Caroline D. Nesaraja, Michael S. Smith

NUCLEAR DATA ACTIVITIES ATOAK RIDGE NATIONAL LABORATORY

Nuclear Structure Data

• A-chain Evaluations

Nuclear Astrophysics Data

• Evaluation and assessments of reactions & structure critical for stellar explosion studies

• Closely coupling research and data activities

NUCLEAR DATA ACTIVITIES

Online Software Systems

• Improve and expand functionality of the Computational Infrastructure for Nuclear Astrophysics

• nuclearmasses.org for the latest compiled, evaluated and theoretical masses

• Cloud Computing Initiative in Nuclear Data

(M. Martin & C. Nesaraja)

(M. Smith, C. Nesaraja et al.)

(M. Smith & E. Lingerfelt)

18F(d,n)

Nuclear Structure Data

Responsibility: Actinide Evaluations A=241 – 249 or others requested from NNDC

A=152 evaluation in progress(Murray Martin)

A=69 evaluation in progress (Caroline Nesaraja) *also for astrophysics

shown in next slide

A=121 reviewed(Murray Martin & Caroline Nesaraja)

A=125 reviewed(Murray Martin)

A=58 published in 2010(Caroline Nesaraja, Scott Geraedts, Balraj Singh)

Astrophysics Motivation: Sp(69Br) essential for studying the rp-process waiting point nucleus 68Se in X–ray burst

69Br

Waiting point nuclei: Nuclides along the rp process path that hinder or delay the abundance flow to heavier masses are called waiting point nuclei (64Ge, 68Se, 72Kr …)

Work in progress: • include in ENSDF • generate statistical model cross section for 68Se(p,g)69Br• convert to reaction rate with CINA • perform post processing element synthesis X-Ray bursts calculations with new CINA rate

Since 69Br is proton-unbound, proton capture is inhibited, and the process must wait for the long (t1/2=35.5 s) β decay of 68Se, essentially terminating the path to heavier masses.

It is possible to bypass the waiting point by sequential 2p capture through 69Br

This depends exponentially on the proton separation energy 69Br

Reaction

Reaction path near the 68Se waiting-point.

H. Schatz et al., 1998

Range of Sp where t1/2 eff is significantly below its beta decay t1/2 value

Nuclear Astrophysics Data

26SiMotivation: Properties of 26Si levels important for the 25Al(p,g)26Si reaction rate which affect the production of galactic 26Al

The 28Si(p,t)26Si*(p) Reaction and Implications for the Astrophysical 25Al(p,g)26Si Reaction Rate K.A. Chipps et al., Phys. Rev. C 82, 045803 (2010)

First measurement of proton decay branching ratios for unbound 26Si levels

24Mg25Mg

Mg*26

25Al26 g.s.Al

26S i

26 mAl

Mg26 g.s.

1.80

9-MeV

ra

y

• (d,p) transfer experiments made with radioactive 130Sn and 132Sn beams that are unique in the world

• selectively populates single-neutron states in the recoiling nucleus

131Sn ,133Sn Motivation: Provide nuclear structure information important for simulating r process nucleosynthesis in supernova explosions

Assessments of selected nuclei related to ongoing research at ORNL

NNDC-NUDAT

Nuclear Astrophysics Data

132Sn(d,p)133Sn

132Sn(d,p)133Sn results published in Nature (2010)

Online Software Systems Rate Evaluation Work Flow Tools

nuclearmasses.orgbigbangonline.org

rates

sensitivitystudies

Computational Infrastructure for Nuclear Astrophysics atnucastrodata.org

CINA runs online at nucastrodata.org, free and open to all

With a few mouse clicks, you can

• Rapidly incorporate nuclear results into stellar element burning simulations

• Run simulations and visualize results• Perform sensitivity studies to show importance of nuclear data• Share results and comments with online community

Computational Infrastructure for Nuclear Astrophysics

Frames from XRB simulation

• nuclearmasses.org launched to aid research in nuclear masses

•SHARE and ACCESS work with scientific community (experimentalist, theorist, evaluators)

• Easily VISUALIZE & ANALYZE mass datasets

• Quickly COMPARE experimental or evaluated masses to 14 theoretical mass models

• Can help facilitate future NUCLEAR MASS EVALUATIONS by providing data visualization, manipulations & comparisons to theoretical mass models

plot of the chosen reference dataset - AME2003 evaluated masses

simple analyses of datasets are possible

Nuclear Masses

CURRENT & FUTURE ACTIVITIES

Nuclear Structure/ Nuclear Astrophysics Data Evaluation and Assessments

• Mass chain evaluation A=152 & A=69 • Reaction and structure assessments for 131Sn and 27Si• Future Mass Chain Evaluation within our region of responsibility

Online Software Systems

• Computational Infrastructure for Nuclear Astrophysics - Implement a set of workflow tool for international collaboration in

Nuclear Astrophysics - Explore how work flow tools can be utilized in the broader Nuclear Data Community

• Nuclear Masses- Explore role of nuclearmasses.org in future mass evaluation efforts