Ba同位素的截面测量

Measurement of the Cross Sections for Ba Isotopes

用 60MeV/u18O离子轰击天然铀靶 ,通过2 38U( 18O ,X)反应产生钡的放射性同位素 .使用放射化学分离方法从被照射过的铀靶中分离出Ba ,用HPGeγ射线探测器测量Ba样品的γ射线谱 ,经对所得时间累计谱的处理和分析得到了Ba同位素的产生截面 ,并观察到Ba同位素分布中的双峰分布现象 .

Present experiment was performed in order to get more information about intermediate energy heavy ion collisions for the further understanding of that how nuclear reaction mechanisms change between the two extreme types of nuclear behaviors, the nuclear collisions at low and high energy. Ba isotopes were produced by 60 MeV/u 18 O bombardment of nature uranium via 238 U( 18 O,X) reaction, and then separated from the irradiated U targets by using radiochemical procedure. The accumulative sections of Ba isotopes are obtained through the processing and analyzing of time sequence γ ray spectra. As a result, the two peak phenomenon in the distribution of the Ba isotopes is observed. It can be presumed that the occurrence of the double Gaussian distribution is weakly related to the projectile energy, but closely related to the projectile target combination. Present experiment also implied however, that fragmentation reaction induced by intermediate energy heavy ions followed by radiochemical separation is an efficacious method to produce nuclei far from stability, thereby to study their decay properties.