Burrows M D, Ryan S R, Lamb W E, McIntyre L C
Department of Physics, University of Arizona, Tucson, Arizona 85721.
Rev Sci Instrum. 1979 Oct;50(10):1278. doi: 10.1063/1.1135696.
A novel mass filter and focusing ion detector for time-of-flight studies of dissociative ionization fragments is described. The filter-dector combination is particularly suited for measuring the kinetic energy released in the molecular dissociation process. The mass filter utilizes a computer-controlled, time-dependent retarding potential synchronized with, and located a distance L from, a pulsed electron-bombardment ion source. Ions arriving at the filter at time t have a kinetic energy of mL(2)/2t(2). The retarding potential varies with time as mL(2)/2et(2), thus deflecting ions with masses less than m. Operation of the filter in a mode which provides unity mass resolution at 16 amu has been demonstrated. The detector consists of a channel electron multiplier and a focusing electrode configuration approximating that of a charged sphere above a grounded conducting plane. The planar input aperture of the detector is located just behind the mass filter along the ion flight path. The detector features high efficiency, large input aperture, low background, and simple operation. Ion transit times through the detector are small and essentially independent of the initial ion kinetic energy.
本文描述了一种用于离解电离碎片飞行时间研究的新型质量过滤器和聚焦离子探测器。该过滤器 - 探测器组合特别适用于测量分子解离过程中释放的动能。质量过滤器利用计算机控制的、与脉冲电子轰击离子源同步且相距距离L的随时间变化的减速电位。在时间t到达过滤器的离子具有动能mL²/2t²。减速电位随时间变化为mL²/2et²，从而使质量小于m的离子发生偏转。已经证明该过滤器在16原子质量单位下以提供单位质量分辨率的模式运行。探测器由一个通道电子倍增器和一个聚焦电极配置组成，该配置近似于接地导电平面上方带电球体的配置。探测器的平面输入孔径沿离子飞行路径位于质量过滤器的正后方。该探测器具有高效率、大输入孔径、低背景和操作简单的特点。离子通过探测器的传输时间很短，并且基本上与初始离子动能无关。
