THE STUDIES OF NON-RUTHERFORD BACKSCATTERING CROSS SECTIONS OF 4He FROM 16O

In this article, we report the 170° backscattering cross sections of ⁴He from ¹⁶O in the energy range of 2.0-9.0 MeV. Our measurements show that the alpha-oxygen scattering remains Rutherford scattering up to E_α=2.35 MeV, and there exist two energy regions, namely 5.55-5.85MeV and 8.50-8.80MeV, where the cross sections are enhanced and show a smooth variation. The measured laboratory cross sections are 9.50-9.97 and 35.0-33.0 times greater than the Rutherford values, respectively. In the 8.50-8.80MeV region, the cross sections at scattering angles of 160°, 165°, 170° and 175° were measured and found to be strongly angle-dependent. A most strong resonance occurred at 7.60 MeV, where the cross section is 200 times of its Rutherford value. This resonance has been used to measure the ¹⁶O concentration on a Cu surface, with a sensitivity of 1×10¹⁵ oxygen atoms/cm², Besides, we have studied the backscattering angle dependence of the threshold energy, i.e., the energy at which the elastic cross section begins to deviate from its Rutherford value. The experimental result seems not in agreement with the prediction made from the analytical formula developed by Bozoian et al.     

用卢瑟福背散射和核反应技术测定Y-Ba-Cu-O超导体的元素配比

本文报道了用卢瑟福背散射和核反应~(16)O(d,P_1)~(17)O测定超导Y-Ba-Cu-O体系元素配比的实验结果。发现在煅烧后成为超导体的样品,其实际组分中Y和O的含量均低于煅烧后为非超导体的样品,且在煅烧时与氧气充分接触的部分,其实际组分中氧含量反而较小。本工作还提示了要得到性能良好的薄膜或提高电流负载,必须对各种工艺条件下生成的超导体中所有元素的实际配比进行测定而不能依赖于名义值。     

清凉寺窑与张公巷窑青瓷釉料的主量化学组成

用质子激发X射线荧光分析(Proton induced X-ray emission为PIXE)测定宝丰清凉寺窑汝官瓷、汝民瓷和汝州张公巷窑青瓷釉的7种主量元素的化学组 分, 将这些测量数据进行散布分析和模糊聚类分析, 以确定它们的分类和起源关系. 结果表明, 清凉寺窑汝官瓷与汝民瓷的釉料配方明显不同, 汝官瓷釉料配方稳定, 而且釉料来源集中; 清凉寺窑汝官瓷釉与汝州张公巷窑青瓷釉的原料来源和配方不完全相同, 汝州张公巷窑青瓷釉的原料来源比较分散.     

低能沟道效应及其应用

带电粒子在晶体中的运动会受到沟道效应和阻塞效应的强烈影响。本文评述了能量为Mev的质子和氦离子在晶体中的沟道效应及其在固体物理、半导体物理、表面物理和原子物理中的应用,同时也叙述了我们实验室在近几年来得到的各种实验结果。     

真,假钞的X荧光鉴别法

首次报道了用质子激发Ｘ荧光法鉴别假钞的实验结果。实验采用ＰＩＸＥ能谱法测定纸币印刷油墨的化学元素成分和相对含量,依此来判定人民币的真,假,实验结果表明,该方法不仅可以识别人民币的真与假,而且也可双判定假钞种类的异同,这对于追踪假钞的来源或制造地是有用的。