Caroline Nesaraja, Michael Smith, Daniel Bardayan, Jeffery Blackmon, Eric Lingerfelt, Jason Scott, W. Raphael HixPhysics Division, Oak Ridge National Laboratory

Kyungyuk Chae, Zhanwen Ma, Michael GuidryDepartment of Physics & Astronomy, University of Tennessee

Chase Hard, Raymond Kozub, Jacob SharpDepartment of Physics, Tennessee Technological University

Jeffry ThomasDepartment of Physics & Astronomy, Rutgers University

R. A. Meyer RAME, Inc.

NUCLEAR DATA ACTIVITIES FOR ASTROPHYSICS AT

OAK RIDGE NATIONAL LABORATORY

Overview

• Nuclear data for unstable nuclei – crucial for stellar explosion studies.

• Holifield Radioactive Ion Beam Facility (HRIBF) at ORNL

– provides opportunity to study reactions involving unstable nuclei.

• Evaluations at ORNL – tightly coupled to measurements of nuclear reactions &

structure information relevant to nuclear astrophysics

• Computational Infrastructure for Management & Visualization of Nuclear Astrophysics Data

– process nuclear data into formats used in nuclear astrophysics simulations

Experiments at HRIBF, ORNL

Analysis of experimental data –properties of excited states (spin, parity, total & partial decay widths, energy, spectroscopic factor); cross sections

Data evaluations related tothe measurements at HRIBF - analysis of all literature on the nuclei of interest - determine ‘best values”

LABORATORY

STARSProcessing and disseminatingdata for astrophysics simulations.www.nucastrodata.org

Motivation

• Proton capture reactions on proton-rich unstable nuclei (rp process)• Structure & reaction information is needed to understand nova explosion and X-ray burst

• Neutron capture reactions on neutron-rich unstable nuclei (r process)• Information is needed to simulate supernova explosions

Nuclear Structure Data• A= 241- 249 actinide region – Murray Martin

Nuclear Astrophysics Data • Evaluation of Reactions critical for Stellar Explosions

• Development of Computational Infrastructure for Nuclear Astrophysics Data

Nuclear Data Activities

Nuclear Astrophysics Data

Structure & Reaction Evaluations

14O(p)17F

• Important transition reaction between the hot CNO cycle to the rp process

• Multi-level R-matrix analysis is being performed on the 17F(p,)14O, 17F(p,p)14Fgs, & 17F(p,p1)14F*

495

differential cross sections

• “Best Values” of properties for levels in 18Ne will then be used todetermine new reaction rates

J.C. Blackmon, 2001

18F(p,)17F & 18F(p, )19Ne

• important for understanding production of the observable radioisotope 18F in novae & the heavy element production in X-ray burst .

re- evaluation in progress

• Low temperature rate better defined with 18F(d,p) measurement • new spectroscopic factors assigned to low energy resonances

Kozub 2004

• High temperature rate better defined with 18F(p,p) measurement • upper limit set on 19Neresonant contributions, new resonance found

D.W.Bardayan, 2004

• 19Ne - 19F analog assignments revised based on R-matrix analysis of old 15N(,) data • changes rate at nova temperatures

15N(,) analysis

upper limit set

w/o broadresonance

D.W.Bardayan, 2004

R.L Kozub, 2004

18F(d,p)19F

82Ge(d,p)83Ge

• First neutron transfer reaction measurement on a nucleus in the r-process path• Structure information important for studies of neutron capture rates in the astrophysical r-process.

J.S. Thomas , 2004

J.S. Thomas – Single –neutron excitations in neutron- rich N=51 isotones –SESAPS 2004

Computational Infrastructure

User friendly, platform independent software tools to process nuclear data into astrophysics models

Available online at

nucastrodata.org

Prior to the development of our Computational Infrastructure, there has been no easy, user friendly, uniform, reliable way to get most recent nuclear results into astrophysical models

Computational Infrastructure Components

• Rate Generator

• Rate Manager

• Rate Library Manager

• Nuclear Data Evaluator’s Toolkit

• Nuclear Data Manager

• Nuclear Data Viewer

• Element Synthesis Simulator

• Element Synthesis Manager

• Element Synthesis Visualizer

Nuclear Data

Reaction Rates & Rate Libraries

Element Synthesis

Prior to the development of the Computational Infrastructure Suite, the entire process used to rely on numerous people and could take years, now it is done in minutes to an hour

Future Work

• Evaluation work on 29P(p, )30S30P(p, )31S33Cl(p, )34Ar34Cl(p, )35Ar

• Murray Martin will be training me further to do evaluations

• Expand functionality of the Computational Infrastructure - adding new features

- modules may be useful in other areas of nuclear science

• Information on unstable nuclei is important for stellar explosion studies

• Radioactive beam facilities play a crucial role in obtaining this information

• The information has to be evaluated, processed and distributed in order to be used in astrophysics simulation

Nuclear Astrophysics Data Program at ORNL

• Nuclear data evaluation activities at ORNL closely coupled to nuclear astrophysics measurements at HRIBF

• New Computational Infrastructure with unique software tools hosted

at nucastrodata.org – suite of codes for astrophysical related calculations, data management and data visualization

Summary