^(27)Al+^(27)Al耗散反应截面涨落的角度关联测量

Measurement of Angular Cross Correlation of the Cross Section Fluctuation in Dissipative Collision ^(27)Al+^(27)Al

在2 7Al+ 2 7Al(Elab≈ 1 2 0MeV)耗散反应激发函数涨落的实验研究中 ,首次在较大的角度范围内获得截面涨落的角度关联系数和角度关联函数 .实验结果表明 ,角度关联函数的形状呈现明显的非对称性 ,角度相干宽度至少为 4 0°;截面涨落在前后角区表现出明显不同的角度相关性 .

The excitation function was measured from θ lab =10.4° to 57.4° in dissipative collision 27 Al+ 27 Al with incident energy ranging from 114 to 123 MeV in step of 200 keV. The Angular cross Correlation Functions (ACFs) of cross section fluctuation within large angle region were obtained through experiment for the first time. It is found that the angular coherent width is at least 40°. It is interesting that the ACFs is not simple bell shape but shows strong asymmetry. The over all behavior is that ACF varies more quickly for the backward angles. Itis also noticed that the cross section fluctuation in the forward angle region ( θ cm <70°) shows much stronger angular coherence than in the backward angle region ( θ cm >70°). This angular dependence may be attributed to the coherent rotation effect of intermediate dinuclear system.