investigation of short-lived nuclei using ribs reiner krücken physik department e12 technische...
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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
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