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基于多组态Dirac-Fock理论方法和冲量近似, 对Xe54+与Xe在197 MeV/u碰撞能量下, 炮弹离子的俘获及退激发过程进行了理论研究. 计算了炮弹离子从中性靶原子俘获一个电子到nl (n=1, 2, 3, 4, 5; l=s, p, d) 轨道上的辐射电子俘获截面和相应的辐射光子能量, 以及俘获末态退激发辐射跃迁的能量和概率. 结合这些计算结果, 进一步模拟了碰撞产生的炮弹离子的退激发X射线谱的结构, 并与兰州重离子加速器装置上的最新实验观测结果进行了比较, 符合得很好. 相似文献
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无论对深入理解电子-原子的作用机制,还是在材料等领域的实际应用,电子轰击原子的内壳电离截面都具有重要意义。当前电子碰撞引起原子内壳电离的实验数据多集中在几十ke V入射能量和中小Z靶原子,其它数据相对比较缺乏。本工作以能量为1.0 Me V电子轰击Ta和Au靶,通过测量靶原子特征X射线的产额,获得其K壳电离截面分别为13.3和10.1 b,L壳电离截面分别为554和338 b。并将实验结果和相应的理论进行了对比,结果显示,本实验测得的K壳电离截面与Casnati、Hombourger理论值、L壳电离截面与Scofield和Born-Bethe的理论值相符。 相似文献
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采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 pA/mm2 ~14.3 nA/mm2范围内改变入射流强,利用1 500 eV电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。Adopting several grooved parallel plates made by different insulators, such as high-purity fused quartz, Teflon, Bakelite and POM (Polyformaldehyde), and further adjusting the electron beam current in a wide range (tens of pA~tens of nA), the discharging mechanism in the self-organizing charge and discharge processes of electron guiding was investigated and discussed by using 1 500 eV incident electron beam. The present results show that, the electron guiding behaviors are obviously existing when such electron beam is transmitted through the above grooved insulating parallel plates, which are independent on beam current and insulators. Our results suggest that, the possibilities of the accumulated charges on inner-surface of grooved parallel plates linearly discharging through surface and bulk resistances of plates into the ground should be excluded. 相似文献
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宏观尺寸弯曲石英管对中低能电子束的导向作用 总被引:1,自引:0,他引:1
研究了宏观尺寸的弯曲圆柱形石英管对 1 100, 1 300和1 500 eV 3种能量电子束的导向作用, 并对实验结果与相同材质和尺寸的直管的情形进行了分析对比。 实验中利用一个位置灵敏法拉第筒对从石英管出射的电子束进行探测, 获得从管道中出射的电子束流强度在位置灵敏法拉第筒各道上的分布, 其结果显示宏观尺寸石英管对电子束存在导向作用。 与慢速高电荷态离子和绝缘毛细管相互作用的物理过程类似, 这种导向效应是由电荷在管壁内表面自组织充电引起的。 实验还发现, 入射电子束流的强度越强, 其导向作用越明显, 这与微观尺寸毛细管对慢速高电荷态离子的导向作用不同。 石英管导向能力与管的尺寸、 形状及材料之间的关系还有待进一步的系统研究。 It was inevstigated in the experiment that the guiding effect of electron beam with energy of 1 100, 1 300 and 1 500 eV through a bended cylindrical quartz tube with macro sized. A position sensitive Faraday cup was developed and used to detect the electron beam transmitted through the quartz tube, and the distribution of transmitted beam current on each channel of the Faraday cup was acquired. Results indicate the existence of guiding effect which is due to the self organized charge up in the inner wall of the quartz tube similar to that of the highly charged ions. We also found that the guiding ability of the tube is related to the incident beam intensity. The relationship between the guiding ability and the material as well as the size of the tube is to be studied in the near future. 相似文献
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X-Ray Emission from Zr, Mo, In and Pb Targets Bombarded by Slow Highly Charged Ar^q+(q = 13, 14, 15, 16) Ions 总被引:1,自引:0,他引:1 下载免费PDF全文
We study the L x-ray emission from Zr, Mo and In targets and M x-ray emission from Pb target under bombardment of low energy Ar^q (q = 13, 14, 15, 16) ions. The relative x-ray yields were measured in the projectile kinetic energy range 210-360 keV. It is found that the relative x-ray yields from Zr, Mo and Pb targets increase with the increasing projectile kinetic energy for Ar^14 and Ar^16 projectiles and depend on the potential energy of the projectile remarkably. 相似文献
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用345 keV的Kr15+和340 keV的Kr17+离子以45fi角入射n型GaAs单晶(100)面,测量了表面形貌的变化和发射的375—500 nm Ga I和Kr II的特征光谱线.Krq+(q=15,17)离子轰击后表面形貌的变化主要取决于入射离子的电荷态q.离子沉积到靶表面的能量引起Ga原子激发,其辐射光谱为Ga I 403.2 nm和Ga I 417.0 nm.入射离子中性化过程中俘获GaAs导带电子形成高激发态原子,通过级联退激填充3p,4d等空穴,P壳层电子跃迁发射谱线为Kr II 410.0 nm,Kr II 430.4 nm,Kr II 434.0 nm和Kr II 486.0 nm,Kr II486.0 nm为较强谱线.实验结果表明,入射离子与GaAs单晶相互作用发射的可见光产额与入射离子的电荷态密切相关,较高电荷态Kr17+离子入射产生的光辐射产额大约为Kr15+离子的两倍. 相似文献
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