Investigation of short-lived nuclei using RIBs

Reiner Krücken

Physik Department E12Technische Universität München

Maier-Leibniz-Laboratoriumfür Kern- und Teilchenphysik

der Ludwig-Maximilians-Universität Münchenund der Technischen Universität München

Cycle of matter: Nucleosynthesis

Nuclear chart

Example: r-proce

ss

r-Process abundance for metal poor stars

40 50 60 70 80 90-2

-1

0

1

element number

abun

danc

e lo

g(X

/H)-

12CS22892-052 (Sneden et al. 2003)

solar r

Nuclei along the r-process

K.L. KratzRussbach 2006

r-process abundances not well described by current models

G. Martinez Pinedo et al.

Pfeiffer et al.

Shell quenching or fission or …?

Modifications of shell structure in neutron-rich nuclei

rV

Valley of stabilityValley of stability

rV

Neutron-rich nuclei

Neutron-rich nuclei

centralLS Vdr

dV Spin-orbit coupling

•How does the central potential change with neutron excess?

•What is the isospin dependence of the spin-orbit interaction?

Lack of predictive power of mean-field models

from RIA Whitepaper

M. Bender, P.H. Heenen, P.G. ReinhardRev. Mod. Phys. 75 (2003) 122

What we can measure in the laboratory?

• Masses, Q-values

• Half-lives T1/2

• Beta-delayed neutron emission probabilities Pn

• Evolution of single-particle structure and collectivity probing of shell structure working towards reliable theoretical models

• low-lying dipole strength important for e.g. (,n)

Production of short-lived radioactive beams

Isotope Separation On-Line

Diffusion out of thick target:- depends on chemistry-Slow process

Fragments fly forward with beam velocity (30-90% c)-Physical separation only- Fast separation

Reaction of light projectile (p, d, n) on a heavy target- Spallation- Fission- Fragmentation

Exotic nucleus produced in-flight as fragment of heavy beam-Fragmentation-Fission

1.4 GeV

REX-ISOLDE

MINIBALL

From PS Booster

UNILAC

SIS

FRS

ESR

Target Area

Therapy

Ion source

Max. 90% c(2 GeV/nucleon)

Experimental hall8-20% c

(3-20 MeV/nucleon)

Ion source(high Q)

N

Gesellschaft für Schwerionenforschung (GSI)in Darmstadt

Production of 100Sn and T1/2 of rp-process nuclei

E

E

TOF

First production of 100Sn

124Xe beamE= 1 A.GeV

TUM

T. Faestermann et al., EPJA 15 (2002) 185A. Stolz et al.

FAIR: Facility for Antiproton and Ion ResearchPrimary Beams

• 1012/s; 1.5-2 GeV/u; 238U28+

• Factor 100-1000 over present in intensity

Secondary Beams

• Broad range of radioactive beams

up to 1.5 - 2 GeV/u; • up to factor 10 000 in intensity over present

• Antiprotons 3 - 30 GeV

Storage and Cooler Rings

•Radioactive beams

•e- - A and Antiproton-A collider

100 m

UNILAC SIS 18

SIS 100/300

HESR SuperFRS

NESR

CRRESR

GSI todayGSI today

Future FacilityFuture Facility

ESR

Current experimental program

Coulomb excitation @ REX-ISOLDE- N=40-50 Ni, Cu, Zn- Cd, Xe, Ba around N=82

Decay spectroscopy and T1/2:

- 100Sn and vicinity (GSI, RIKEN)- A~90 Ge,As,Se (ILL Grenoble)- 128Pd and vicinity (GSI)- below 208Pb (GSI)

Probing evolution of shell structure- knock-out and inelastic excitation:

- 55Ti, 73Cu (GSI)- 42Si, 54Ca and vicinity (RIKEN)

- transfer reactions at REX-ISOLDE- ~ 32Mg, ~ 68Ni

Reach of mass- and T1/2 measurements at FAIR

Source:ILIMA collaboration

Other future facilities:RIBF @ RIKENHIE-ISOLDE @ CERNSPIRAL2 @ GANILISF @ MSU

Summary

• Properties of nuclei involved in nucleosynthesis are often not well known experimentally

• Theoretical models and extrapolations vary significantly lack of reliable predictions

• Current and future radioactive beam facilities allow for– Investigation of key nuclei to distinguish between

theoretical models towards a unified nuclear theory– Direct measurement of properties of relevant nuclei

• Local groups (LS Krücken, LS Habs) involved in experiments and methodical developments

• New Professorship in Nuclear Astrophysics will strengthen local effort