1. New Transuranium Isotopes in Multinucleon Transfer Reactions
Observation of
New Transuranium Isotopes in
Multinucleon Transfer Reactions
Sophie Heinz
GSI Helmholtzzentrum and Justus-Liebig-Universität Gießen
NRNN2017, October 25 – 26, 2017, Messina, Italy

2. Physics at the boarders of the Nuclear Chart
New decay modes
Proton emission
Exotic nuclear structure
Halo nuclei
Astrophysical
nucleosynthesis
Superheavy nuclei
118 known elements
~ 3000 known isotopes
~ 4000 still unknown isotopes

3. Production of Exotic Nuclei
1) Fragmentation reactions (100 – 1000 MeV/u)
target
projectile
2) Fission reactions (100 – 1000 MeV/u)
3) Fusion reactions (~ 5 MeV/u)

4. ? How to Reach the Boarders of the Chart of Nuclides?
Multinucleon Transfer ?
Figure: courtesy R. Knöbel

5. The small cross-sections require separation + single event detection
Multinucleon Transfer Reactions
FUSION
Compound
Nucleus (CN)
MULTINUCLEON
TRANSFER
Fission
Fragments
Evaporation
Residue
σ << 1 μb
for new exotic nuclei
The small cross-sections require separation + single event detection

6. Isotope identification via radioactive decays
Separation with a Velocity Filter
Separation and identification of heavy reaction products at SHIP
Nbeam ≈ 5·1012 / s
Ndetector ≈ 100 / s
v ~ E/B 1 2 sf 3
E, T1/2
Isotope identification
via radioactive decays
5 ms
15 ms
ΔΘ = (0 ± 2)°; ΔΩ = 10 msr
pulsed beam structure

7. Isotope identification via radioactive decays
The Velocity Filter SHIP at GSI
Separation and identification of heavy reaction products at SHIP
Very sensitive method
Nbeam ≈ 5·1012 / s
Ndetector ≈ 100 / s
v ~ E/B 1 2 sf 3
E, T1/2
Isotope identification
via radioactive decays
5 ms
15 ms
ΔΘ = (0 ± 2)°; ΔΩ = 10 msr
pulsed beam structure
σ1 event ≈ 10 pb/sr
low limit cross-sections:
T1/2 ≥ 20 μs
access to short-living nuclei:

8. New Transuranium Isotopes Observed in MNT
Experiment at SHIP: 48Ca + 248Cm, Ecm = 212 MeV
H.M. Devaraja et al., Phys. Lett. B 748, 199 (2015).
Alpha spectrum
Isotope identification via α decays

9. Some of the New Decay Chains
U-216
U-216

10. Isotopic Distributions
▪ 1-event cross-section limit: 10 pb / sr → σtot ~ 1.9 nb with εSHIP = 0.5 %
▪ Isotopes far from the target were populated with large yields
▪ Distributions reveal long tails towards the n-deficient side (not yet understod)

11. Energy Dissipation
● Total Kinetic Energy (TKE) was deduced from the velocity spectra
● TKE < EViola for increasing distance from the target nucleus → indicates
strong deformation of the MNT products at scission point
● Excitation energy of primary target-like MNT products:
E* = Ecm − TKE = 30 – 50 MeV

12. Comparison of MNT and Fusion Reactions
Cross-sections of uranium isotopes from transfer and fusion reactions
εFusion >> εTransfer
ε: angular efficiency is small for transfer products due to wide angular spread

13. Summary and Outlook
► DIT reactions are intensively discussed as a means to produce new
isotopes in the region of superheavy nuclei and N ≈ 126 nuclei
► In DIT reactions at SHIP we observed new transuranium nuclei
→ σ1 event ~10 pb / sr
► In DIT reactions a vast region of nuclei can be populated in the same
experiment
► Are DIT reactions suitable / favourable for the production of heavy nuclei?
● Z > 92, N ≈ 126 → DIT appears favourable for n-deficient transuraniums
● Z < 82, N ≈ 126 → Fragmentation appears favourable
(O. Beliuskina et al., Eur. Phys. J. A 50, 161 (2014))
● n-rich SHN → DIT very difficult: tiny σ and missing ID techniques

14. MNT for the N ≈ 126, Z < 82 Region?
MNT in 64Ni + 207Pb
Transfer and fragmentation cross-sections
for neutron-rich nuclei: σTransfer ≥ σFragmentation
− O. Beliuskina et al., Eur. Phys. J. A 50, 161 (2014).
− [1] W. Krolas et al., Nucl. Phys. A 724 (2003) 289.

15. MNT for the N ≈ 126, Z < 82 Region?
Transfer and fragmentation yields (at the target)
Nbeam
dTarget
efficiency
Transfer
Fragmentation
5 · 1012 / s
5 · 109 / s
500 μg / cm2
5 g / cm2
~ 1% (SHIP)
~ 50% (FRS)
yield (Fragmentation) >> yield (Transfer)

16. Transfer Products from 48Ca + 248Cm
Theoretical model calculations for 48Ca + 248Cm
→ V. Zagrebaev and W. Greiner
Ecm = 210 MeV (= 1.05 VCoulomb)
cross-section (mb)
primary TP
excitation energy (MeV)