Strong enhancement of two-neutron transfer in the system $^{206}$Pb+$^{118}$Sn

I. Peter; W. von Oertzen; H.G. Bohlen; A. Gadea; B. Gebauer; J. Gerl; M. Kaspar; I. Kozhoukharov; T. Kröll; M. Rejmund; C. Schlegel; S. Thummerer; H.J. Wollersheim

doi:doi:10.1007/s100500050236

2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A 4, 313-317

Short Note

Strong enhancement of two-neutron transfer in the system ²⁰⁶Pb+¹¹⁸Sn

I. Peter^1,3 - W. von Oertzen^1,2 - H.G. Bohlen² - A. Gadea³ - B. Gebauer² - J. Gerl³ - M. Kaspar³ - I. Kozhoukharov^3 a - T. Kröll³ - M. Rejmund³ - C. Schlegel³ - S. Thummerer² - H.J. Wollersheim³

¹ Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, D-14195 Berlin, Germany
² Hahn-Meitner-Institut Berlin, Glienicker Strasse 100, D-14109 Berlin, Germany
³ Gesellschaft für Schwerionenforschung Darmstadt, Planckstrasse 1, D-64291 Darmstadt, Germany

Received: 18 December 1998 / Revised version: 23 February 1999 Communicated by D. Schwalm

Abstract
One and two neutron transfer has been measured in the heaviest asymmetric nuclear system with semi magic nuclei showing superfluid properties, in ²⁰⁶Pb+¹¹⁸Sn collisions at an energy well below the Coulomb barrier with scattering orbits covering the largest angles. Particle- $\gamma$ coincidence techniques using 5 Euroball-Cluster detectors (EB) combined in a set-up with the Heidelberg-Darmstadt NaI-Crystal Ball (CB) have been used. Transfer channels are identified with EB via their known $\gamma$ -decays of the lowest excited states. Using the unique feature of the set-up with the CB, transfer to well defined final states with known quantum numbers (without feeding) are selected using the high efficiency multiplicity filter of the CB (no second $\gamma$ -ray). The data are analysed using the semiclassical approach and transfer probabilities are obtained. The enhancement for the two-neutron transfer populating the low lying superfluid 2⁺ state in ¹²⁰Sn (and ¹¹⁶Sn), while the Pb-branch is in the groundstate is deduced by comparison with the strongest single neutron transfer transition. Large enhancements (EF $\simeq$ 10³) are observed. This is the first direct measurement of enhancement for a heavy nuclear binary system with experimentally separated levels suggesting a strong contribution from superfluid pair transfer.