Time-of-flight Secondary Ion Mass Spectrometry (TOF SIMS) with MeV primary ions offers a fine balance between secondary ion yield for molecules in the mass range from 100 to 1000 Da and beam spot size, both of which are critical for imaging applications of organic samples. Using conically shaped glass capillaries with an exit diameter of a few micrometers, a high energy heavy primary beam can be collimated to less than 10 μm. In this work, imaging capabilities of such a setup are presented for some organic samples (leucine-evaporated mesh, fly wing section, ink deposited on paper). Lateral resolution measurement and molecular distributions of selected mass peaks are shown. The negative influence of the beam halo, an unavoidable characteristic of primary beam collimation with a conical capillary, is also discussed. A new start trigger for TOF measurements based on the detection of secondary electrons released by the primary ion is presented. This method is applicable for a continuous primary ion beam, and for thick targets that are not transparent to the primary ion beam. The solution preserves the good mass resolution of the thin target setup, where the detection of primary ions with a PIN diode is used for a start trigger, reduces the background, and enables a wide range of samples to be analyzed.

中文翻译：

---

使用兆电子伏特飞行时间二次离子质谱毛细管微探针对有机样品进行成像。

使用 MeV 初级离子的飞行时间次级离子质谱 (TOF SIMS) 在质量范围为 100 至 1000 Da 的分子的次级离子产率和束斑尺寸之间实现了良好的平衡，这两者对于成像应用至关重要有机样品。使用出口直径为几微米的圆锥形玻璃毛细管，可以将高能重初级光束准直至小于 10 μm。在这项工作中，针对一些有机样品（亮氨酸蒸发网、飞翼部分、沉积在纸上的墨水）展示了这种设置的成像能力。显示了选定质量峰的横向分辨率测量和分子分布。还讨论了光束晕的负面影响，这是使用锥形毛细管进行初级光束准直的不可避免的特性。提出了一种基于检测初级离子释放的次级电子的 TOF 测量的新启动触发器。这种方法适用于连续的初级离子束，以及对初级离子束不透明的厚目标。该解决方案保留了薄靶设置的良好质量分辨率，其中使用 PIN 二极管检测初级离子作为启动触发器，降低了背景，并允许分析范围广泛的样品。