1. Coulomb Dissociation of 26Ne
Nakamura-laboratory
Kazuhiro Ishikawa
02M01020

2. Contents Motivation Introduction Experimental Setup Data Analysis
Results and Discussions
Conclusion

3. Motivation Search for the Soft Dipole Resonance (SDR) in 26Ne
Coulomb Dissociation
Nuclear Breakup
Breakup
Develop a method to distinguish two components

4. Introduction
RIPS

5. Neutron-rich nuclei

6. Giant Dipole Resonance (GDR) versus Soft Dipole Resonance (SDR)
stable nuclei
E1 strength is almost exhausted by Giant Dipole Resonance (GDR). Ex=80A-1/3 MeV（～20 MeV 20Ne)
unstable nuclei
low lying E1 strength
Soft Dipole Resonance (SDR)
Prediction
Low Ex（　8 MeV 26Ne)

7. In the case of 26Ne

8. Experimental Method Coulomb Dissociation
Using High Z target
Experimental Method Coulomb Dissociation
Calculated by equivalent photon method
Cross section = photon number × B(E1)

9. Experimental Setup
DALI

11. Experimental Setup Reaction Target Pb: Coulomb Dissociation
Al : Nuclear Breakup

12. Data Analysis
Silicon
Strip Detector

13. Particle Identification Upstream of the Target
Pulse Height versus TOF
ΔE～Z2/v2=Z2TOF2

14. Particle Identification Downstream of the Target
ΔE=ΔEX＋ΔEY
Ekin=E+ΔE
ΔE=Z2/v2
EkinΔE～AZ2
A: mass Z: charge
Ekin=Av2/2

15. Mass Spectrum of Ne Fragments
AZ2～ΔEE’kin=ΔE(E+ΔE/2)b (Z=10)
b=0.75
Removal of beam contaminants
Selecting of Angle(1~6 degree)
Neutron Tagged
Select specific mass　 Reaction Cross Section
Angular Distribution

16. Results and Discussions
Neutron Counter

17. Reaction Cross Section
Cross Section (mb) Pb
Run
26Ne+pb
26Ne+Al
25Ne
119(2)
10(0.3)
24Ne
211(3)
29(0.6)
23Ne
167(3)
22(0.5)
22Ne
197(3)
31(0.7) Al
ε：εn~30%

18. Cross Section Ratio Ratio for 25Ne is high!
Coulomb dissociation for 25Ne
Hindrance of σ (Al) for 25Ne ,
25Ne+Al→24Ne+n+x

19. Angular Distribution of Ne Fragments
Al Pb
Wide and Narrow
Two components are seen.

20. Estimation of the width by the fragmentation model
AP : Projectile mass
AF : Fragment mass
EF : Fragment energy
From Fermi motion
Target Deflection
=87 MeV/c
=200~300 MeV/c

21. This result for wide is agreement with Goldhaber model.
Al wide＋
Pb wide×
Al narrow＊
Pb narrow■
σ⊥(MeV/c)
This result for wide is agreement with Goldhaber model.
Wide
Narrow

22. Conclusion
Electronics

23. Coulomb dissociation for the 26Ne+Pb→25Ne+n reaction
for 25Ne Large
Coulomb dissociation for the 26Ne+Pb→25Ne+n reaction
Angular distributions Two components (narrow ,wide)
wide component : In agreement with fragmentation model (nuclear component)
narrow component : Further investigations are necessary (Coulomb component?)

24. Special thanks to R332n Collaborators
Julien GibelinB, Koichi YoshidaE, Takashi NakamuraA, Dider BeaumelB, Nori AoiE, Hidetada BabaD, Yorick BlumefeldB, Zoltan ElekesE, Naoki FukudaE, Tomoko GomiD, Yosuke KondoA, Akito SaitoD, Yositeru SatoA, Eri TakeshitaD, Satoshi TakeuchiE, Takashi TeranisiC, Yasuhiro ToganoD, Victor LimaB, Yoshiyuki YanagisawaE, Attukalathil Mayyan VinodkumarA, Toshiyuki KuboE, Tohru MotobayashiE
A: Department of Physics. Tokyo Institute of Technology
B: Institut de Physique Nuclaire, Orsay, France
C: University of Tokyo (CNS), Riken Campus
D: Department of Physics, Rikkyo University
E: The Institute of Physics and Chemical Research (Riken)
Nakamura-laboratory
Takashi Sugimoto, Nobuyuki Matsui, Masako Ohara, Takumi Nakabayashi, Yoshiko Hashimoto