1 / 23

Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms

EFF-DOC-893. Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms. 1 EURATOM-MEC Fusion Association, “Horia Hulubei” National Institute for Physics & Nuclear Engineering, P.O Box MG-6, 76900 Bucharest, Romania

zazu
Download Presentation

Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EFF-DOC-893 Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms • 1EURATOM-MEC Fusion Association, “Horia Hulubei” National Institute for Physics & • Nuclear Engineering, P.O Box MG-6, 76900 Bucharest, Romania • 2EURATOM-FZK/TUD Fusion Association, Technische Universität Dresden, D-01062 • Dresden, Germany • 3EURATOM-UKAEA Fusion Association, Culham Science Center, Abingdon OX143DB, • United Kingdom • 4Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 • 5Nuclear Research and Consultancy Group NRG, P.O. Box 25, 1755 ZG Petten, • The Netherlands V. Avrigeanu1, R. Eichin2, R.A. Forrest3, H. Freiesleben2, M. Herman4, A.J. Koning5, and K. Seidel2 EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  2. Outline [e.g.1, EFF-DOC-872, Nov. 2003] • Nuclear cross sections calculations • Search for appropriate optical model potentials: n+182,183,184,186W • p+ 181Ta • Compilation of the available experimental data (E<20 MeV) • Nuclear model calculations (E<20 MeV) • Comparison with all activation experimental data • Processing of model calculations results • Cross sections of all individual channels with activation data • [Benchmark experiment analysis updating • calculated-to-experimental (C/E) activity: reduced deviation from unity ] 1P. Pereslavtsev and U. Fischer, Evaluation of n+184W cross-section data for EFF up to 150 MeV EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  3. Flowchart of model calculations • EMPIRE-II v.2.18 [ECIS95/SCAT2, DEGAS, MSD-TUL/MSC-H, HF] • st, sR, sCC, sabs - Tl(E) neutron deformed optical potential- p-, a- spherical optical potentials - EMPIRE-specific level density, Nmax< 40 - DEGAS [g=A/13 MeV-1, K=100 MeV3] • STAPRE-H v.2002 [SCAT2, GDH, HF]- p-, a- spherical optical potentials - BSFG, E*<Bn: (a,D) D0-, Nmax-fit a(E*), E*>Bn: Junghans/Koning/Chadwick I/Ir: 0.5(g.s.)-0.75(Bn)-1(15 MeV) - GDH [ gFGM(e), AK(p,h), fK(p,h,E,F1(l,Ei)) ] • TALYS-0.58 [Koning and Duijvestijn] EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  4. Optical model potentials • Neutrons (n+182,183,184,186W):SPRT analysis (SPR added in EMPIRE-II output) • P.G. Young+ (1990) [as RIPL-2 in EMPIRE-II] (local) • J.P. Delaroche, as in NEANDC-253”U”, OECD/NEA-DB, 1989 (local) • P.G. Young, NEANDC-222”U”, OECD/NEA-DB, 1986 (global: II.B) • P.G. Young+ (1990) - modified (local) • RIPL-2/P.G. Young+ (1986) - modified (local) • Protons (p+181Ta) • R.L. Walter and P.P. Guss, Rad. Effects 92, 1079 (1986) (global) • N. Yamamuro, NDST-1988, Mito, Japan, p.489 (global) • Walter-Guss (1986) - modified (local) • Alphas • V. Avrigeanu, P.E. Hodgson, M. Avrigeanu, Phys.Rev.C 49,2137(1994) (global) EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  5. Optical model parameters used to describe the scattering of neutrons on W isotopes, and the corresponding absorption cross section for the element W at the incident neutron energy E=14.1 MeV EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  6. Comparison of experimental and calculated neutron scattering parameters of 182,184,186W EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  7. Comparison of calculated and experimental neutron total cross sections for 182,183,184,186W isotopes with emphasis of the lower energy region EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  8. Comparison of calculated and experimental neutron total cross sections for 182,183,184,186W isotopes EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  9. Comparison of neutron total cross sections for 182,183,184,186W isotopes calculated by using presently modified OMPs EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  10. Comparison of the calculated and measured proton reaction cross sections and (p,n) reaction cross sections for 181Ta Walter-Guss (1986) - modified (local): WD=10.48-0.250E+14.94h, E<10 MeV 9.55-0.157E+14.94h, E>10 MeV aD= 0.742-0.0115E, E<20 MeV 0.512, E>20 MeV EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  11. Nuclear Level Density Cumulative number of levels against excitation energy for, e.g.,178,179Hf, and corresponding prediction of the BSFG model EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  12. The g-ray strength functions • Modified energy-dependent Breit-Wigner (EDBW) model28,29: fE1(Eg) • Comparison of experimental20,30 and the calculated average radiative widths • Gg0 (meV) used for normalization of fE1(Eg) capture data description 20A.V. Ignatyuk, at http://161.5.7.5/RIPL-2/resonances/ . 28D.G. Gardner and F.S. Dietrich, Report UCRL-82998, LLNL-Livermore, 1979. 29M. Avrigeanu, V. Avrigeanu, G. Cata, and M. Ivascu, Rev. Roum. Phys. 32, 837 (1987). 30R.L. Macklin, D.M. Drake, and E.D. Arthur, Nucl. Sci. Eng. 89, 98 (1983). EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  13. Comparison of calculated and measured neutron capture cross sections of 180,182-184,186W isotopes EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  14. Sample case of isomeric state populated by side- and continuum-decay cascade-feeding [http://tandem.nipne.ro/~vavrig/Publications/2003/papmo_1z.ps] EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  15. Comparison of the measured and calculatedreaction cross sections for the target nucleus 180W Calculated values by means of the computer codes EMPIRE-II and TALYS with default global parameters (except the local OMPs) and STAPRE-H with local parameter set given in this work. EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  16. Comparison of the measured and calculatedreaction cross sections for the target nucleus 182W Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+ (1980). EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  17. Comparison of the measured and calculatedreaction cross sections for the target nucleus 183W Calculated values by means of the computer codes EMPIRE-II and TALYS with default global parameters (except the local OMPs) and STAPRE-H with local parameter set given in this work. EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  18. Comparison of the measured and calculatedreaction cross sections for the target nucleus 184W Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+ (1980). EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  19. Comparison of the measured and calculatedreaction cross sections for the target nucleus 186W Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+ (1980). EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  20. Sensitivity of calculated (n,2n)reaction cross sections vs. reaction mechanisms & model parameters Calculations with EMPIRE-II and default global parameters excepting local OMPs. A normalization factor of 1.078 (Vonach+, 1990) was applied to data of Frehaut+ (1980). EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  21. Sensitivity of calculated (n,p)reaction cross sections vs. reaction mechanisms & model parameters Calculations with EMPIRE-II and default global parameters excepting local OMPs. EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  22. Sensitivity of calculated (n,p)reaction cross sections vs. reaction mechanism codes Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

  23. Conclusions • Achievements • Appropriate optical model potentials: n+182,183,184,186W • Unitary description of all activation experimental data (E<20 MeV) by using a local parameter set in STAPRE-H code • Good results of blind calculations and global parameters within EMPIRE-II and TALYS codes • Similar sensitivity of calculations vs. reaction mechanisms & model parameters • Problems • Major uncertainty of calculated isomeric cross sections: level schemes & branching ratios • (n,p)-, (n,a)-reaction excitation functions at En>15 MeV • Completion • Similar analysis for: n+180,181Ta, n+174,176,177,178,179,180Hf • Need for (n,p)-, (n,a)-reaction data at En>15 MeV (e.g., JRC/IRMM) EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

More Related