1. Study of SHE at the GSI – SHIP
International School of Nuclear Physics, 30th Course
Heavy-Ion Collisions from the Coulomb Barrier to
the Quark-Gluon Plasma
Study of SHE at the GSI – SHIP
Sigurd Hofmann
GSI Darmstadt and Goethe-University Frankfurt
September 16-24, 2008, Erice, Sicily

2. SHE Calculated half-lives: 108 years – 1 ns trans-actinides
spherical
nuclei
deformed
trans-actinides
actinides
proton number
stabile elements
neutron number

3. Predictions of the macroscopic-microscopic model

4. Expected half-lives of SHE and research goals
even-
even
Location of closed shells:
Proton shell:
114, 120 or 126 / 114 – 126 ?
Neutron shell:
172 or 184 ?
Reaction mechanism:
Cross-sections
Excitation functions
Cross bombardments
Mass asymmetry
Fusion and transfer
Nuclear structure:
Lifetimes
Decay modes
Isomers
even-
odd 6 3

5. The "UNIversal Linear ACcelerator" UNILAC
Rc 1505; 2f18

6. Velocity separator SHIP
Separation time: – 2 μs
Transmission: – 50 %
Background: – 50 Hz
Det. E. resolution: – 25 keV
Det. Pos. resolution: μm
Dead time: – 25 μs
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7. Detector system Time: F3 – F1 1 s Energy: Estop: Ebox: Position:
Sistop,box – F1,2, s
Sistop – Sibox s
Sistop,box – Ge1,2,3, s
Dead time: and 25 s
Energy:
Estop: Ebox:
0.2 – 16; – 16 MeV
5.0 – 320; – 160 MeV
Eveto: 0.4 – MeV
Ge: – 2000 keV
0.1 – MeV
Position:
Stop x = – 80 mm / 5 mm
ytop,bottom = 0 – 35 mm / 0.2 mm
Box: 28 Segments
Fusions-
Produkte

8. Energy versus time-of-flight plots, Δt (ER-sf) = 1000 s
252No
E / MeV
206Pb
48Ca
48Ca + 206PbS => 254No*
238U
48Ca + 238U => *
–TOF / channel

9. Longest decay chain of 277112 Known nuclei 277112 CN 273110 11.45 MeV
253Fm
8.34 MeV
15.0 s
yER = 17.9 mm
277112
y = 150 m (FWHM)
269108
11.08 MeV
110 s
y = 35 mm
257No
8.52 MeV
4.7 s
265106
9.23 MeV
19.7 s
261104
4.60 MeV (escape)
7.4 s
Known nuclei
d = 300 m

10. First decay chain of element 112
Experiment, GSI-SHIP,
9. February 1996, 22:36 h
Theory, P. Möller, 1995:
Ground-state
shell correction energy

11. Reaction mechanism Excitation functions 50Ti, 54Cr, 58Fe, 64Ni, 70Zn
+ 208Pb