25MeV/u^6He在~9Be靶上引起的双中子转移

Two-Neutron Transfer Induced by ~6He Nuclear Beam at 25MeV/u on a ~9Be Target

报道了经仔细设计的 15 0MeV6He +9Be实验 ,并在质心系大角度处测量 10 Be和 11Be同位素产物的实验数据 .鉴别得到相应于单中子转移的 371个 10 Be事件 ,同时观测到了相应于双中子转移的 5个 11Be事件 .由此得到相应微分截面分别为 (0 .11± 0 .0 2 )mb sr(θcm≈ 137.4°)和 (1.0± 0 .7)μb sr(θcm≈ 133.4°) ,结果表明在所研究的反应体系中 ,单中子转移截面要比双中子转移截面约大10 0倍 .在 6He由 5He n和α 2n组成的集团模型下 ,利用零力程扭曲波玻恩近似 (DWBA)的计算程序 ,在数量级上重现了单。

n-and 2n-transfer reaction products 10Be and 11Be at large c.m. angles were measued in a specially designed set-up for the bombardment of 9Be by 6He at 150MeV. In total 371 10Be and 5 11Be events, corresponding to 1n-and 2n-transfer respectively were identified. The experimental differential cross-sections obtained are 0.11±0.02mb/sr(θ cm≈137.4°) and 1.0±0.7μb/sr(θ cm≈133.4°) for 1n- and 2n-transfer, respectively. Such results indicate that the differential cross-section of 1n-transfer is about 100 times higher than that of 2n-transfer at large c.m. angle in the reaction studied. Calculation using zero range Distorted Wave Born Approximation(DWBA) for 6He under 5He-n and α-2n two-cluster models are performed and discussed.