Silze A, Zschornack G, Ovsyannikov V P, Ullmann F
Institut fur Angewandte Physik, Technische Universitat Dresden, Helmholtzstrasse 10, D-01062 Dresden, Germany.
Rev Sci Instrum. 2008 Aug;79(8):083302. doi: 10.1063/1.2960568.
The evolution of the charge state distribution inside an electron beam ion source or trap (EBIS/T) is determined by interactions of the electron beam with the ions in the trap region. Hence, detailed information about the electron beam is required for evaluations of spectroscopic and ion extraction measurements performed at EBIS/T facilities. This article presents the results of investigations on the electron beam properties of an ion source of the Dresden EBIS type. For the first time theoretical predictions of the shape of the beam were tested for a noncryogenic EBIS working with low magnetic flux densities provided by permanent magnets. Position and width of the electron beam were measured at different electron energies showing an oscillation in the beam structure. At an energy of E(e)=16 keV and an emission current of I(e)=30 mA the beam is compressed to a radius of r(e)=57 mum (80% current). This refers to an average current density of j(e)=232 A/cm(2).
电子束离子源或阱（EBIS/T）内部电荷态分布的演变取决于电子束与阱区离子之间的相互作用。因此，在评估EBIS/T设施进行的光谱测量和离子提取测量时，需要有关电子束的详细信息。本文介绍了对德累斯顿EBIS型离子源电子束特性的研究结果。首次对由永久磁铁提供低磁通密度的非低温EBIS的束流形状进行了理论预测测试。在不同电子能量下测量了电子束的位置和宽度，结果显示束流结构存在振荡。在电子能量E(e)=16 keV和发射电流I(e)=30 mA时，束流被压缩到半径r(e)=57μm（80%电流）。这对应于平均电流密度j(e)=232 A/cm²。
