Interaction of11Li with208Pb

Abstract

Background:11 Li is one of the most studied halo nuclei. The fusion of 11 Li with 208 Pb has been the subject of a number of theoretical studies with widely differing predictions, ranging over four orders of magnitude, for the fusion excitation function.Purpose: To measure the excitation function for the 11 Li + 208 Pb reaction. Methods: A stacked foil/degrader assembly of 208 Pb targets was irradiated with a 11 Li beam producing center of target beam energies from above barrier to near barrier energies ( 40 to 29 MeV). The intensity of the 11 Li beam (chopped) was 1250 p/s and the beam on-target time was 34 hours. The α-decay of the stopped EVRs was detected in an α-detector array at each beam energy in the beam-off period (the beam was on for ≤ 5 ns and then off for 170 ns).Results: The observed nuclidic yields of 212/215 At and 214 At are consistent with being produced in the complete fusion of 11 Li with 208 Pb. The observed yields of 213 At appear to be the result of the breakup of 11 Li into 9 Li + 2n, with the 9 Li fusing with 208 Pb. The magnitudes of the total fusion cross sections are substantially less than most theoretical predictions.Conclusions: It is possible to measure the evaporation residue production cross-sections resulting from the interaction of 11 Li with 208 Pb using current generation radioactive beam facilities. Both complete fusion and breakup fusion processes occur in the interaction of 11 Li with 208 Pb. An important breakup process leads to the fusion of the 9 Li fragment with 208 Pb .

Recent developments in fusion and direct reactions with weakly bound nuclei

“…So, there was no experimental fusion excitation function for this nucleus available. Very recently, the first preliminary experiment on 11 Li fusion has been reported [349]. The experiment was performed by Vinodkumar et al [349], at the ISAC2 facility at TRIUMF.…”

“…Very recently, the first preliminary experiment on 11 Li fusion has been reported [349]. The experiment was performed by Vinodkumar et al [349], at the ISAC2 facility at TRIUMF. They measured the TF cross section for the 11 Li + 208 Pb system, which has been investigated in several theoretical works (for a review see Ref.…”

Elastic scattering, fusion, and breakup of light exotic nuclei

“…Since 11 Li is a nucleus with more-diffuse density and a high probability of breakup, [100][101][102][103][104] and the symbols are the data from ref. [89]. Figure reprinted with permission from ref.…”

“…The only fusion measurement induced by a 11 Li beam was very recently performed at the ISAC2 facility at TRIUMF on a 208 Pb target [89]. In this experiment, the 40 MeV post-accelerated 11 Li beam, with an intensity of about 10 3 pps, impinged on a stack of 208 Pb targets.…”

“…Recently, a reliable beam of 11 Li became available at the post-accelerated ISAC-II line of the TRIUMF facility (Vancouver, Canada). The intensity achieved for this beam was about 5 × 10 3 particles/s, enough for elastic-scattering [81], breakup [88], and fusion [89] measurements on a 208 Pb target. These measurements are reviewed below.…”