The total reaction cross section (1724±93 mb) of 17B at the energy of 43.7 A MeV on C target has been measured by using the transmission method at the Radioactive Ion Beam Line in Lanzhou (RIBLL). Assuming 17B consists of a core 15B plus two halo neutrons,the total cross section of 17B on C target was calculated with the zero-range Glauber model,where double Gaussian density distributions and Gaussian plus HO density distributions were used. It can fit the experimental data very well. The characteristic of halo structure for 17B was found with a large diffusion of the neutrons density distribution.
HU ZhengGuo1, WANG Meng1, XU HuShan1, SUN ZhiYu1, WANG JianSong1, XIAO GuoQing1, ZHAN WenLong1, XIAO ZhiGang1, MAO RuiShi1,2, LI Chen1, ZHANG XueYing1,2, ZHANG HongBin1, ZHAO TieCheng1, XU ZhiGuo1, WANG Yue1,2, CHEN RuoFu1,2, HUANG TianHeng1,2, FU Fen1,2, GAO Qi1,2, HAN JianLong1,2, ZHANG XueHeng1,2, ZHENG Chuan1,2, YU YuHong1,2 & GUO ZhongYan1 1 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
The reaction cross section of 17B on 12C target at （43.7±2.4） MeV/u has been measured at the Radioactive Ion Beam Line in Lanzhou （RIBLL）. The root-mean-square matter radius （Rrms） was deduced to be （2.92±0.10） fro, while the Rrras of the core and the valence neutron distribution are 2.28 fm and 5.98 fm respectively. Assuming a ＂core plus 2n11 structure in 17B, the mixed configuration of （2s1/2） and （1d5/2） of the valence neutrons is studied and the s-wave spectroscopic factor is found to be （80±21）%.
A microscopic cluster model with a fully correlated Gaussian basis is developed. In the model, the stochastic variational method is used in order to calculate the ground-energy and the mean-square radius conveniently. Based on this model, the ground-energy level and radius of the neutron halo nucleus, ^6He, are calculated as a α＋n＋n three-cluster model. The results are in good agreement with the experimental data.
