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Uncertainties & Correlations in Nuclear Fission Data the Role of Models and Experiments

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Uncertainties & Correlations in Nuclear Fission Data the Role of Models and Experiments Patrick Talou Nuclear Physics Group, Theoretical Division, Los Alamos National Laboratory, USA Second International Workshop on “Perspectives for Nuclear Data for the Next Decade” Oct. 14-17, 2014, Bruyères-le-Châtel, France LA-UR-14-27975 Fission Cross Sections (n,f), (p,f), (g,f), (t,pf), etc Fission Cross Sections (n,f), (p,f), (g,f), (t,pf), etc Fission Fragment Yields Y(A,Z,KE) Fission Cross Sections Prompt Fission Neutrons (n,f), (p,f), (g,f), (t,pf), etc and Gamma Rays (multiplicity, spectrum, correlations) Fission Fragment Yields Y(A,Z,KE) Fission Cross Sections Prompt Fission Neutrons (n,f), (p,f), (g,f), (t,pf), etc and Gamma Rays (multiplicity, spectrum, correlations) Fission Fragment Yields Y(A,Z,KE) Others? b-delayed neutrons and gammas, fission fragment angular distributions, pre-scission neutrons and photons, prompt X-rays, etc. Stemming from both experiments and models Stemming from both experiments and models Some examples: . Experiments: ▪ Fission fragment yields ▪ Prompt fission neutrons . Theory: ▪ Uncertainties in modeling fission cross sections and “empirical fission barriers” ▪ Modeling the prompt fission neutron spectrum Fission Fragment Yields . Typical resolutions: ▪ 3-5 amu for Y(A) ▪ 1-2% in Kinetic Energy ▪ DZ~1 . Neutron emission from fragments ▪ Products, not fragments, are measured! . Very little data on E* dependence Fission Fragment Yields Prompt Fission Neutrons . Typical resolutions: . Multiplicity measurements (n) ▪ 3-5 amu for Y(A) ▪ Large Gd-loaded tanks ▪ 1-2% in Kinetic Energy ▪ No energy resolution ▪ DZ~1 . Spectrum (c) . Neutron emission from fragments ▪ Low-energy (<500 keV) very sensitive to ▪ Products, not fragments, are measured! multiple scattering . Very little data on E* dependence ▪ High-energy (>5 MeV) poor statistics Fission Cross Sections . Fission barrier . Double- or triple-humped . Deviations from simplified parabolas . Inertia tensor . Transition states, level densities at saddle points . Class-I,II states coupling Fission Cross Sections Prompt Fission Neutrons . Fission barrier . Simple models . Double- or triple-humped ▪ Madland-Nix, Watt, Maxwellian . Deviations from simplified parabolas ▪ Few model parameters, easy to adjust but . Inertia tensor strong correlations . Transition states, level densities at . More sophisticated saddle points ▪ Monte Carlo Weisskopf & Hauser- . Class-I,II states coupling Feshbach ▪ Many parameters, more difficult to adjust but (possibly) more faithful ▪ Various data calculated (differential) Experimental Data Chi-Nu (differential) Experimental Data Chi-Nu Theory/Modeling (differential) Experimental Data Chi-Nu Theory/Modeling Model Input Parameters ENSDF RIPL-3 … (differential) Experimental Data Chi-Nu Comparisons Theory/Modeling Model Input Parameters ENSDF RIPL-3 … (differential) Experimental Data Chi-Nu “Least-Square Comparisons Fits” Theory/Modeling Model Input Parameters ENSDF RIPL-3 … (differential) Experimental Data Chi-Nu “Least-Square Comparisons Fits” Theory/Modeling Model Input Parameters ENSDF RIPL-3 … (differential) Experimental Data Chi-Nu “Least-Square Comparisons Fits” Uncertainty Quantification Theory/Modeling Model Input Parameters ENSDF RIPL-3 … (differential) Experimental Data Chi-Nu “Least-Square Comparisons Comparisons with integral Fits” benchmarks Uncertainty Quantification Theory/Modeling Model Input Parameters ENSDF Feedback RIPL-3 … Slide 23 (differential) Experimental Data Chi-Nu “Least-Square Comparisons Comparisons with integral Fits” benchmarks Uncertainty Quantification Theory/Modeling Model Input Parameters ENSDF Feedback RIPL-3 … For fission… limited use of correlated data to constrain evaluations PFNS, sf(E*), FFAD, … Slide 24 Time-Projection Chamber Chi-Nu setup for fission cross-section (22 6Li glass detectors) to measure measurements prompt fission neutron spectra DANCE w/ NEUANCE SPIDER 2E-2v for correlated measurements on for fission fragment yield prompt fission neutrons and g measurements rays with fission fragments Many other facilities and detector setups in construction worldwide: . EAR2 at CERN . NFS @ SPIRAL2 @ GANIL . IGISOL-JYFLTRAP Time-Projection Chamber Chi-Nu setup . SOFIA: Studies On Fission with Aladin for fission cross-section (22 6Li glass detectors) to measure (reverse kinematics) at GSI measurements prompt fission neutron spectra . STEFF . … . cf. Talk by X.Ledoux DANCE w/ NEUANCE SPIDER 2E-2v for correlated measurements on for fission fragment yield prompt fission neutrons and g measurements rays with fission fragments Many other facilities and detector setups in construction worldwide: . EAR2 at CERN . NFS @ SPIRAL2 @ GANIL . IGISOL-JYFLTRAP Time-Projection Chamber Chi-Nu setup . SOFIA: Studies On Fission with Aladin for fission cross-section (22 6Li glass detectors) to measure (reverse kinematics) at GSI measurements prompt fission neutron spectra . STEFF . … . cf. Talk by X.Ledoux . New data to fill obvious gaps in our experimental database . Better accuracy DANCE w/ NEUANCE SPIDER 2E-2v . Innovative measurements for correlated measurements on for fission fragment yield . Correlated data prompt fission neutrons and g measurements rays with fission fragments . … EAR2 @ n_TOF @ CERN SOFIA: Studies on Fission with Aladin @ GSI Fission x/s measurements of actinides with half-lives ~years reverse kinematics, GSI: DA~0.6-0.8, DZ~0.4 FALSTAFF @ NFS Four Arm cLover for the STudy of Actinide Fission Fragments NFS @ SPIRAL2 @ GANIL N.Dubray, FIESTA workshop, From ascr-discovery.science.doe.gov W.Younes, FIESTA school, Sep. 10-12, 2014, Santa Fe Credit: A. Staszczak et al., ORNL Sep. 8-9, 2014, Santa Fe N.Dubray, FIESTA workshop, From ascr-discovery.science.doe.gov W.Younes, FIESTA school, Sep. 10-12, 2014, Santa Fe Credit: A. Staszczak et al., ORNL Sep. 8-9, 2014, Santa Fe Uncertainties & Errors… . Fundamental n-n force . Constrained calculations; parameter space? . Class-3 PES (N.Dubray) . Correlations s.p. and collectivity (H.Goutte) . Need for very large scale computations N.Dubray, FIESTA workshop, From ascr-discovery.science.doe.gov W.Younes, FIESTA school, Sep. 10-12, 2014, Santa Fe Credit: A. Staszczak et al., ORNL Sep. 8-9, 2014, Santa Fe Uncertainties & Errors… . Fundamental n-n force . Constrained calculations; parameter space? . Class-3 PES (N.Dubray) . Correlations s.p. and collectivity (H.Goutte) N.Schunck, . Need for very large scale computations CW2014 workshop, April 28- May 1, 2014, Santa Fe 25 224 * 225 * ) 20 Ac135 E = 11.00 (MeV) Ac136 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 226 * 217 * ) 20 Ac137 E = 11.00 (MeV) Th127 E = 13.02 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 218 * 219 * ) 20 Th128 E = 11.99 (MeV) Th129 E = 11.17 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 220 * 221 * ) 20 Th130 E = 11.00 (MeV) Th131 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 222 * 223 * ) 20 Th132 E = 11.00 (MeV) Th133 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 20 30 40 50 60 20 30 40 50 60 70 Fragment Charge Number Zf Fragment Charge Number Zf J. Randrup & P. Möller, Phys. Rev. C 88, 064606 (2013) Data from K.H.Schmidt et al., Nucl. Phys. A 665, 221 (2000) 25 224 * 225 * ) 20 Ac135 E = 11.00 (MeV) Ac136 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 226 * 217 * ) 20 Ac137 E = 11.00 (MeV) Th127 E = 13.02 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 218 * 219 * ) 20 Th128 E = 11.99 (MeV) Th129 E = 11.17 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 220 * 221 * ) 20 Th130 E = 11.00 (MeV) Th131 E = 11.00 (MeV) % ( ) f Z ( 15 A.J.Sierk, FIESTA workshop, Y d l e i Y 10 Sep. 10-12, 2014, Santa Fe e g r a h C 5 0 222 * 223 * ) 20 Th132 E = 11.00 (MeV) Th133 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 20 30 40 50 60 20 30 40 50 60 70 Fragment Charge Number Zf Fragment Charge Number Zf J. Randrup & P. Möller, Phys. Rev. C 88, 064606 (2013) Data from K.H.Schmidt et al., Nucl. Phys. A 665, 221 (2000) 25 224 * 225 * ) 20 Ac135 E = 11.00 (MeV) Ac136 E = 11.00 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 226 * 217 * ) 20 Ac137 E = 11.00 (MeV) Th127 E = 13.02 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 218 * 219 * ) 20 Th128 E = 11.99 (MeV) Th129 E = 11.17 (MeV) % ( ) f Z ( 15 Y d l e i Y 10 e g r a h C 5 0 220 * 221 * ) 20 Th130 E = 11.00 (MeV) Th131 E = 11.00 (MeV) % ( ) f Z ( 15 A.J.Sierk, FIESTA workshop, Y d l e i Y 10 Sep. 10-12, 2014, Santa Fe e g r a h C 5 0 222 * 223 * ) Th E = 11.00 (MeV) Th E = 11.00 (MeV) Uncertainties & Errors… 20 132 133 % ( ) f Z ( 15 Y d l e i Y 10 e . Macro-micro fundamental assumptions g r a h C 5 . Inertia tensor 0 20 30 40 50 60 20 30 40 50 60 70 Fragment Charge Number Zf Fragment Charge Number Zf . Temperature J. Randrup & P. Möller, Phys. Rev. C 88, 064606 (2013) . Sub-barrier fission Data from K.H.Schmidt et al., Nucl. Phys. A 665, 221 (2000) . … Monte Carlo codes to follow the de-excitation of fission fragments: CGM/F, FREYA, FIFRELIN, GEF, … 4.5 a E >.5 MeV th 4 E > 1 MeV th E > 1.5 MeV 3.5 th 3 2.5 2 1.5 (n-n) coincidences (n-n) units) (arb.
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