Data for: Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector

A detection system based on a microchannel plate with a delay line readout structure has been developed to perform scanning transmission ion microscopy (STIM) in the helium ion microscope (HIM). This system is an improvement over other existing approaches since it combines the information of the scanning beam position on the sample with the position (scattering angle) and time of the transmission events. Various imaging modes such as bright and dark field or the direct image of the transmitted signal can be created by post-processing the collected STIM data. Furthermore, the detector has high spatial and time resolution, is sensitive to both ions and neutral particles over a wide energy range, and shows robustness against ion beam-induced damage. A special in-vacuum movable support gives the possibility of moving the detector vertically, placing the detector closer to the sample for the detection of high-angle scattering events, or moving it down to increase the angular resolution and distance for time-of-flight measurements. With this new system, we show composition-dependent contrast for amorphous materials and the contrast difference between small and high angle scattering signals. We also detect channeling related contrast on polycrystalline silicon, thallium chloride nanocrystals, and single crystalline silicon by comparing the signal transmitted at different directions for the same data set.

本研究开发了一种搭载延迟线读出结构的微通道板（microchannel plate）探测系统，用于氦离子显微镜（helium ion microscope, HIM）中的扫描透射离子显微术（scanning transmission ion microscopy, STIM）。相较于现有其他方案，该系统性能更优，因为它可将扫描束在样品上的位置信息，与透射事件的位置（散射角）和时间信息相结合。通过对采集到的STIM数据进行后处理，可生成多种成像模式，包括明场、暗场成像以及透射信号的直接成像。此外，该探测器具备优异的空间与时间分辨率，可在宽能区范围内对离子与中性粒子均实现灵敏探测，且对离子束诱导的损伤具有较强耐受性。特制的真空室内置可移动支架支持探测器的垂直位移：可将探测器向样品方向靠近，以探测大角度散射事件；也可将探测器下移，以提升飞行时间测量所需的角分辨率与探测间距。借助这套新型系统，本研究实现了非晶材料的成分依赖衬度成像，同时观测到小角度与大角度散射信号间的衬度差异。此外，通过对同一数据集内不同传输方向的信号进行比对，本研究还在多晶硅、氯化铊纳米晶体以及单晶硅样本中观测到与沟道效应相关的衬度信号。