On the origin of the 2485 keV?-ray observed in near-barrier collisions of various heavy ions with208Pb

Abstract

In collisions of 64Ni and 82Se projectiles with a thick 208Pb target at energies around 10% above the static Coulomb barrier a 2485 keV y-ray is observed, which is in conspicuous agreement with the recently reported y-ray deexeiting the two-phonon octupole state in 208Pb [1]. The y-ray observed in the present toDo experiments is not in coincidence with any known 208Pb y-rays, but belongs likely to207Pb.

Structure of $^{207}$Pb Populated in $^{208}$Pb + $^{208}$Pb Deep-inelastic Collisions

“…The level scheme of 207 Pb up to ∼ 6 MeV is presented, and is in agreement with the previous work by Schramm et al [2]. An additional excited state and three γ rays were identified.…”

“…The deduced level scheme up to ∼ 6 MeV, shown in Fig. 3, is in agreement with the previous work of Schramm et al [2]. A 57 keV γ ray is inferred from coincidence relationships.…”

“…Schramm et al were the first to suggest that a 2485 keV transition lies above the 13/2 + state in 207 Pb [2]. The 2485 keV transition was placed connecting a (19/2 − ) state to the 13/2 + isomer, with the expectation that it is a collective E3 transition.…”

High-spin states and isomers in the one-proton-hole and three-neutron-hole204Tl isotope

“…Although the corresponding E3 transition above the 33/2 + 205 Pb isomer has not yet been identified experimentally, the expected energy shift can be estimated. The ∆E = −129 keV shift known for the E3 excitation above the i 13/2 hole state in 207 Pb [29] and the ∆E = −212 keV shift observed for the E3 excitation above the 12…”

High-spin states in neutron-rich nuclei explored with deep-inelastic HI reactions

“…Since nearly a decade we are successfully using the deep-inelastic heavy-ion reactions for spectroscopic studies of nuclei located at the neutron-rich edge of the beta stability valley and beyond (e.g., [1][2][3][4][5][6]). The high-quality gamma coincidence data obtained in thick-target experiments performed with available large arrays of germanium detectors allow to achieve selectivity which is satisfactory to identify structures of many previously unknown nuclei.…”