Auger-photoelectron coincidence spectroscopy

光电子能谱和俄歇电子能谱被广泛用于表面的研究。然而，俄歇过程的基础研究仍在发展中。有趣的现象，如特定的网站俄歇，俄歇后的震荡光电发射和级联俄歇尚未完全阐明。将直径为26 mm的微型柱面镜电子能量分析器（CMA）同轴共焦地组装在同轴对称的镜分析器中，研制了一台俄歇-光电子符合谱（APECS）装置。CMA由电场屏蔽层、内外圆柱、针孔和电子倍增器组成。通过测量Si（111）表面的Si LVV俄歇- Si 2 p光电子符合谱测试了其性能. APECS装置的特征如下。1)由于同轴对称镜检偏器和恒模放大器的大立体角，使得符合信号的检测效率比以前提高了一个数量级。2)定位非常容易，因为同轴对称镜分析器和CMA共焦地组装在一个带有xyz定位和倾斜调节机构的杆上。3)它可以安装到一个多用途的真空室，因为它是在一个203毫米的外径conflat法兰与50毫米的伸缩机制。4)由于结构简单，零件数量相对较少，所以生产成本低。

Photoelectron spectroscopy and Auger electron spectroscopy are widely used for investigations of surfaces. Fundamental studies of Auger processes, however, are still developing. Interesting phenomena such as site-specific Auger, Auger subsequent to a shake-up photoemission and cascade Auger are not fully elucidated yet. By assembling a miniature cylindrical mirror electron energy analyzer (CMA) with a diameter of 26 mm in a coaxially symmetric mirror analyzer coaxially and confocally we have developed an apparatus for Auger-photoelectron coincidence spectroscopy (APECS). The CMA consists of a shield for electric field, inner and outer cylinders, a pinhole, and an electron multiplier. The performance was tested by measuring Si LVV Auger - Si 2p photoelectron coincidence spectra of a Si(111) surface. Features of the APECS apparatus are as follow. 1) Coincidence signal detection efficiency is improved by one order of magnitude from previous ones because of the large solid angle of the coaxially symmetric mirror analyzer and the CMA. 2) Positioning is quite easy, because the coaxially symmetric mirror analyzer and the CMA are assembled confocally on a rod with a mechanism for xyz positioning and tilt adjustment. 3) It can be installed to a multi-purpose ultrahigh vacuum chamber because it is constructed on a 203-mm-outer-diameter conflat flange with a 50-mm-retractable mechanism. 4) The production cost is low because the structure is simple and the number of the parts is relatively few.