Study of the Near-barrier Scattering of $^8$He on $^{208}$Pb

Abstract

The structure and dynamics of 8 He have been studied through the collision process with a 208 Pb target at energies of 22 and 16 MeV, above and below the Coulomb barrier, respectively. The energy and angular distributions of the elastically scattered 8 He and the 6,4 He fragments were measured. In this paper, we discuss the method used to determine the effective position of the beam spot on the reaction target and the scattering and solid angles of each pixel of the detector array.

An Analysis of Heavy-Ion Elastic Scattering Processes Using Numerical Model Based on the Partial Wave Parameterised S-Matrix with Regge Pole Factor

“…The observed data of angular distribution of both elastic scatterings of 8 He and 6 He exhibit a similar trend up to the grazing angle. A larger reduction in cross section for the angular distribution of elastic scattering of 8 He at larger angles is also noticed [35]. Regarding the reduction in cross section, the information that really matters is as follows: (1) 8 He and 6 He have 1n and 2n systems with similar binding energies, (2) the skin nucleus 8 He has a tighter neutron layer than the α + 2n system (or 6 He) and (3) the break-up of α + 2n system (in case of 6 He) is energetically favourable.…”

“…Scattering of 4,6,8 He by Target Nucleus 208 Pb Figure 2 shows the experimental data of angular distribution of elastic scattering for 4,6,8 He + 208 Pb elastic scattering at laboratory energy of 22 MeV [35][36][37] together with the calculated results of angular distribution using FVM and the combined model. The theoretical results of our adopted models are consistent with experimental data for 4 He [36,37].…”

“…Then, it becomes distorted such that the positively charged core moves in the direction of the field while the halo neutrons move in the opposite direction (in the centre of mass frame). In an earlier study, the molecular two-state approximation was performed to analyse the angular distributions of the systems 19 F + 16 In the present study, the available experimental angular distributions in the elastic scattering of 9,10,11 Be from 64 Zn at a laboratory energy of 27.95 MeV [34], and 4, 6, 8 He + 208 Pb at a laboratory energy of 22 MeV [35][36][37] will be analysed, using the strong absorption model of Frahn and Venter (SAM) [1,18,19]. The analysis of SAM will explain the diffractive features that occur at forward angles when the projectile has a nuclear halo structure.…”

“…Moreover, both OM and/or coupled reaction channel (CRC) models were employed to analyse elastic scattering and the effect of the stripping of 1n in the 4,6,8 He + 208 Pb collision, at a laboratory energy of 22 MeV [35][36][37]. Some of these collisions involve a halo nucleus with energy around the Coulomb barrier.…”

Precise measurement of near-barrier He8+Pb208 elastic scattering: Comparison with HeMarquínez-Durán1, Martel2, Sánchez-Benítez3 et al. 2016Phys. Rev. CSelf Cite18090View full textAdd to dashboardCite

“…These assignments are the result of a determination of the effective relative position of the beam spot on target with respect to the detector array (further explained in Ref. [11]). The main tool used in the search for this position was the NPTOOL package [12] for the simulation of the experimental setup, with the aim of reproducing its performance during the experiment.…”