Decay Spectroscopy Working GroupNuclear Structure Theory

Morten Hjorth-Jensen – Shell Structure and InteractionsIvan Borzov – Theory of b Decay

Applications of Nuclear Decay DataHendrik Schatz – Nuclear Astrophysics (r-process)Ian Gauld – Nuclear Reactors, Safeguards, and National Security

Key Nuclear Structure Experiments and Equipment at Upgraded HRIBF78Ni Region: Chiara Mazzocchi132Sn Region: Agnieszka Korgul and Jon BatchelderNuclear Level Lifetimes: Volker Werner and Henryk MachProton drip-line and SHE studies with SIBs and RIBs – Robert PageNeutron Detection: Miguel MadurgaElectron Counting: Ed ZganjarTotal Absorption Gamma Spectroscopy: Marek KarnyHigh Resolution and Efficiency Gamma Counting: Sean LiddickHigh Resolution Isobar/Isomer Separator: Andreas PiechaczekStorage Ring: Robert Grzywacz

Nuclear Shell Structure and Interactions – M. Hjorth-Jensen

48Ni – 56Ni – 68Ni – 78Ni

100Sn – 114Sn – 116Sn – 132Sn – 140Sn

Experimental Benchmark for many-body forces

Deformation: Density Functional Theory

Theory of b Decay – I. Borzov

I.N. Borzov, PRC 71(2005)065801

C70 Reach

I.N. Borzov, NPA777(2006)645

J.A. Winger et al., PRL 102 (2009) 142502

Nuclear Astrophysics – H. Schatz

“… our current simulation is far from reproducing the solar r-process signature. […] One reason for this could well be the uncertainties in the -decay rates.” (Fryer et al. 2006)

“… our current simulation is far from reproducing the solar r-process signature. […] One reason for this could well be the uncertainties in the -decay rates.” (Fryer et al. 2006)

--> Great opportunities at upgraded ORNL ISOL facility for a major step in probing (and understanding) the r-process

Reach the point where the models can no longer blame nuclear physics for the inability to get the correct result.

Nuclear Reactors, Nuclear Safeguards, and National Security – I. Gauld

OECD/NEA WPEC 25 Decay Heat Analysis

• International Working Party on Evaluation Co-operation of the NEA Nuclear Science Committee NEA/WPEC-25

• VOLUME 25 - Assessment of Fission Product Decay Data for Decay Heat Calculations http://www.nea.fr/html/science/wpec/volume25/volume25.pdf

• Important to – – Reactor LOCA analysis

– Delayed gamma analysis from active neutron interrogation

• Known issues with evaluations• WPEC-25 developed a priority list

of isotopes for re-measurement

Electromagnetic decay heat following thermal fission burst of 239Pu

Decay studies of neutron-rich nuclei at

Range outexperiment

LeRIBSSexperiment

+/-40 keV+/-160 keV

Isobar separator M/DM ~ 10000

Mass separatorM/ΔM ~ 1000

54 MeV protons~ 10 mA

2-3 MeV/u

200 keV

charge exchange cell

(removes Zn, Cd)~ 5% efficiency

Positiveions

Positive or negative ions

Tandem accelerator

(negative ions only)

~ 10% efficiency

IRIS-1

ORIC :~6 g 238U

fission fragments

~1011/s

b

b

g

gg

g

eg~20% eb ~60%

gas cell

Ener

gy lo

ssTotal ion energy

76Cu

76Ga

76Ge

no 76Zn !!!

Range out expgas cell spectra

C.J.Gross et al., EPJ A25,115,2005

C70-like cyclotron~100-200 mA,

70 MeV

~1013/s

50-100 g238U

MCP

HRIBF HDU Experiments

R. Page

V. Werner

J.C. Batchelder

C. Mazzocchi

A. Korgul

Decay studies : HRIBF as a world-unique ISOL facilityvery high rates + isobaric separation + ion “ranging-out” and tagging

+ powerful detectors and digital data acquisition

and the collaborations of contributing users !

photo-peakefficiency

total g-efficiency

MTASM. Karny

b DetectorE. Zganjar

3HenLSU/MS State/

UTK/ORNL

ORISS (DM/M 1:400,000)A. Piechaczek ekta-BESCA

E. Zganjar

VANDLEM. Madurga

CERDAS.N. Liddick

Summary• There are important issues in nuclear structure, nuclear astrophysics,

nuclear reactors and safety, and national security which require information from b decay.

• The HRIBF has a unique ability to provide highly purified radioactive beams with event-by-event measured intensity.

• The HRIBF currently has a powerful array of detector systems in place for this research

• A number of new detector systems are being built which will further enhance the HRIBF research

• ORISS will add to the ability to provide pure beams• The HRIBF Hadron Driver Upgrade will provide a significant increase in the

range and number of key decay experiments which can be performed.• The HRIBF HUD will bridge the gap in high-power ISOL research in the US

until CD4 FRIB.• The results from the upgraded HRIBF will create a database for the

discussion of ISOL vs. second fragmentation target options at FRIB.