Sigurd HofmannGSI Darmstadt and Goethe-University Frankfurt

Study of SHE at the GSI – SHIP

September 16-24, 2008, Erice, Sicily

International School of Nuclear Physics, 30th Course

Heavy-Ion Collisions from the Coulomb Barrier to the Quark-Gluon Plasma

Neutron num ber

Pro

ton

nu

mb

er

100 110 120 130 140 150 160 170 180 190

120

110

100

90

80

70

actinides

stabile elements

trans-actinides

SHE

sphericalnucleideformed

nuclei

deformednuclei

sphericalnuclei

Calculated half-lives: 108 years – 1 ns

neutron number

pro

ton

nu

mb

er

Predictions of the macroscopic-microscopic model

Expected half-lives of SHE and research goals

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-even

even-odd

03

6

Rc 1505; 2f18

The "UNIversal Linear ACcelerator" UNILAC

Mastertitelformat bearbeiten

Velocity separator SHIP

SHIP: Separation time: 1 – 2 μs

Transmission: 20 – 50 %

Background: 10 – 50 Hz

Det. E. resolution: 18 – 25 keV

Det. Pos. resolution: 150 μm

Dead time: 3 – 25 μs

Detector system

Time:

F3 – F1 1 s Sistop,box – F1,2,3 4 s Sistop – Sibox 5 s Sistop,box – Ge1,2,3,4 5 s

Dead time: 3 and 25 s

Energy:

Estop: Ebox: 0.2 – 16; 0.2 – 16 MeV 5.0 – 320; 2.5 – 160 MeV

Eveto: 0.4 – 16 MeV Ge: 30 – 2000 keV 0.1 – 8.0 MeV

Position:

Stop x = 0 – 80 mm / 5 mm ytop,bottom = 0 – 35 mm / 0.2 mm

Box: 28 Segments

Fusions-Produkte

Energy versus time-of-flight plots, Δt (ER-sf) = 1000 s

–TOF / channel

48Ca + 238U => 286112*

48Ca + 206PbS => 254No*

48Ca

206Pb

252No

E /

MeV

238U

Longest decay chain of 277112

277112

273110

11.45 MeV280 s

269108

11.08 MeV110 s

265106

9.23 MeV19.7 s

257No

8.52 MeV4.7 s

261104

4.60 MeV (escape)7.4 s

CN

y =

15

0

m (

FW

HM

)

d = 300 m

y =

35

mm

253Fm

8.34 MeV15.0 s

y ER =

17

.9 m

m

277112

Known nucl

ei

First decay chain of element 112

Theory, P. Möller, 1995:

Ground-state

shell correction energy

Experiment, GSI-SHIP,

9. February 1996, 22:36 h

Reaction mechanism

Excitation functions

50Ti, 54Cr, 58Fe, 64Ni, 70Zn

+ 208Pb

1n

2n

3n