1. for NEWCHIM-ISODEC Collaboration
International Workshop  Nuclear Reactions on Nucleons and Nuclei  Messina (Italy) - October 25-26, 2017
Isospin influence on the reaction mechanisms in the78Kr+40Ca and 86Kr+48Ca collisions at 10 AMeV
Brunilde Gnoffo
for NEWCHIM-ISODEC Collaboration
Istituto Nazionale di Fisica Nucleare - Sezione di Catania
Università degli Studi di Catania

2. Heavy-ion induced reactions with stable and radioactive beams are ideal to explore the nuclei under different stress conditions.
The isospin influence is expected to play a crucial role in the reaction dynamics
Low energy regime E < 15 MeV/A is dominated by Compound Nucleus formation and de-excitations in competition with binary processes (DIC, Quasi-Fission)
N/Z ratio, connected to the isospin degree of freedom, influences:
Fragments formation
Reaction mechanisms
Competition among the different decay channels of the Compound Nucleus
Physics Case

3. 78Kr + 40Ca -> 118Ba* 86Kr + 48Ca -> 134Ba* Experimental method
@E/A=10 MeV/A
118Ba
134Ba
E*(MeV)
215
270
(N/Z)tot
1.11
1.39
S. Pirrone et al., Journal of Physics: Conf. Series 515 (2014)
G. Politi et al., JPS Conf. Proc. Vol. 6 (2015)
B. G. Il Nuovo Cimento C39 (2016) 275
CHIMERA at INFN-LNS
A. Pagano et al., NPA681 (2001)331

4. 78Kr + 40Ca -> 118Ba* 86Kr + 48Ca -> 134Ba* Experimental method
@E/A=10 MeV/A
118Ba
134Ba
E*(MeV)
215
270
(N/Z)tot
1.11
1.39
S. Pirrone et al., Journal of Physics: Conf. Series 515 (2014)
G. Politi et al., JPS Conf. Proc. Vol. 6 (2015)
B. G. Il Nuovo Cimento C39 (2016) 275
78,82Kr + 40Ca -> 118,122Ba* @ E/A=5.5 MeV/A E* ≈ 100 MeV
INDRA at GANIL
G. Ademard et al. PRC 83 (2011)
Composite systems with higher E -> effects on decay
Larger domain of N/Z (max with stable beam)
CHIMERA at INFN-LNS
A. Pagano et al., NPA681 (2001)331

5. Experimental results
TKE reconstructed from fragment kinematical characteristics
in inclusive analysis

6. Experimental results
TKE reconstructed from fragment kinematical characteristics
in inclusive analysis
Dynamical mechanism
with TKE > 150 MeV
and small ϑcm

7. Experimental results
TKE reconstructed from fragment kinematical characteristics
in inclusive analysis
Dynamical mechanism
with TKE > 150 MeV
and small ϑcm
Relaxed process
with TKE ~ 85 MeV
for any angle
Value in agreement with a compilation
of C. Beck and S. de Toledo on fission energy release
C.Beck and A. S. de Toledo, Phys. Rev. C 53, 1989 (1996)
Analogue results for n-rich system, with DIC even more present

8. Mtot - Ptot plot for complete events selection:
Experimental results
Mtot - Ptot plot for complete events selection:
0.8*ACN ≤ Atot ≤ 1.1*ACN
0.6 ≤ ptot/pbeam ≤1.1

9. Experimental results TKE measured in complete events condition
Relaxed process
with TKE ~ 85 MeV
for any angle
Value in agreement with
the values obtained in
the calculation for the
inclusive analysis
TKE measured in complete events condition
TKE calculated in inclusive analysis

10. Further information from Complete Events
Experimental results
Further information from Complete Events
Correlation between fragment mass and parallel velocity
Fission-Like processes are enhanced in the n-poor system
Mostly Binary decay is presents in both systems
-> Important information on the interplay between mechanism

11. Further information from Complete Events
Experimental results
Further information from Complete Events
Correlation between fragment mass and parallel velocity
Fission-Like processes are enhanced in the n-poor system
Mostly Binary decay is presents in both systems
-> Important information on the interplay between mechanism
Evaporation
Fission Like

12. Experimental results
Average velocity for Z= 3-38 in the c.m. frame for different Z and at different θlab
-> Energy and velocity spectra in c.o.m frame pratically independent of the emission
angles and decresing with Z
-> Good agreement with Viola-Hinde systematic
-> Regular behavior slightly disregarded for Z>30, maybe due to the dynamic
mechanism contribution

13. Experimental results
Angular distributions in the center of mass frame for Z from 10 up to 38
1/sinθ behaviour -> high degree of relaxation, long lived system

14. Experimental results
Angular distributions in the center of mass frame for Z from 10 up to 38
1/sinθ behaviour -> high degree of relaxation, long lived system
Z>28 ->Stronger contribution at smaller angles->not fully
equilibrated binary mechanism

15. Experimental results Charge Distributions
-> Fragments production globally favored for n-poor
->Strong even-odd effect , staggering, more pronounced for the n-poor system
->Charge distribution asymmetric with respect to ZCN/2=28-> process not fully
relaxed in mass

16. Experimental results
Selection of complete events to get rid of very dissipative binary collisions
(TLF not detected)
78Kr + 40Ca
86Kr + 48Ca
inclusive
inclusive
Complete events
Complete events
Cross sections normalized to value for Z = 18
The dynamic process seems to influence fragment production starting
From Z >

17. Experimental results Reaction Cross sections
- Fusion Evaporation - ER: Z > 41 and by subtracting FL for heavier fragments
- Fission Like - FL: Z = /26 -> not affected by DIC
- Reaction: elastic scattering (quarter point recipe)
σER(mb)
σFL(mb)
σFus(mb)
qp 
σReac (mb)
78Kr+40Ca
455±70
850±120
1305±190
2390±250
86Kr+48Ca
400±60
530±85
930±145
2520±260

18. Experimental results Reaction Cross sections
- Fusion Evaporation - ER: Z > 41 and by subtracting FL for heavier fragments
- Fission Like - FL: Z = /26 -> not affected by DIC
- Reaction: elastic scattering (quarter point recipe)
σER(mb)
σFL(mb)
σFus(mb)
qp 
σReac (mb)
78Kr+40Ca
455±70
850±120
1305±190
2390±250
86Kr+48Ca
400±60
530±85
930±145
2520±260
-> Fusion Evaporation similar in the two systems
-> Fission Like more present for n-poor systems
-> Difference sReac - sFus probably due to the DIC,
more pronounced for the n-rich system

19. Comparison with GEMINI++ code
Experimental results
Comparison with GEMINI++ code

20. Comparison with Dinuclear System code
Experimental results
Comparison with Dinuclear System code
Sh.A.Kalandarov et al., PRC 93 (2016)

21. Correlation between sizes of the two biggest fragments
Experimental results
Correlation between sizes of the two biggest fragments ER FF QF
78Kr +40Ca M1
5.5 AMeV
10 AMeV M2
G. Ademard et al., PRC 83 (2011)
Present work

22. Experimental results
Correlation between sizes of the two biggest fragments
IMF production is more pronounced at high energy ER FF QF
78Kr +40Ca M1
5.5 AMeV
10 AMeV M2
Fission Like
Evaporation
G. Ademard et al., PRC 83 (2011)
Present work

23. Comparison of FF production cross sections in the reaction
Experimental results
Comparison of FF production cross sections in the reaction
78Kr +40Ca at two different energies
In agreement with : J. Boger et al., PRC 49 (1994) 1597

24. Preliminary study of ternary events
Correlation of FF and alpha emitted
Experimental results

25. Preliminary results of α-particle vpar-vper in the fragment’s frame
Experimental results
Preliminary results of α-particle vpar-vper in the fragment’s frame
78Kr + 10 AMeV
Present work
Vpar(cm/ns)
Vper (cm/ns)
PRELIMINARY
Z=6 frame
Compl Z=6 frame
Z=14 frame
Compl Z=14 frame
Z=26 frame
Compl Z=26 frame

26. Preliminary results of α-particle vpar-vper in the fragment’s frame
Experimental results
Preliminary results of α-particle vpar-vper in the fragment’s frame
78Kr + 10 AMeV
78Kr AMeV
Present work
Vpar(cm/ns)
Vper (cm/ns)
PRELIMINARY
G. Ademard et al., PRC 83 (2011)
Z=6 frame
Compl Z=6 frame
Z=14 frame
Compl Z=14 frame
Z=26 frame
Compl Z=26 frame

27. Experimental results
Preliminary results of α-particle vpar-vper in the light fragment’s frame
78Kr + 40Ca
PRELIMINARY
Vper(cm/ns)
86Kr + 48Ca
Vpar (cm/ns)

28. Conclusion and Outlook
Results of inclusive and complete events analysis of the reactions
78,86Kr + 40,48Ca at 10 AMeV are presented
N/Z ratio influences the competition among the different reaction channels:
DIC, FF, QF and ER
Conclusion and Outlook

29. Conclusion and Outlook
Results of inclusive and complete events analysis of the reactions
78,86Kr + 40,48Ca at 10 AMeV are presented
N/Z ratio influences the competition among the different reaction channels:
DIC, FF, QF and ER
Kinematical characteristics typical of an energy equilibrated system
Conclusion and Outlook

30. Conclusion and Outlook
Staggering in cross sections
DIC effects Z>28-30
Conclusion and Outlook

31. Conclusion and Outlook
Staggering in cross sections
DIC effects Z>28-30
Evaporation comparable but Fission more present for n-poor
Conclusion and Outlook

32. Conclusion and Outlook
Stronger IMF production at high energy for the n-poor System
Conclusion and Outlook

33. Conclusion and Outlook
Stronger IMF production at high energy for the n-poor System
Stronger α emission in symmetric fission respect to very
asymmetric and asymmetric fission-> for the n-rich system
Conclusion and Outlook

34. Conclusion and Outlook
Further analysis to be done:
- Study of three fragments events and in particular Projectile
like Fragment fission
- Analysis of Deep Inelastic Contribution as a function of N/Z
- Analysis of LCP in coincidence with ER and FF
Conclusion and Outlook

35. 92Kr + 40,48Ca 10 AMeV 132,140Ba* E* ~ 320 MeV (N/Z)CN =1.5
Conclusion and Outlook
( E. De Filippo, J. Frankland, S. Pirrone, G. Politi, P. Russotto)
(approved by the Scientific Advisory Committee at LNL)
92Kr + 40,48Ca 10 AMeV
132,140Ba* E* ~ 320 MeV (N/Z)CN =1.5
-> investigation of the evolution of the dynamics with isospin asymmetry
-> interplay between nuclear structure and reaction mechanism in the emission process

36. NEWCHIM – ISODEC collaboration
B. Gnoffo1,2, S. Pirrone1, G. Politi1,2, J.P. Wieleczko3, E. De Filippo1, P. Russotto1,2, M. Trimarchi1,4, M. Vigilante5,6, G. Ademard7, L. Auditore1,4, C. Beck8, I. Berceanu9, E. Bonnet3, B. Borderie7, G. Cardella1, A. Chibihi3, M. Colonna10, D. Dell’ Aquila5,6, J. D. Frankland3, E. Geraci1, M. La Commara5,6, G. Lanzalone11, P. Lautesse12, D. Lebhertz3, N. Le Neindre13, N.S. Martorana1,10, K. Mazurek3, A. Pagano1, E.V. Pagano2,10, M. Papa1, E. Piasecki14, F. Porto10, L. Quattrocchi1,2, F. Rizzo1,10, G. Spadaccini5,6, A. Trifirò1,4 and G. Verde1,7.
1 INFN Sezione di Catania, Italy
2 Dipartimento di Fisica e Astronomia, Università di Catania, Italy
3 GANIL Caen,France
4 Dipartimento di Fisica, Università di Messina, Italy
5 Dipartimento di Fisica, Università Federico II Napoli, Italy
6 INFN Sezione di Napoli, Italy
7 IN2P3 - IPN Orsay, France
8 IN2P3 - IPHC Strasbourg, France
9 IPNE, Bucharest, Romania
10 INFN Laboratori Nazionali del Sud, Italy
11Università Kore, Enna, Italy
12 IN2P3 - IPN Lyon, France
13 IN2P3 - LPC Caen, France
14 University of Warsaw, Poland