CoulombDissociation of Nakamuralaboratory Kazuhiro Ishikawa 02 M 01020

Coulomb　Dissociation of Nakamura-laboratory Kazuhiro Ishikawa 02 M 01020 26 Ne

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

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

Introduction RIPS

Neutron-rich nuclei

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

In the case of 26 Ne

Experimental Method Coulomb Dissociation Using High Z target Calculated by equivalent photon method Cross section = photon number × B(E 1)

Experimental Setup DALI

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

Data Analysis Silicon Strip Detector

Particle Identification Upstream of the Target Pulse Height versus TOF ΔE～Z 2/v 2=Z 2 TOF 2

Particle Identification Downstream of the Target ΔE=ΔEX＋ΔEY Ekin=E+ΔE ΔE=Z 2/v 2 Ekin=Av 2/2 EkinΔE～AZ 2 A: mass Z: charge

Mass Spectrum of Ne Fragments AZ 2～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

Results and Discussions Neutron Counter

Reaction Cross Section (mb) Pb Al ε：εn~30% Run 26 Ne+pb 26 Ne+Al 25 Ne 119(2) 10(0. 3) 24 Ne 211(3) 29(0. 6) 23 Ne 167(3) 22(0. 5) 22 Ne 197(3) 31(0. 7)

Cross Section Ratio for 25 Ne is high! 1. Coulomb dissociation for 25 Ne 2. Hindrance of σ (Al) for 25 Ne , 3. 25 Ne+Al→ 24 Ne+n+x

Angular Distribution of Ne Fragments Al Two components are seen. Pb

Estimation of the width by the fragmentation model AP : Projectile mass From Fermi motion Target Deflection A : Fragment mass F EF : Fragment energy =87 Me. V/c =200~300 Me. V/c

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

Conclusion Electronics

for 25 Ne Coulomb dissociation for the reaction Angular distributions , wide) 1. 2. Large 26 Ne+Pb→ 25 Ne+n Two components (narrow wide component : In agreement with fragmentation model (nuclear component) narrow component : Further investigations are necessary (Coulomb component? )

Special thanks to R 332 n Collaborators Julien Gibelin. B, Koichi Yoshida. E, Takashi Nakamura. A, Dider Beaumel. B, Nori Aoi Hidetada Baba. D, Yorick Blumefeld. B, Zoltan Elekes. E, Naoki Fukuda. E, Tomoko Gomi. D, Yosuke Kondo. A, Akito Saito. D, Yositeru Sato. A, Eri Takeshita. D, Satoshi Takeuchi. E, Takashi Teranisi. C, Yasuhiro Togano. D, Victor Lima. B, Yoshiyuki Yanagisawa. E, Attukalathil Mayyan Vinodkumar. A, Toshiyuki Kubo. E, Tohru Motobayashi. E 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