Positron Annihilation Induced Auger Electron Spectroscopy

这个实验计划将使用正电子湮灭诱导俄歇电子能谱（PAES）来研究表面和俄歇过程本身。现有的UTA磁导PAES系统将用于直接识别最顶层原子层的元素含量，并以极低的能量剂量率获得俄热光谱。要研究的系统包括(1)由铁、钕和钯组成的超薄金属薄膜在铜上的生长和相互扩散，(2)金属表面的吸附，(3)合金的表面偏析，(4)脆弱的吸附层和化学不稳定的系统，包括催化表面和导电聚合物上的有机分子。未来对正电子束的修正将使极化俄歇光谱的新形式成为可能，用于磁系统的研究，其中选择初始空穴的极化而不是出射电子的极化。

This experimental program will employ Positron annihilation induced Auger Electron Spectroscopy (PAES) for the study of surfaces and the Auger process itself. The exising UTA magnetically guided PAES system will be used to identify directly the elemental content of the top-most atomic layer and to obtain Auger spectra with extremely low energy dose rates. Systems to be studied include (1) the growth and interdiffusion of ultrathin metal films composed of iron, neodymium and palladium on copper, (2) adsorbates on metal surfaces, (3) suface segregation in alloys, and (4) fragile adsorbed layers and chemically unstable systems including organic molecules on catalytic surfaces and conducting polymers. Future modifications of the positron beam will make possible a new form of polarized Auger spectroscopy for use in the study of magnetic systems in which the polarization of the initial hole rather than the outgoing electron is selected.