20 25 30 

E [MeV] 

ω 

Frequency 

= 0 ω 

> 

0 

0.08 

0.06 

0.04 

0.02 

0 

I=30 

5 10 15 20 25 30 

E [MeV] 

ω=2.8 

(I=30 for A=46) 

ω 1 

ω 2 

ω 3 

ω 

1 

Ω 2 

Ω 2 

Ω 3 

Ω 3 

+ ω 

− ω 

+ ω 

− ω 

Maria Kmiecik 


LSD calculations 

thermal shape 

fluctuations + 

Coriolis splitting 

P(β,γ) ∝ exp(-F(b,g)/T) 

46 

Ti 

β 2 

sin(γ+30 o ) 

γ = 60 o 

0.75 

0.50 

0.25 

0.00 

0.0 

0.5 

γ = 0 o 

I = 24 

1.0 

β 2 

cos(γ+30 o ) 

γ = 60 o 

0.75 

0.50 

0.25 

1.5 

0.00 

0.0 

γ = 0 o 

I = 28 - 34 

1.0 

0.5 

β 2 

cos(γ+30 o ) 

1.5 

f 

av 

GDR 

∫∫ 

−F( 

T, 

I; 

γ γ 

T I f β γ ω e 

β , )/ T ( I; 

= β , ) 4 

( , ) ( , , ) 

β sin(3 γ) 

dβdγ 

GDR 

Jacobi shape transition and 

indicated for the first time 

Coriolis effect 

[a. u.] 

Y γ 

Exp. LSD (I = 28-34) LSD (I = 24) 

with Coriolis 

A. Maj et al., Nucl. Phys. A731, 319c (2004) 

0 5 10 15 20 25 30 35 

E [MeV] γ 

Maria Kmiecik 


GDR built on superdeformed 

nucleus 

Maria Kmiecik 


GDR built on superdeformed nucleus - predictions 

60 

yrast ND 

β≈0.2 

50 

yrast SD 

β≈0.6 

E [MeV] 

40 

30 

20 

10 

F 

GDR 

ND 

5 10 15 20 25 30 

F 

GDR 

SD 

5 10 15 20 25 30 

B n 

B n 

0 

0 10 20 30 40 50 60 

l [h] 

Maria Kmiecik 


GDR built on superdeformed nucleus - indications 

37 

Cl(165 MeV) on 110 Pd ⇒ 147 Eu* 

1000 

100 

SD Gated 

TD gated 

143 

Eu 

F. Camera et al., Acta Phys. Pol. B32 (2001) 807 

a.u. 

gated on SD band 

10 

110 Pd( 37 Cl,4n) 143 Eu 

SD / TD 

1 

6 8 10 12 

Energy [MeV] 

Maria Kmiecik 


Feeding of highly deformed states by GDR - 

42 Ca case 

2.5 

2.0 

sd sd / sfer / spher 

nd nd / sfer / spher 

sd / ndsd / nd 

feeding of the highly deformed states 

by the low energy GDR component 

Ratio 

1.5 

1.0 

0.5 

0.0 

2 4 6 8 10 12 

E γ [MeV] 

nd 

sd 

Exp. LSD (I = 28-34) LSD (I = 24) 

with Coriolis 

spher 

[a. u.] 

Y γ 

M. Kmiecik et al., Acta Phys. Pol. B36 (2005) 1169 

0 5 10 15 20 25 30 35 

E [MeV] γ 

Maria Kmiecik 


Search for highly deformed states in 42 Ca using Coulomb 

excitation – AGATA Demonstrator experiment 

Experiment proposed by Adam Maj (IFJ PAN Krakow), 

Paweł Napiorkowski (HIL Wrasaw) 

and Faical Azaiez (IPNO Orsay) 

goal: 

investigate the deformation of nucleus 

at states from the highly deformed band 

reaction: 

Coulomb excitation 42 Ca on 208 Pb target 

measured: 

•γ rays 

•back-scatered 

projectiles 

Maria Kmiecik 


Isospin mixing studies 

in Heavy Ion Laboratory 

in Warsaw 

Maria Kmiecik 


GDR studies in Warszawa 

 

JANOSIK set-up 

 

 

25 cm x 29 cm NaI(Tl) 

detector for high-energy 

γ-ray measurement 

with shield (plastic + 6 LiH 

+ lead) to reduce cosmic 

background 

Si-Ball – p and α detection 

M. Kicińska-Habior et al., Acta Phys. Pol. B27 (1996)547, 

Acta Phys. Pol. B28 (1997)219 

 

Isospin mixing investigations 

GDR measured for two neighbouring 

N=Z and N≠Z nuclei at similar excitation energies 

N≠Z – GDR parameters extracted 

– statistical model Cascade 

N=Z – α 2 (isospin mixing probabilty) obtained 

M. Kicińska-Habior et al., Acta Phys. Pol. B36 (2005) 1133 

Maria Kmiecik 


Isospin mixing 

M. Kicińska-Habior et al., Nucl. Phys. A731c (2004) 138 

E. Wójcik et al., Acta Phys. Pol. B37 (2006) 207 

E. Wójcik et al., Acta Phys. Pol. B38 (2007) 1469 

Maria Kmiecik 


Isospin mixing studied by HECTOR collaboration 

81 

Rb (N≠Z) 80 

Zr (N=Z) 

A. Corsi et al., to be published 

Maria Kmiecik 


Perspectives 

Maria Kmiecik 


Theoretical predictions for Jacobi shape transition 

- examples 

6 

5 

4 

3 

2 

1 

0 

Zn 

71 71 Zn 

I = 40 

I = 48 

I = 62 

0 5 10 15 20 25 30 35 40 

E [MeV] 

44 

40 

30 

20 

10 

60 

50 

∆I=22 

40 

30 

46 48 50 54 56 60 64 

72 70 68 

20 

10 

0 

0.0 0.5 1.0 1.5 

β 

γ 

wide spin window for Jacobi shapes 

large spins 

6 

5 

4 

3 

2 

1 

0 

Cd 

98 98 Cd 

I = 50 

I = 58 

I = 72 

0 5 10 15 20 25 30 35 40 

E [MeV] 

50 

40 

20 

0 

60 

50 

∆I=22 

40 

30 

54 58 62 6668 70 74 72 

0.0 0.5 1.0 1.5 

β 

20 

γ 

10 

0 

6 

5 

4 

3 

2 

1 

0 

Cd 

120 120 Cd 

I = 66 

I = 72 

I = 92 

0 5 10 15 20 25 30 35 40 

E [MeV] 

68 66 60 

50 

40 

20 

60 

50 

∆I=32 

40 

30 

72 70 76 80 88 84 92 100 96 

20 

10 

0 

0.0 0.5 1.0 1.5 

β 

γ 

Maria Kmiecik 


I 

Future experiments 

Possible with high intensity radioactive beams 

that will be available at new facilities 

(e.g. SPIRAL2) 

68 28 Ni + 30 14 Si → 98 42 Mo; 

10 8 pps 

E b 

= 500MeV, I max 

= 85 h, E* = 150 MeV 

58 28 Ni + 28 14 Si → 86 42 Mo; 

stable 

E b 


= 68 h, E* = 110 MeV 

6 

5 

4 

3 

2 

1 

0 

6 

5 

4 

3 

2 

1 

98 Mo 

I = 58 

I = 64 

I = 80 

0 5 10 15 20 25 30 35 40 

E [MeV] 

23 10 Ne + 48 20 Ca → 71 30 Zn; 

10 6 pps 

E b 


= 70 h, E* = 160 MeV 

71 Zn 

I = 40 

I = 48 

I = 62 

Summary of the experimental 

programme for GANIL 

105 

120Cd 

98Cd 

95 

98Mo 

85 

86Mo 

71Zn 

75 

44Ti 

65 

55 

45 

35 

25 

15 

5 

0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 

ω= I / J 

94 36 Kr + 26 12 Mg → 120 48 Cd; 

10 10 pps 

E b 


= 100 h, E* = 190 MeV 

40 20 Ca + 58 28 Ni → 98 48 Cd; 

stable 

E b 


= 78 h, E* = 120 MeV 

6 

5 

4 

3 

2 

1 

0 

6 

5 

4 

3 

2 

1 

120 Cd 

0 5 10 15 20 25 30 35 40 

E [MeV] 

44 Ti 

I = 66 

I = 72 

I = 92 

12 6 C + 32 16 S → 44 22 Ti 

stable 

E b 


= 38 h, E* = 130 MeV 

I = 26 

I = 30 

I = 36 

0 

0 5 10 15 20 25 30 35 40 

E [MeV] 

0 

0 5 10 15 20 25 30 35 40 

E [MeV] 

Maria Kmiecik 


Poincare shapes investigations 

Poincare shapes predicted for the first time 

New calculations based on the LSD model, 

allowing odd-rank deformation parameters 

30 , α 50 , α 70 ) be free: 

(α 30 

K. Mazurek, J. Dudek et al., Acta Phys. Pol. (2011) in print 

A.Maj, K. Mazurek, J. Dudek, M. Kmiecik, D. Rouvel 

“Shape evolution at high spins and temperatures: nuclear Jacobi 

and Poincare transition”, J. Mod. Phys. E19 (2010) 53 

to be observed in the GDR strength function 

At GANIL –SPIRAL2 (later stage: Phase2-Day2) 

94 Kr + 48 Ca → 142 Ba 

Maria Kmiecik 


New very efficient high-energy γ-ray detector 

PARIS desing concepts: 

- high efficiency detector consisting of phoswich detectors 

for medium resolution spectroscopy 

and calorimetry of γ rays in large energy range 

Phoswich detector will consit of new LaBr 3 (Ce) 5 x 5 cm 

crystals and conventional crystals NaI. 

The first stage will be the prototype made of 9 phoswich 

detectors. 

prototype 

PARIS will be used as a high and low-energy photon deterctor, 

multiplicity filter of high resolution and sum-energy detector 

(calorimeter), 

It will be mechanically compatible with other detectors: e. g. 

AGATA, GASPARD 

Maria Kmiecik 


Summary 

The GDR strength functions (lineshape) measurements 

deliver information on properties of nucleus (at ground and 

exited state) 

At given temperature the shape of the nucleus is described 

by the shape distribution 

The deformation of nucleus increases with spin due to increase 

of angular momentum and it is larger for higher rotational frequency 

The thermal shape fluctuations are important in describing 

shapes of nuclei as a function of temperature 

At high temperatures the CN life time has to be taken into account 

The GDR can be built on superdeformed structure, and low energy 

component feeds the highly deformed states. 

The GDR spectra measurements provide information about isospin mixing 

coefficient 

Perspectives for future investigations concern Jacobi 

and Poincare shape transitions at new facilities 

with radioactive beams 

The new, very efficient detector PARIS is developed 

Maria Kmiecik 


Thanks to 

Kraków: Adam Maj, Kasia Mazurek, Michał Ciemała, Mirek Ziębliński ……. 

Milano: Angela Bracco, Franco Camera, Oliver Wieland, Silvia Leoni, 

Anna Corsi, ………. 

Warszawa: Marta Kicińska-Habior 

……….. 

Maria Kmiecik

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