Lawrence Livermore National Laboratory

Reaction Theory:Year-4 Deliverables

Year-5 Plans

LLNL-PRES-436792

Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94551

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Ian Thompson

2LLNL-PRES-436792 UNEDF Meeting, June 2010

Lawrence Livermore National Laboratory

Promised Year-4 Deliverables

Fold QRPA transition densities, with exchange terms, for systematic neutron-nucleus scattering.

Derive optical potentials using parallel coupled-channel reaction code capable of handling 105 linear equations

Use CCh channel wave functions for direct and semi-direct (n,) capture processes.

Consistently include multi-step transfer contributions via deuteron channels and implement and benchmark the two-step method to generate non-local optical potentials.

Extend and apply KKM model to scattering with doorway states.

3LLNL-PRES-436792 UNEDF Meeting, June 2010

Lawrence Livermore National Laboratory

Delivered in Year-4

For a range of nuclei A ~ 40 – 144:• calculated QRPA transition densities,• performed systematic CCh calculations for all open inelastic & transfer channels. • Letter submitted, and a longer paper begun.  • Infrastructure for non-local potentials is being developed.

Combinations of MPI and OPENMP parallelisms for coupled channels solutions have been developed and tested.

Enable solutions of 20000 coupled channels, the largest that has been required from the QRPA models. • Included transfer effects via deuteron channels, • successfully benchmarked two-step methods that generate explicit non-local optical

potentials. • Local equivalent potentials are now being generated.

CCh entrance channel wave functions used for (n,) capture processes, • Comparing off-shell effects of local vs nonlocal entrance potentials.

Plans underway to implement energy-dependence of eigensolutions in the expansion for the KKM theory.

4LLNL-PRES-436792 UNEDF Meeting, June 2010

Lawrence Livermore National Laboratory

Further Research on Optical Potentials

1. Compare coupled-channels cross sections with data

2. Reexamine treatment of low partial waves: improve fit?

3. Effect of different mean-field calculations from UNEDF.

4. Improve effective interactions:• Spin-orbit parts spin-orbit part of optical potential• Exchange terms in effective interaction small nonlocality.• Density dependence (improve central depth).

5. Examine effect of new optical potentials:• Are non-localities important?• Is L-dependence significant?

6. Use also ab-initio deuteron potential.

7. Do all this for deformed nuclei (Chapel Hill is developing a deformed-QRPA code)

5LLNL-PRES-436792 UNEDF Meeting, June 2010

Lawrence Livermore National Laboratory

Year-5 Plans

Consistent optical potentials in inelastic & transfer channels Fold QRPA transition densities with density dependent and spin-

orbit forces. Include effective masses, and direct charge-exchange. (Nobre, Escher)

Calculate & find effects of exchange nonlocalities. (Nobre, Escher, Thompson)

Examine role of optical-potential L-dependences & non-localities in direct reaction calculations. (Nobre, Thompson)

Systematic generation of optical potentials for a wide range of near-spherical nuclei. (Nobre, Arbanas)

Examine energy-dependence of eigensolutions in the expansion for the KKM theory. (Arbanas)

First calculations with deformed QRPA transitions.