Fission research at JAEA and opportunity with J-PARC for fission and nuclear data

Transcription

1 Fission research at JAEA and opportunity with J-PARC for fission and nuclear data Katsuhisa Nishio Advanced Science Research Center Japan Atomic Energy Agency Tokai, JAPAN INT 13-3, Workshop, Seattle, Oct.2013

2 K. Nishio, H. Ikezoe, S. Mitsuoka, I. Nishinaka, H. Makii, Y. Wakabayashi, K. Hirose, K. Tsukada, M. Asai, Y. Nagame, A. Kimura, H. Harada A. Andreyev, D. Jenkins S. Hofmann, D. Ackermann, F.P. Heßberger, S. Heinz, J. Khuyagbaatar, B. Kindler, V.F.Comas J.A. Heredia, I. Kojouharov, B. Lommel, R. Mann, B. Sulignano, Ch.E. Düllmann, M.Schädel S. Chiba S. Antalic, S. Saro A.G. Popeko, A.V. Yeremin, A. Svirikhin A. Yakushev, A. Gorshkov, R. Graeger, A. Türler T. Ohtsuki, K. Hagino Y. Watanabe Y. Aritomo S. Yan N. Tamura, S. Goto

3 Fission Research Program at JAEA Tandem facility Fission study for heavy-element synthesis Fission of new region of chart of nuclei Multi-nucleon transfer induced J-PARC n TOF fission measurement and future

4 Tokai Campus, JAEA Tokyo J-PARC Tandem facility

5 JAEA Tandem facility 20 MV Tandem accelerator (20UR) Super-conducting Booster Liniac ECR Ion Source on the terminal Targets :Th,U,Np,Pu,Am,Cm,Cf

6 Fission Study for Heavy Element Synthesis How to determine fusion probability

7 Super-heavy Nuclei Proton 陽子数 Number Z Cold Fusion (GSI,RIKEN) Pb, Bi Targets Sg Db Bh Ds Mt Hs Rg 113 Cn 48 Ca + Actinide Target Nuclei (FLNR) Missing Region Deformed Shell Heavier Element Spherical Shell Using Radioactive Nuclei ± sf EC ² Neutron 中性子数 Number N Understanding for fusion using actinide target nuclei are important to explore SHN

8 Three steps for heavy-element synthesis S U Hs* Hs n (1) Contact (2) Fusion CN (3) Evaporation Quasifission Fusion- Fission 1 atom ~ Fusion probability

9 Fusion-fission and Quasi-fission Proton 78 Ni 132 Sn 238 U Neutron 208 Pb 274 Hs (Z=108) Potential Energy Compund Nucleus 2 3 Fusion S U Quasi-fission + Potential by Y. Aritomo

10 In-Beam Fission Measurement 30 Si, 31 P, 36,34 S, 40 Ar, 40,48 Ca Beams 200 mm 120 mm Fission Fragment 1 MWPC1 238 U Fission Fragment 2 MWPC2 Multi-Wire Proportional Counter 238 U target 5 mm

11 Folding Angle Distribution 30 Si U Events Events 10 3 E lab =179.0 MeV E lab =173.4 MeV E lab =167.8 MeV E lab =162.2 MeV E lab =156.5 MeV E lab =150.9 MeV E lab =145.3 MeV E lab =140.8 MeV θ fold (deg) Folding angle, fold Beam FF 1 FF 2 fold Beam FF 1 FF 2 fold Full Momentum Transfer Fission 268 Sg Nucleon-transfer Induced Fission Beam-like 238 U-like

12 Fission Fragment Mass Distributions Cross section to produce fragments (mb) Fragment Mass Quasifission K. Nishio et al., Phys. Rev. C, 77, (2008). K. Nishio et al., Phys. Rev. C, 82, (2010). Excitation Energy of CN High Incident Energy 238 U Low Incident Energy

13 Potential Energy (MeV) Dynamical calculation of nuclear shape Fluctuation dissipation model Hs CN Fission Fusion 238 U Quasifission Langevin Equation 34 S Two center shell model ( 3 dimension ) V. Zagreabev, J. Phys. G, 31, 825 (2005). Y. Aritomo et al., Nucl.Phys. A753, 152 (2005). Y. Aritomo, Phys.Rev.C, 80, (2009).

14 Shape evolution (polar collision) 30 Si U CN Y. Aritomo et al., Phys. Rev. C 85, (2012). 36 S U CN > 50 Time ( s )

15 Fusion probability Histogram All Fission Fragments Filled Area Fusion-Fission Experimental Data Fusion Probability Cross section (mb/2u) 30 Si U 34 S U 46 % 15 % 41 % 37 % 33 % 29 % 11 % 263 Sg 67 pb 7.5 % 4.9 % 264 Sg 10 pb 3.6 % c.m. Energy (MeV) 267 Hs 1.8 pb 268 Hs 0.54 pb Mass Mass K. Nishio et al., PRC 82, (2010). K. Nishio et al., PRC 82, (2010).

16 Fusion and ER cross sections 30 Si U Fission Cross section (mb) Evaporation Residue Cross section (mb) Excitation E energy Qasifission 10 pb Energy in c.m. (MeV) 34 S U Fission cross section (mb) Evaporation Residue Cross section (mb) Excitation energy Quasifission 67 pb 0.54 pb 1.8 pb Energy in c.m. (MeV) Capture Cross Section Fusion Probability Fusion Cross Section Survival Probability (Statistical Model ) Cross sections for SHN K. Nishio et al., PRC 82, (2010). K. Nishio et al., PRC 82, (2010).

17 Fission of New Region of Chart of Nuclei Appearance of a new shell in fission

18 Calculated by P. Moller (LANL) and J. Randrup (LBNL) Perspectives in Nuclear Fission, (Tokai 2012) Predicted Fission Fragment Mass Distributions 180 Hg 180 Hg * Ir 80 A. Andreyev et al., PRL, 105 (2010)

19 p Au 198 Hg* Present (E p =31.1MeV) Itkis (E p =30.0MeV)

20 Fission Q-value 300 Saddle Point Shape Q-value for Fission (MeV) Present Fm 236 U 180 Hg 193 Ir 160 Gd 124 Sn 258 Fm 238 U 193 Ir 160 Gd Fragment Mass (u)

21 Multi-nucleon transfer Induced Fission ( Surrogate Reaction ) Fission of neutron-rich nuclei Nuclear data ( Ã, Y(m), ½ )

22 Multi-nucleon Transfer Reaction 16 O 16 O 18 O 238 U 240 U * Fragment 2 Fragment 1 n 239 U ( T 1/2 =23.5m) 22

23 Experimental Setup MWPC3 MWPC1 Target 18 O Fragment 2 18 O Beam 238 U θ LAB ΔE-E ΔE = 75μm E = 300μm 240 U* Fragment 1 16 O MWPC4 MWPC2

24 Particle Identification de (MeV) 18 O U (E beam =157.5 MeV ) U Np Pu Am Pa Coincided with Fission Fragment F O N 240,239,238,237 U * n U (23.5 min) n U (6.8 day) 242,241,240,239 Np * n Np (13.9 min) n Np (65 min) n Np (2.4 day) n Np (2.1 day) E (MeV) B C 245,244,243,242,241 Pu * n Pu (4.9 hr) n Pu (14 yr)

25 235 U( 18 O, 16 O) 237 U * Fission Probability of 240 U * Events / 0.5 MeV Events / 0.5 MeV Fission Probability B f 2 nd 3 nd Excitation Energy (MeV) Spectrum for 16 O Coincidence between 16 O and fission fragments Fission Probability

26 Fission fragment mass distribution 239 Np * Preliminary Excitation energy (MeV) Yield (%) Fragment Mass (u) Fragment Mass (u)

27 Excitation Energy (MeV) 237U* 239Np* 241Pu* 238U* 239U* 240U* 240Np* 241Np* 242Np* 242Pu* 243Pu* Fragment Mass (u) 244Pu*

28 Prompt Neutron Multiplicity in Fission Pulse Shape neutron gamma Neutron Detectors (Liquid Scintilator) Pulse Height

29 Summary In beam fission experiment can be used to estimate the fusion probability for heavy-element synthesis. Using multi-nucleon transfer reactions, nuclear data can be obtained for more than 10 actinide nuclei.

30 Thank you.