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Multiplicity and Energy of Neutrons from 233 U(n th ,f) Fission Fragments

Multiplicity and Energy of Neutrons from 233 U(n th ,f) Fission Fragments. Katsuhisa NISHIO Japan Atomic Energy Agency ( JAEA ). Japan Atomic Energy Research Institute. Tokai Institute. Japan Atomic Energy Agency (JAEA), Tokai Campus. Tandem. Tokai. Tokyo. J-PARC. Contents.

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Multiplicity and Energy of Neutrons from 233 U(n th ,f) Fission Fragments

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  1. Multiplicity and Energy of Neutrons from 233U(nth,f) Fission Fragments Katsuhisa NISHIO Japan Atomic Energy Agency (JAEA)

  2. Japan Atomic Energy Research Institute Tokai Institute Japan Atomic Energy Agency (JAEA), Tokai Campus • Tandem Tokai Tokyo J-PARC

  3. Contents • Neutron multiplicity and energy spectrum measurement • ➢ 235U(nth,f),233U(nth,f),239Pu(nth,f) • (2) Experiment at J-PARC • ➢ n+actinide • ➢ μー + actinide Research Reactor, Kyoto University

  4. Contents • Neutron multiplicity and energy spectrum measurement • ➢ 235U(nth,f),233U(nth,f),239Pu(nth,f) • (2) Experiment at J-PARC • ➢ n+actinide • ➢ μー + actinide

  5. Research Reactor Institute, Kyoto University Tokai Kyoto Tokyo Osaka Supermirror Neutron Guide Tube 5×107 neutrons/cm2/s Kyoto University Reactor 1964 First Criticality 5 MW Operation

  6. Fission Neutron Measurement at KURRI Fission Fragment ( mass and kinetic energy ) ➢　Si-detector : Pulse height Analysis ➢ Parallel Plate Avalanche Counter : Time-of-Flight analysis Prompt Fission Neutron (neutron energy) 　➢　Flight path = 76.5 cm 　　➢　Liquid Scintillator NE213 ( Φ 5 ” × 2 ”) K. Nishio et al., J. Nucl.Sci.Technol., 35, 631 (1998).

  7. Neutron Spectra FWHM = 1.5 ns For neutrons energy Spectra in the c.m. Frame ➢ Vn >= Vf1 / cos θ Assumption : All the neutrons are emitted from the fully accelerated fragments

  8. Calculated Neutron yields Light Fragment Heavy Fragment Fragment 1 Fragment 2 Neutron detector θ < 18o

  9. Fission Fragment Yield

  10. Neutron energy spectra from fragments in c.m. frame for 233U(nth,f)

  11. Average neutron energy from FFs for 233U(nth,f)

  12. Neutron multiplicities for 233U(nth,f) νＬ ＝1.49 νH = 1.01

  13. Total Neutron multiplicity as function of TKE for 233U(nth,f)

  14. Neutron multiplicity from fragment as function of TKE for 233U(nth,f)

  15. Scission configuration

  16. Level density parameters of fission fragments

  17. Total excitation energy of the fragments

  18. Total neutron multiplicity for each TKE TKE (MeV)

  19. Contents • Neutron multiplicity and energy spectrum measurement • ➢ 235U(nth,f), 233U(nth,f),239Pu(nth,f) • (2) Experiment at J-PARC • ➢ n+actinide • ➢ μー + actinide

  20. J – PARC (Japan Proton Accelerator Research Complex )

  21. 3 GeV Linac Hadron Experimental Hall Neutrino Target Area Materials & Life Experimental Hall Materials & Life Experimental Hall

  22. J－PARC Now 100 kW (300 kW) Current (μA) Energy (GeV)

  23. MLF Materials and Life Science Facility Shutter on the Top of the Source Mercury Target and Its Container MLF Building Proton Beam

  24. MLF Materials and Life Science Facility Neutron Beam Lines Summer of 2007

  25. MLF Materials and Life Science Facility Neutron Time-of-flight cource Proton

  26. Neutron TOF course Flight path = 22 - 29 m Neutron energy = 0.01 eV – 100 keV Undergoing measurement ➜ Neutron capture cross-sections for 244,245Cm, 129I, 99Tc, 93Zr ➜ Fission experiments can be proposed !

  27. Neutron induced Fission ➢　Prompt neutron multiplicity and energy spectra Mass – TKE correlations (Cm244,Cm245, …) Pre-scission neutron ? I. Tsekhanovich et al., Phys.Rev.C 70 , 044610 (2004)

  28. Investigation for the Fission Neutrons Target Prompt Fisssion Neutron Neutron form J-PARC Fragment Neutron Detectors Fission Fragment Detectors Energy of prescission neutron ?

  29. Neutron induced Fission ➢　Fragment mass distribution and angular distributions from each resonances. ➢ Resonance tunneling through the collective states in the 2nd minimum ( mass distributions )

  30. Contents • Neutron multiplicity and energy spectrum measurement • ➢ 235U(nth,f), 233U(nth,f),239Pu(nth,f) • (2) Experiment at J-PARC • ➢ n+actinide • ➢ μー + actinide

  31. muon course 3 GeV proton • Positive or negative muons slower than 120 MeV/c are available. • Beam intensity（＠100kW proton beam): 1.0×106/s

  32. μ－ induced Fission V.E. Oberacker et al., Phys.Rev.C 48, 1297 (1993). E1(2p->1s) 238U = 6.6 MeV E2(3d ->1s) 238U = 9.6 MeV Delayed Fission (78 ns in238U) Prompt Fission : muon stays at the fissioning nucleus H L 3d 2p 1s ?

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