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TUNL Contributions in the US Nuclear Data Program

TUNL Contributions in the US Nuclear Data Program. Nuclear Structure Data Evaluation Program J.H. Kelley (USNDP Structure Group Leader), Jim Purcell, and Grace Sheu (H.R. Weller & Kent Leung). We are responsible for nuclear structure evaluation in the A=2-20 mass region

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TUNL Contributions in the US Nuclear Data Program

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  1. TUNL Contributions in the US Nuclear Data Program Nuclear Structure Data Evaluation Program J.H. Kelley (USNDP Structure Group Leader), Jim Purcell, and Grace Sheu (H.R. Weller & Kent Leung) We are responsible for nuclear structure evaluation in the A=2-20 mass region Energy Levels of Light Nuclei reviews published in Nuclear Physics A ENSDF files for A=2-20 XUNDL from A=2-20 Web interface for A=3-20 Information

  2. Evaluation Activities • Energy Levels of Light Nuclei • Follow style of Fay Ajzenberg-Selove • Broad scope of reactions is included – discussion format. • Adopted levels/gammas, Energy Level Diagrams • ENSDF • More rigorous information required • Better documentation of original sources • reaction data sets/decay data sets • Adopted levels/gammas, decay widths, etc.

  3. Adopted Levels g-ray transitions

  4. Present Evaluation Activities Published “Energy Levels of Light Nuclei: A=3” Nucl. Phys. A848 (2010) 1 “Energy Levels of Light Nuclei: A=11” Nucl. Phys. A880 (2012) 88 (ENSDF Updated) Work in progress: • A=12 Evaluation for “Energy Levels” (90%) • Preparing A=12 ENSDF file • Preparing A=3 ENSDF file(Jim Purcell) • Preparing A=2 ENSDF file(K. Leung & H.R. Weller)

  5. Evaluation Activities • Updated ENSDF nuclides • 6B, 14F, 15Ne, 18Mg, 19Mg • Updated ENSDF Reaction Data sets • b: 14Be, 14B, 19N, 20N • b-n: 12Be, 13B, 14Be, 14B, 15B, 16C, 17B, 17C, 17N, 18C, 18N, 19B, 19C, 19N, 20C, 20N • b-p: 9C, 11Be, 13O, • b-a: 9C, 11Be, 14Be, 17N, 18N, 20Na

  6. XUNDLCompilation Activities • Experimental Unevaluated Nuclear Data Library • Up-to-date structure data Library • New articles added within 1-2 months • Feedback loop between source and evaluator • Committed to A=2-20 since April 2009 • 60-65 data sets/year (5-6/month) • Organized “Workshop on the Future of XUNDL” • TUNL May 16-17 2013

  7. Why XUNDL makes a difference 17Ne 17Ne used for device calibration

  8. Other Compilation Activities • Compilation of ground state decay & b-decay references and data • Compilation of (p,X) and (a,X) excitation functions • TUNL Dissertations- • http://www.tunl.duke.edu/~gsheu/Theses/TUNL_Theses.shtml

  9. Synergistic Experimental Activities Monoenergetic Neutron Sources at TUNLDD, DT, PT, and PLi HIGS FacilityCompton Backscattered Photons 147Nd Absolute 239Pu Fission Product Yield

  10. HIGS FacilityCompton Backscattered Photons TUNL and HIGS

  11. Nuclear Resonance Fluorescence Technique Experimental Observables in NRF • Excitation energy Ex • Spin and parity J,  • Decay width 0 • Branching ratio i/ 1- In a completely model independent way ! HIGS Advantages • σel = f(Eγ) (from primary g.s. transitions) • σinel = f(Eγ) (from secondary transitions) • σtot = σel + σinel = σabs AXN A.P. Tonchev, NIM B 241 51474(2005)‏ G. Rusev, PRC 79, 047601 (2009) TUNL and HIGS

  12. Nuclear Resonance Fluorescence Levels and Level Parameters DHS/DNDO cargo container interrogation High Intensity Gamma-ray Source

  13. Spin and Parity Determination N. Pietralla, at al. PRL 88 (2002) 012502; A. Tonchev, NIM B 241 (2005) 51474 TUNL and HIGS

  14. Spin and Parity Determination N. Pietralla, at al. PRL 88 (2002) 012502; A. Tonchev, NIM B 241 (2005) 51474 TUNL and HIGS

  15. NRF from 238U • Over 105 new excited low-spin states in 238U were observed at γ-ray beam energies from 2.0 to 5.5 MeV. • 80 E1 and 25 M1 states were identified Samantha Hammond Ph.D. Project HIGS facility is an ideal source for identifying low-spin states TUNL and HIGS

  16. NRF from 235U E = 1800 keV; ΔE/E = 70 keV m235U = 3.5 g; ti = 6 h; ϕγ = 3x107γ/s E. Kwan et al., accepted by PRC • 13 discrete deexcitations were identified for the first time in the from 1.6 to 3.0 MeV. • This includes 10 to the ground state, two branching transitions to the third excited state at 46.2 keV and one unresolved transition in 235U. • Unique decay pattern TUNL and HIGS

  17. Monoenergetic Neutron Sources available at TUNLDD, DT, PT, and PLi, Sources DENIS source FN TANDEM 10MV Shielded neutron source area Quasi-monoenergetic neutrons 7Li(p,n)7Be; Monoenergetic neutrons: 0.1 – 0.65 MeV 3H(p,n)3He; Monoenergetic neutrons: 0.5 – 7.7 MeV Flux on target (107- 108) cm-2 s-1 Energy spread dE/E = 0.1 to 0.40 2H(d,n)3He; Monoenergeticneutrons: 4.0 – 7.7 MeV 3H(d,n)4He; Monoenergetic neutrons: 14.8 – 20.5 MeV

  18. Modernizing the Fission Basis: Measurement of Fission Product Yields from Fast-Neutron-Induced Fission • Motivation • Energy Dependence of Fission-Product Yields • Experimental technique • Results • Future plans • for the LLNL-LANL-TUNL collaboration

  19. Acknowledgements • TUNL Duke • C. BHATIA • M. BHIKE • B. FALLIN • C. HOWELL • W. TORNOW N.C. State Univ. • M. GOODEN • J. KELLEY • LANL • C. ARNOLD E. BOND • T. BREDEWEG • M. FOWLER • W. MOODY • R. RUNDBERG • G. RUSEV • D. VIEIRA • J. WILHEMY LLNL J. BECKER R. HENDERSON J. KENNEALLY R. MACRI C. RYAN S. SHEETS M. STOYER A. TONCHEV 21

  20. Motivation • Resolve the long-standing difference between LLNL and LANL with respect to selected fission product data • Joint LANL/LLNL fission product review panel endorsed a possible energy dependence of 239Pu(n,f)147Nd fission product yield with fission neutrons: • 4.7%/MeV from 0.2 to 1.9 MeV (M. Chadwick) • 3.2%/MeV from 0.2 to 1.9 MeV (I. Thompson) • Mostly low energy data from critical assembly or fast reactors 239Pu(n,f)147Nd There are no 147Nd data between 1.9 and 14 MeV • Very scarce experimental data at the MeV-range • Large discrepancy (~20%) at 14 MeV M.B. Chadwick et al. Nuclear Data Sheets 111 (2010) 2923; H.D Selby et al. Nuclear Data Sheets 111 (2010) 2891. P. Baisden et al, LLNL-TR-426165, 2010; R. Henderson et al. LLNL-TR-418425-DRAFT; I. Tompson et al. Nucl. Sci. Eng. 171, 85 (2012)

  21. Fission Fragment Distribution with Neutron Energy • YiE (A) = fractional yields of mass chain ‘A’ (after b decays) from initial actinide ‘i’ for neutron energy ‘E’. • How does the asymmetry evolve with neutron energy for 235,238U, 239Pu? Depends on actinide Depends on neutron energy Goal: Develop high-precision FPY energy dependence from 1 to 15 MeV

  22. 2Hgas Monoenergetic Neutron Irradiation n-detector Dual fission chamber n p or d From VdGaccelerator One thick target ~0.2 g/cm2 Two thin targets ~10 μg/cm2

  23. Dual Fission Chamber: The Renaissance of the NIST idea gas cell FC Gas flow in and out • Design and fabricate three fission chambers: one for 239Pu, one for 235U, and one for 238U • Dedicated thin (~10 μg/cm2) 235,238U and 239Pu foils electroplated on 0.5” titanium backing★ • Dedicated thick (200 - 400 mg/cm2) 235U (93.27%) 238U (99.97%) and 239Pu (98.4%) targets • Fission chamber efficiency confirmed: 100%, confirmed with activation measurements • ★Made by LANL

  24. Fission Spectrum at En = 9.0 MeV fission alpha Excellent a / fission separation

  25. FPY Ratios to 99Mo for 239Pu at 4.6, 9.0, 14.5, and 14.8 MeV 1 J.E.Gindleret al. Phys. Rev. C 27 (1983) 2058. 2 H.D.Selbyet al. Nucl. Data Sheets 111(2010)2891-2922. 3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980. 4 T.R. England and B.F. Rider, LA-UR-94-3106. 5 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–3152 6 D.R.Nethawayand B. Mendoza, Phys. Rev. C 6 (1972) 1827

  26. FPY Ratios to 99Mo for 235U and 238U at 4.6, 9.0, and 14.5 MeV 1 L. E. Glendeninet al. Phys. Rev. C 24 (1981) 2600. 2 H. D. Selby et al. Nucl. Data Sheets 111(2010)2891-2922. 3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980. 4 W.J. Maeck et al., ENICO – 1028 (1980). 5 T.R. England and B.F. Rider, LA-UR-94-3106. 6 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–3152. 7 D. R. Nethawayand B. Mendoza, Phys. Rev. C 6 (1972) 1827.

  27. 239Pu FPY Ratios to 99Mo: at 4.6, 9.0, 14.5, and 14.8 MeVPreliminary

  28. 235U FPY Ratios with Respect to 99Mo: Comparison Preliminary

  29. 238U FPY Ratios with Respect to 99Mo: Comparison Preliminary

  30. 239Pu FPY Ratios: 147Nd/99Mo at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary

  31. 147Nd Absolute Fission Product Yield Preliminary

  32. Comparison with Theory 1. Our absolute magnitude of the 147Nd FPY below 2.5 MeV and at 14.5 MeV neutron energies are slightly higher than the predicted values. 2. We can rule out the two low-yield data at 14.8 MeV. 3. The slope of 147Nd FPY from 4.6 to 14.8 MeV is slightly negative (-1% / MeV). 4. There is no energy dependence (or it is below our experimental sensitivity) for 140Ba and 99Mo fragments. Model calculation ___ Uncertainties ___ J. Lestone. Nuclear Data Sheets 112 (2011) 3120

  33. Summary We start delivering precise(< 2% relative uncertainty) information on FPY ratios obtained at SIX energies in case of 239Pu and at FOUR energies for 235U and 238U We will deliver accurate (4-5% absolute uncertainty) information on the energy dependent fission product yields covering an energy range from 1 < En < 15 MeV Potential experiments: • Reduce 147Ndbranching ratio uncertainty from the current 8% • High-accuracy measurements in the 0-2 MeV range to clarify 144Ce and 147Nd neutron-energy dependence • Strong LLNL-LANL-TUNL Collaborative Effort

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