Low Energy Positron Diffraction and Positron Re-emission Microscopy Experiments

布兰迪斯大学的高亮度正电子束 用于执行低能量正电子衍射（LEPD）和正电子 再发射显微镜（PRM）实验。 LEPD技术可以 提供化合物更精确结构测定 半导体表面比其电子对应物，低能量 电子衍射（LEED）。 所提出的实验设计 将目前80 nm的空间分辨率扩展到1 nm。 化合物 将研究半导体和金属表面。 的PRM 将产生50，000倍放大的正电子再发射图像 在低能量下从薄Ni（100）膜。 极度敏感 以及低能正电子对地下的非破坏性 缺陷和覆盖的原子将用于成像特征， 亚单层金属膜中的单空位和界面缺陷 生长，这是用传统的电子显微镜看不到的。

The high brightness positron beam at Brandeis University is being used to perform low energy positron diffraction (LEPD) and positron reemission microscope (PRM) experiments. The LEPD technique can provide a more precise structural determination of compound semiconductor surfaces than its electron counterpart, low energy electron diffraction (LEED). The proposed experiments are designed to extend the present 80 nm spatial resolution to 1nm. Compound semiconductors and metal surfaces will be investigated. The PRM will produce up to 50,000x magnified image of positrons reemitted at low energies from a thin Ni(100) film. The extreme sensitivity and nondestructiveness of low energy positrons to subsurface defects and overlying atoms will be used for imaging features, such as monovacancies an interfacial defects in submonolayer metal film growth, that can not be seen with conventional electron microscopy.