Study on the electronic states of the outermost surface layers by Metastable deexcitation spectroscopy.

本课题的目的是建立一台亚稳去激发光谱仪，并利用MDS测量最外层表面的电子结构。我们为MDS建造了一个波束源，它与一个已经在工作的特高压室结合在一起。我们采用氦的超音速喷嘴束作为亚稳态原子源。高压气体通过喷嘴膨胀进入真空。扩展后的流被位于下游10mm处的撇油器撇油，形成原子束。因此，我们需要两个平行的抽气阶段来抽走引入的气体。两个大的油扩散泵与一个铝合金箱式真空室相结合。我们发现需要另一个特高压室来减少特高压主室中样品的污染。结合用涡轮分子泵泵送的特高压小室，解决了这一问题。由于已设置在主室的能量分析仪的黑暗，未能获得MDS频谱。我们正在研制一种新型的高亮度分析仪。

The purpose of this project is to construct a machine for metastdble deexcitation spectroscopy and to measure the outermost surface electronic structures using MDS. We constructed a beam source for MDS and it combined with a UHV chamber which was already working. We adopted a supersonic nozzle beam of He as the metastable atom source. The high-pressure gases are expanded through a nozzle into vacuum. The expanded stream is skimmed by a skimmer located at 10mm downstream to form an atomic beam. Therefore, we need two pumping stages in parallel for evacuation of introduced gases. Two big oil diffusion pumps combined with a box type vacuum chamber which is made of aliminium alloy. We found that an another UHV chamber was required for reducing the contamination of the sample held in the UHV main chamber. Combining the small UHV chamber which is pumped by a turbomolecular pump, we settled the problem. Owing to darkness of an energy analzyer which was already set in the main chamber, it was unsuccessful to get a MDS spectrum. We are now preparing a new type of analyzer with high-brightness.