Coupled-Channel Computation of Direct Neutron Capture and (d,p) reactions on Non- Spherical Nuclei Goran Arbanas (ORNL) Ian J. Thompson (LLNL) with Filomena.

Slides:



Advertisements
Similar presentations
Combined evaluation of PFNS for 235 U(n th,f), 239 Pu(n th,f), 233 U(n th,f) and 252 Cf(sf) (in progress) V.G. Pronyaev Institute of Physics.
Advertisements

HIGS2 Workshop June 3-4, 2013 Nuclear Structure Studies at HI  S Henry R. Weller The HI  S Nuclear Physics Program.
Lorentzian-like models of E1 radiative strength functions V. A. Plujko, O. M. Gorbachenko, E. V. Kulich Taras Shevchenko National Kyiv University, Ukraine.
Spectroscopy at the Particle Threshold H. Lenske 1.
DNP, Hawaii 2014 Non-local potentials in nuclear reactions Luke Titus and Filomena Nunes Michigan State University.
LLNL-PRES This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.
Isospin effect in the projectile fragmentation of calcium isotopes and a possible experimental observable? Chun-Wang Ma Department of Physics, Henan Normal.
Spectroscopic factors and Asymptotic normalization coefficients Oak Ridge, Oct 2006 F.M. Nunes NSCL, Michigan State University in collaboration with D.
Lawrence Livermore National Laboratory SciDAC Reaction Theory LLNL-PRES Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA
Course Title: Nuclear Physics Course Code: EEE-202
The simplified description of dipole radiative strength function V.A. Plujko, E.V.Kulich, I.M.Kadenko, O.M.Gorbachenko Taras Shevchenko National University.
Nuclear models. Models we will consider… Independent particle shell model Look at data that motivates the model Construct a model Make and test predictions.

Higher Order Multipole Transition Effects in the Coulomb Dissociation Reactions of Halo Nuclei Dr. Rajesh Kharab Department of Physics, Kurukshetra University,
Nuclear and Radiation Physics, BAU, 1 st Semester, (Saed Dababneh). 1 Nuclear Reactions Categorization of Nuclear Reactions According to: bombarding.
25 9. Direct reactions - for example direct capture: Direct transition from initial state |a+A> to final state B +  geometrical.
Structure and Reactions of Exotic Nuclei PI32 Collaboration (theory group, but ….) Some conclusions (keywords)
The National Superconducting Cyclotron State University Betty Tsang, 2/24-26/2005 INFN Workshop on Reactions and Structure with Exotic.
(An outgrowth of our studies of shape/phase transitions and empirical signatures for them) A) An enhanced link between nuclear masses and structure B)
The Theory of Partial Fusion A theory of partial fusion is used to calculate the competition between escape (breakup) and absorption (compound-nucleus.
CHM 4444, Advanced Inorganic Chemistry. Chapters 1, Atomic structure 2, Molecular structure & bonding 3, Structures of simple solids 6, Molecular symmetry.
Nuclear and Radiation Physics, BAU, 1 st Semester, (Saed Dababneh). 1 Nuclear Binding Energy B tot (A,Z) = [ Zm H + Nm n - m(A,Z) ] c 2 B  m.
The structure of giant resonances in calcium and titanium isotopes. N.G.Goncharova, Iu.A.Skorodumina Skobelzyn Institute of Nuclear Physics, Moscow State.
XII Nuclear Physics Workshop Maria and Pierre Curie: Nuclear Structure Physics and Low-Energy Reactions, Sept , Kazimierz Dolny, Poland Self-Consistent.
Neutron transfer reactions at large internuclear distances studied with the PRISMA spectrometer and the AGATA demonstrator.
Nicolas Michel CEA / IRFU / SPhN Shell Model approach for two-proton radioactivity Nicolas Michel (CEA / IRFU / SPhN) Marek Ploszajczak (GANIL) Jimmy Rotureau.
Searching for the Low-Energy Resonances in the 12 C( 12 C,n) 23 Mg Reaction Cross Section Relevant for S-Process Nucleosynthesis Brian Bucher University.
1 New horizons for MCAS: heavier masses and α-particle scattering Juris P. Svenne, University of Manitoba, and collaborators CAP 15/6/2015.
Nuclear Level Density 1.What we know, what we do not know, and what we want to know 2.Experimental techniques to study level densities, what has been done.
HITES, June 2012 Status of reaction theory for studying rare isotopes Filomena Nunes Michigan State University.
Lawrence Livermore National Laboratory SciDAC Reaction Theory LLNL-PRES Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA
Extended optical model analyses of elastic scattering and fusion cross sections for 6, 7 Li Pb systems at near-Coulomb-barrier energies by using.
Neutral pion photoproduction and neutron radii Dan Watts, Claire Tarbert University of Edinburgh Crystal Ball and A2 collaboration at MAMI Eurotag Meeting.
Athens, July 9, 2008 The two-step  cascade method as a tool for studying  -ray strength functions Milan Krtička.
Lawrence Livermore National Laboratory Reaction Theory: Year-4 Deliverables Year-5 Plans LLNL-PRES Lawrence Livermore National Laboratory, P. O.
Chiral phase transition and chemical freeze out Chiral phase transition and chemical freeze out.
Dott. Antonio Botrugno Ph.D. course UNIVERSITY OF LECCE (ITALY) DEPARTMENT OF PHYSICS.
Accuracy of the Relativistic Distorted-Wave Approximation (RDW) A. D. Stauffer York University Toronto, Canada.
TORUS collaboration meeting, June 2012 Extracting structure information from data Filomena Nunes Michigan State University In collaboration with Anissa.
April 17 DoE review 1 Reaction Theory in UNEDF Optical Potentials from DFT models Ian Thompson*, J. Escher (LLNL) T. Kawano, M. Dupuis (LANL) G. Arbanas.
Radiochemistry Dr Nick Evans
ANC Techniques and r-matrix analysis Santa Fe, April 2008 ANC Techniques and r-matrix analysis Grigory Rogachev.
Lawrence Livermore National Laboratory Effective interactions for reaction calculations Jutta Escher, F.S. Dietrich, D. Gogny, G.P.A. Nobre, I.J. Thompson.
Interactions of Hadrons and Hadronic Showers
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh). 1 Extreme independent particle model!!! Does the core really remain inert?
Neutrino cross sections in few hundred MeV energy region Jan T. Sobczyk Institute of Theoretical Physics, University of Wrocław (in collaboration with.
Nuclear Reactors, BAU, 1st Semester, (Saed Dababneh). 1 Neutron Attenuation (revisited) Recall  t = N  t Probability per unit path length.
Reaction studies with low-energy weakly-bound beams Alessia Di Pietro INFN-Laboratori Nazionali del Sud NN 2015Alessia Di Pietro,INFN-LNS.
Lawrence Livermore National Laboratory Physical Sciences Directorate - N Division Coupled Channel Calculations 06/25/2008 Gustavo P. A. Nobre
Breakup of 22 C in a three-body model E. C. Pinilla 1, and P. Descouvemont 2 1 Universidad Nacional de Colombia, Bogotá, Colombia 2 Université Libre de.
Shape evolution of highly deformed 75 Kr and projected shell model description Yang Yingchun Shanghai Jiao Tong University Shanghai, August 24, 2009.
Fusion of light halo nuclei
Effects Of Distortion On Trojan Horse Applications Rosario Gianluca Pizzone INFN – Laboratori Nazionali del Sud Catania.
Faddeev Calculation for Neutron-Rich Nuclei Eizo Uzu (Tokyo Univ. of Science) Collaborators Masahiro Yamaguchi (RCNP) Hiroyuki Kamada (Kyusyu Inst. Tech.)
Statistical Theory of Nuclear Reactions UNEDF SciDAC Annual Meeting MSU, June 21-24, 2010 Goran Arbanas (ORNL) Kenny Roche (PNNL) Arthur Kerman (MIT/UT)
Pavel Oblozinsky NSDD’07, St. Petersburg June 11-15, 2007 ENDF/B-VII.0 Library and Use of ENSDF Pavel Oblozinsky National Nuclear Data Center Brookhaven.
Time dependent GCM+GOA method applied to the fission process ESNT janvier / 316 H. Goutte, J.-F. Berger, D. Gogny CEA/DAM Ile de France.
1 Recent Results on J/  Decays Shuangshi FANG Representing BES Collaboration Institute of High Energy Physics, CAS International Conference on QCD and.
Lawrence Livermore National Laboratory Two-Step Calculations of Nucleon-Nucleus Optical Potentials LLNL-PRES Lawrence Livermore National Laboratory,
g-ray spectroscopy of the sd-shell hypernuclei
超重原子核的结构 孙 扬 上海交通大学 合作者:清华大学 龙桂鲁, F. Al-Khudair 中国原子能研究院 陈永寿,高早春 济南,山东大学, 2008 年 9 月 20 日.
1 Cross sections of neutron reactions in S-Cl-Ar region in the s-process of nucleosynthesis C. Oprea 1, P. J. Szalanski 2, A. Ioan 1, P. M. Potlog 3 1Frank.
V. Nuclear Reactions Topics to be covered include:
Shape parameterization
Resonance and continuum in atomic nuclei
Open quantum systems.
Nuclear reaction and scattering theory
Satoshi Adachi Research Center for Nuclear Physics (RCNP),
Comprehensive study of S = -1 hyperon resonances via the coupled-channels analysis of K- p and K- d reactions Hiroyuki Kamano (KEK) YITP Workshop on.
V.V. Sargsyan, G.G. Adamian, N.V.Antonenko
Presentation transcript:

Coupled-Channel Computation of Direct Neutron Capture and (d,p) reactions on Non- Spherical Nuclei Goran Arbanas (ORNL) Ian J. Thompson (LLNL) with Filomena Nunes (MSU) Jutta Escher (LLNL) Charlotte Elster (OU) TORUS Collaboration 14 th International Conference on Nuclear Reaction Mechanisms Varenna, Italy, June 15-19, 2015

2 Presentation name Direct Neutron Radiative Capture (n,  ) Useful for studies of structure and reactions – E.g. thermal capture gamma-rays. (talk on Monday) Needed for astrophysical nucleosynthesis models – Especially for light, and neutron rich nuclei where it may be greater than compound (statistical) neutron capture – Input parameters determined from (d,p) reaction, if possible Spectroscopic Factor / Asymptotic Normalization Coeff.; binding energies,.. We compute direct (n,g) and (d,p) with consistent Coupled Channels (FRESCO) Needed for data evaluations of light and medium mass nuclei – R-matrix resonance parameter fitting for resolved resonances

3 Presentation name Direct Neutron Radiative Capture (n,  ) The effect of non-spherical shapes on direct capture has previously to this work been studied only in the incoming channels or the outgoing channels (bound states), but not in both We outline a coupled-channel approach to that self- consistently computes effects of non-spherical shape in incoming and in outgoing partitions, in DC and (d,p). We compute direct capture (and (d,p)) with and without the effect of deformation for the even calcium isotopes: Ca- 40,42,44,46,48 – By coupling 2+ and 4+, 3- states with non-zero collective strengths

4 Presentation name Schematic Coupled Channel Model Initial and final partitions couple to 2+, 4+ states n+A  +(A+1) E=0 E 2+ E 4+ Core (A) does not change state in the capture step (to be implemented). E E E1 dipole E2 quadrupole Also includes 3 - vibrational state with E3 coupling

5 Presentation name Advantages of Ca even mass isotopes Wide range of collective strengths and excitation energies Thermal capture cross sections known to better than 10%, and – Thermal neutron: measured prompt  -ray energies and branching ratios Mostly E1 capture: 82%, 93% 98% 96% 100% for Ca- 40,42,44,46,68 – Good for testing models of direct capture Mostly direct capture at the thermal neutron energy – Compound resonant capture measured but small. – Its contribution can be computed via R-matrix formalism – Small fraction of s-wave neutron E1 capture is compound resonant

6 Presentation name Model of Direct Capture Siegert’s theorem (1937): – Expresses EM operator in terms of charge density form Coupled channels (FRESCO) – I.J. Thompson, F.M. Nunes, “Nuclear Reactions for Astrophysics”, (2009) Core excitations in incoming (n+core) or outgoing (  +(n+core)) partitions: – 3-, 2+, 4+ collective states band with collective strengths from RIPL; – Core remains in the same state (0+,2+,4+,3-) during the capture step – Later we may implement core transitions in the capture step itself

7 Presentation name FRESCO Calculation Input Koning-Delaroche complex optical potential at E=0 MeV – Good for thermal neutron capture and sufficient for low-energy Deformation length parameters from RIPL database from B(E2,4) Compute direct capture and (d,p) for Ca-40,42,44,46,48 – No deformation; 2+; {2+,4}, 3- in initial and final channels – Deformation 2+; {2+,4+}; in initial channel only, or final channel only

8 Presentation name Deformation in initial vs. final states The effect of deformation in the final neutron bound state is greater than in the initial neutron scattering state – Assumed by Boison and Jang, Nucl. Phys. A189 (1972) – Using bound spectroscopic factors (SF) from Kahane et al. (1987) – Plots below are for thermal neutron capture

9 Presentation name Experimental determination of SF’s SF were determined by fitting (d,p) cross sections w/o deformation (spherical potentials) But, in bound states, the fraction of the core in its GS diminishes with coupling to 2+, 3-, 4+ core states. This upsets (d,p) fits. We compensated, approximately, by rescaling overall SF in order to make the GS component the same as was fitted before Most of the direct capture occurs into the core in the GS, so a decrease in the fraction of the core in the GS decreases capture We also (d,p) reactions with couplings to (2+, 3-, 4+) states

10 Presentation name Thermal capture results vs. data

11 Presentation name Thermal capture results vs. data

12 Presentation name (d,p) on Ca isotopes at 10 MeV (d,p) smaller for deform., but angular similar

13 Presentation name Rescaled thermal capture by (d,p) ratio This rescaling should be done for state by state

14 Presentation name Conclusions Collective-core couplings have strong effects on capture away from closed shell, and on (d,p) across the board. – Even if spherical models come close to the data Effect of non-spherical shapes are larger for final (bound) state – Bound states become fractionated among core states (0+,2+,4+,3-) – This fractionation diminishes fraction of the core in GS and direct capture To restore the original experimental spectroscopic amplitudes, renormalization of bound states will be necessary Future research Allow for core (de-)excitations in the capture step itself – Findings may yield insight on the SF renormalization method Fit (d,p) reactions with couplings to (2+, 4+, 3-) states – Extract SF/ANC from (d,p) data

15 Presentation name Renormalization of SF yields capture compatible with experiment 44Ca(n,g) spherical vs. CC (0+,2+)

16 Presentation name 44Ca(n,g) spherical vs. CC (0+,2+,4+) Renormalization of SF yields thermal capture too small

17 Presentation name 44Ca(n,g) spherical vs. CC (0+,2+,4+) Renormalization of SF yields thermal capture too small

18 Presentation name Computations of capture over-predict thermal cap. by a factor of 2 40Ca(n,g) spherical vs. CC (0+,2+)

19 Presentation name 40Ca(n,g) spherical vs. CC (0+,2+,4+) Computations of capture over-predict thermal cap. by a factor of 2

20 Presentation name DC with rescaled SF is larger than thermal capture expt. 42Ca(n,g) spherical vs. CC (0+,2+)

21 Presentation name 42Ca(n,g) spherical vs. CC (0+,2+,4+) DC with rescaled SF is larger than thermal capture expt.

22 Presentation name Renormalization of SF yields capture compatible with experiment 44Ca(n,g) spherical vs. CC (0+,2+)

23 Presentation name 44Ca(n,g) spherical vs. CC (0+,2+,4+) Renormalization of SF yields thermal capture smaller than expt.

24 Presentation name Rescaling of SF yields thermal capture larger than expt. 46Ca(n,g) spherical vs. CC (0+,2+)

25 Presentation name 46Ca(n,g) spherical vs. CC (0+,2+,4+) Rescaling of SF yields thermal capture larger than experiment

26 Presentation name All methods yield thermal capture cross sections smaller than expt. 48Ca(n,g) spherical vs. CC (0+,2+)

27 Presentation name 48Ca(n,g) spherical vs. CC (0+,2+,4+) All methods yield thermal capture cross sections smaller than expt.