Multinucleon transfer in the interaction of 977 MeV and 1143 MeV Hg 204 with Pb 208

A previous study of symmetric collisions of massive nuclei has shown that current models of multinucleon transfer (MNT) reactions do not adequately describe the transfer product yields. To gain further insight into this problem, we have measured the yields of MNT products in the interaction of 977 (E/A=4.79 MeV) and 1143 MeV (E/A=5.60 MeV) Hg204 with Pb208. We find that the yield of multinucleon transfer products are similar in these two reactions and are substantially lower than those observed in the reaction of 1257 MeV (E/A=6.16 MeV) Hg204+Pt198. We compare our measurements with the predictions of the GRAZING-F, dinuclear systems (DNS), and improved quantum molecular dynamics (ImQMD) models. For the observed isotopes of the elements Au, Hg, Tl, Pb, and Bi, the measured values of the MNT cross sections are orders of magnitude larger than the predicted values. Furthermore, the various models predict the formation of nuclides near the N=126 shell, which are not observed

Modeling multi-nucleon transfer in symmetric collisions of massive nuclei

Symmetric collisions of massive nuclei, such as 238U + 248Cm, have been proposed as ways to make new n-rich heavy nuclei via multi-nucleon transfer (MNT) reactions. We have measured the yields of several projectile-like and target-like fragments from the reaction of 1360 MeV 204Hg + 198Pt. We find that current models for this symmetric collision (GRAZING, DNS, ImQMD) significantly underestimate the yields of these transfer products, even for small transfers

γ -ray spectroscopy of Tl 209

States in Tl209 were populated using a multinucleon transfer reaction with a Xe136 beam impinging on a thick Pb208 target at E=785 MeV. The beam was pulsed at 825-ns intervals in order to perform isomer decay spectroscopy. The known Jπ=17/2+ isomer in Tl209 was located at 1228(4) keV and measured to have a half-life of T1/2=146(10) ns. A second isomer with Jπ=13/2+ was found to have T1/2=14(5) ns. The previously suggested low-energy X and Y transitions were found to have energies 57(2) and 47(2) keV respectively, while the measurement of conversion coefficients and a new decay path make the spin assignments below the isomers experimentally firm. Correlating the delayed γ transitions with the prompt beam flash allowed the decay of states above the isomer to be found. The longer-lived isomer represents full alignment of the simplest two-particle, one-hole configuration and illuminates the remarkably weak coupling of the proton hole to the Pb210 core

Modeling multi-nucleon transfer in symmetric collisions of massive nuclei

Symmetric collisions of massive nuclei, such as 238U + 248Cm, have been proposed as ways to make new n-rich heavy nuclei via multi-nucleon transfer (MNT) reactions. We have measured the yields of several projectile-like and target-like fragments from the reaction of 1360 MeV 204Hg + 198Pt. We find that current models for this symmetric collision (GRAZING, DNS, ImQMD) significantly underestimate the yields of these transfer products, even for small transfers. Keywords: Multi-nucleon transfer, GRAZING predictions, DNS model, Improved Quantum Molecular Dynamics model, 204Hg + 198P