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DN Yields & Time Spectra from p(1 GeV) + 238 U

DN Yields & Time Spectra from p(1 GeV) + 238 U. Chaos in… my presentation but not in physics I will be talking about!. Photons. ELSA. Energy (eV). data for non-destructive interrogation with photons. PhotoNuc: experiment. waste characterization & material detection on borders.

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DN Yields & Time Spectra from p(1 GeV) + 238 U

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  1. DN Yields & Time Spectra from p(1 GeV) + 238U Chaos in… my presentation but not in physics I will be talking about! Contact: ridikas@cea.fr

  2. Photons ELSA Energy (eV) • data for non-destructive interrogation with photons PhotoNuc: experiment waste characterization & material detection on borders Delayed neutron & delayed photon measurements 6 groups of {ai, i} He-3 Targets:232Th, 235,238U, 237Np, 239Pu Collaboration Experiments: CEA/DAM+DRT+DEN, Geel BGO D. Doré et al. Contact: ridikas@cea.fr

  3. Photons Energy (eV) PhotoNuc: modeling • Contribution of DAPNIA: • 6 major actinide evaluations  ENDF-B/VII • future evaluations for JEFF will include •  extension up to 130 MeV •  fission fragment distributions •  delayed neutron data E. Van Lauwe et al. Collaboration Modeling: LANL, GSI, NRG E. Dupont et al. Contact: ridikas@cea.fr

  4. Photons ELSA Energy (eV) PhotoNuc: experiment • Improvement of the old data: 238U,232Th, 235U • Provision of new measurements: 237Np, 239Pu V. Macary et al. 1 2 3 4 5 6  DN energy dependence similar to n-fission  2nd chance fission  ABLA contains the experimental trend M.L. Giacri, A. Van Lauwe et al. Contact: ridikas@cea.fr

  5. Photons ELSA Energy (eV) Isotopic identification: Use of delayed neutrons PhotoNuc Use of the new parameterization for uranium enrichment determination from DN decay curves Imix(t) = mU YU(t) + mTh YTh(t) New parameters Experiment Old parameters 238U DN activity 232Th New parameters • impact of the new high precision parameterization! Time (s) D. Doré et al. Contact: ridikas@cea.fr

  6. Photons ELSA Energy (eV) Delayed Photons  No available data  DP/fission ~ 10* DN/fission  DP low sensibility to H content  DP/DN  promising INPHO Experiments  Elsa  2 BGO detectors, 5 actinides  Analysis based on ABLA model  {Ai,Ti1/2} groups for the 1st time P. Dighe, E. Berthoumieux et al. Contact: ridikas@cea.fr

  7. From photofission to “satellite” projects on DN studies DN Yields & Time Spectra from p(1 GeV) + natFe, natPb, 209Bi, 238U Contact: ridikas@cea.fr

  8. Examples (A) J-PARK/JAEA - thanks to H. Nakashima Delayed neutrons Prompt neutrons • short Hg transit time  delayed neutron (DN) activity Contact: ridikas@cea.fr

  9. Examples (B) MegaPie/PSI - thanks to F. Groeschel DN/PN = ? Successful operation for 4 months in 2006! ~5.3 m DN and PN estimates using MCNPX+CINDER’90 Φn (DN)~ 106 n/(s cm2) Φn (PN)~ 106 n/(s cm2) Important: DN yields are very sensitive to the choice of physics models and no data were found! D. Ridikas et al., Proc. of PHYSOR2006, Vancouver, Canada. Contact: ridikas@cea.fr

  10. DN measurements from p (1GeV)+Pb at PNPI Gatchina (Russia) PNPI synchrocyclotron Contact: ridikas@cea.fr

  11. Experimental strategy • He-3 counter calibration: • 252Cf neutron source + Monte Carlo • Proton beam monitoring: • 27Al foils and gamma spectroscopy from 22Na, 24Na and 7Be • Measurement strategy: • No target at all – long irradiations • Concrete block – long irradiation • Iron thick target – long irradiations • Lead target of variable thickness; • short (350 s), intermediate (20 s) and long (300 s) irradiations Contact: ridikas@cea.fr

  12. Proton beam monitoring Beam size/profile: by photo-films at exit and entrance positions Beam intensity: by 27Al foils and gamma spectroscopy from 22Na, 24Na and 7Be Photo-films 1GeV protons Al foils • 27Al(p,x)7Be monitor reaction cross section7.5  0.3 mb was taken as a reference • ratios of 24Na &22Na with respect to 7Be were equal to 1.73  0.15 & 1.99  0.07 •  uncertainty in proton beam monitoring from 8 % to 12 % Contact: ridikas@cea.fr

  13. DN decay curve: p + natPb (55 cm) • “Understandable” from x-sections • p(1GeV)+Pb  9Li ~ 1000 b • p(1GeV)+Pb  17N ~ 600 b • p(1GeV)+Pb  87Br ~ 33 b D. Ridikas et al., EPJA 32 (2007) Contact: ridikas@cea.fr

  14. Why only 4 exponentials are sufficient? Production of Br isotopes T1/2 (s) 55.6 16.0 4.4 1.8 0.18 U fission Pb fission; low energy  high energy Contact: ridikas@cea.fr

  15. Reproduced with 4 major contributions : 9Li, 17N,88Br, and 87Br DN decay curves: p + natPb, 209Bi A. Prévost et al. Contact: ridikas@cea.fr

  16. The same 4 major contributions : 9Li, 17N,88Br, and 87Br DN decay curves: p + 209Bi A. Prévost et al. Contact: ridikas@cea.fr

  17. Experimental precursor yields (atoms/proton) 17N 87Br 88Br 17N • Saturation seems observed • for targets thicker than 20 cm • Similar shapes and absolute values both for Pb and Bi 87Br 88Br Contact: ridikas@cea.fr

  18. INC (JAM) + EVAP(GEM) JAM: Jet AA Microscopic Transport Model GEM: Generalized Evaporation Model H. Iwase, K. Niita, T. Nakamura, Journal of Nuclear Science & Technology 39 (2002) 1142. Precursor yields: data versus PHITS simulations Pb 17N 87Br 88Br  Predictions within a factor of 2! V. Blideanu et al. Contact: ridikas@cea.fr

  19. Physics: ratios of relative yields relative to 87Br Experiment stable decreasing  Produced by different reaction mechanisms Confirmed by PHITS predictions V. Blideanu et al. Contact: ridikas@cea.fr

  20. Extraction of x-sections : 17N & 87,88Br Using thin targets  Good agreement with old data and/or systematics! D. Ridikas et al., EPJA 32 (2007) Contact: ridikas@cea.fr

  21. Absolute DN production yields: consequences Assumption: p(1GeV) + Pb (55 cm thick; 10 cm ) at 1mA (1 MW) • Important data for: • SNS based on liquid metal targets • ToF facilities (DNs background neutrons) Contact: ridikas@cea.fr

  22. Conclusions and outlook • importance of DN in liquid metal high-power targets for radioprotection issues • importance of the measurements to test model calculations • DN yields and time spectra measured for the 1st time for p(1GeV) on thick natPb and Bi targets • Estimates of errors on DN decay curves : below 20 % • Major contributors are: 87Br, 88Br and 17N  extraction of x-sections • PHITS code “recommended” for such studies • Consequences and “in-situ” experiment… Contact: ridikas@cea.fr

  23. CEA/DSM/DAPNIA’s contribution for MegaPie S. Panebianco et al. ~2-3m 3He  Delayed neutrons  Prompt neutrons A. Letourneau et al. Contact: ridikas@cea.fr

  24. … and if one comes back to physics Contact: ridikas@cea.fr

  25. DN yield as a function of incident neutron energy p(1GeV) + 238U in Nov. 2007 What is beyond 20 MeV? Thanks to P. Romain et al. CEA/DIF/DPTA Contact: ridikas@cea.fr

  26. Production of Br isotopes: dependence on energy T1/2 (s) 55.6 16.0 4.4 1.8 0.18 U fission Pb fission; low energy  high energy Contact: ridikas@cea.fr

  27. p(1GeV)+U GSI data: inverse kinematics Production of 87Br ~3.8 mb * 0.025 0.095 Dostrovsky et al.: from DN curves Nearly a factor of 2! No change with energy? Contact: ridikas@cea.fr

  28. Modeling of DNs in 3 steps: p(1GeV)+238U 2) Summation of Y(A,Z)*Pn according to T1/2 1) INCL4+ABLA for Y(A,Z) ----------Group 2------------------ Y*Pn, *10e6 T1/2,s Ba144 g - 9.26051 - 11.500 Br88 g - 25.1614 - 16.290 Te136 g - 1.62791 - 17.630 I137 g - 28.16053 - 24.500 Cs141 g - 0.21140 - 24.940 Total: 64.42184 <T1/2>: 19.25251 3) Construction of DN tables T1/2, s Yn*Pn, x 106 g1: 55.598 13.83926 g2: 19.252 64.42184 g3: 4.975 48.61182 g4: 2.051 124.89912 g5: 0.450 38.10098 g6: 0.197 12.99792 <T1/2>=9.397 Total: 303.3795 Contact: ridikas@cea.fr

  29. Photo of the experimental setup: p(1GeV)+238U Nov. 2007 PNPI Gatchina Al foil 238U + Al foil • 0.3mm, 1cm & 2cm thick 238U targets • 3cm x 3cm Contact: ridikas@cea.fr

  30. “Raw” experimental data: p(1GeV)+ 238U  DNs signal • 1 bunch – 2 s; channel=5ms • 20 s – 100 s; channel=0.2s • 300 s – 300 s; channel = 0.2s signal background background “background”  empty Al envelope Contact: ridikas@cea.fr

  31. “Raw” data versus modeling T1/2, s ai, x 106 g1: 55.598 13.83926 g2: 19.252 64.42184 g3: 4.975 48.61182 g4: 2.051 124.89912 g5: 0.450 38.10098 g6: 0.197 12.99792 + g8 (N17): 4.173s ~450 g9 (Li9): 0.178s ~2500 T1/2, s Yn*Pn, x 106 g1: 55.598 13.83926 g2: 19.252 64.42184 g3: 4.975 48.61182 g4: 2.051 124.89912 g5: 0.450 38.10098 g6: 0.197 12.99792 <T1/2>=9.397 Total: 303.3795 Contact: ridikas@cea.fr

  32. From the DN decay curve: p (1GeV)+ U Short lived fragmentation products dominate over longed lived fission products (?!) • “Understandable” from x-sections • p(1GeV)+U p(1GeV)+Pb • in ( * Pn) due to production of • 9Li ~1.7 mb * 0.510 0.87 0.51 • 17N ~1.1 mb * 0.950 1.05 0.57 • 87Br ~3.8 mb * 0.025 0.10 0.0008 • 88Br ~2.9 mb * 0.066 0.19 0.0009 Detailed analysis in progress as a part of PhD thesis by G. Stankunas Contact: ridikas@cea.fr

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